Search results for: human pathogenic bacteria

Authors: Michael Augustus Akagbor

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When discussing human rights, the philosophical underpinnings of discussions about African realities are controversial, often hinging on whether human rights existed in pre-colonial Africa as not just a philosophy of thought but also a way of imagining the individual's place in society. Critics have often fixated on what many argue is the lack of socio-political structures that could have fostered the emergence and development of human rights contraptions in “mechanical” solidarities such as pre-colonial agrarian African societies. This paper debunks the notion that the perceived ‘absence’ of an ‘advanced’ and differentiated social system where the philosophical imaginaries of Hobbes and Locke could have emerged is not grounds to deny the imagined place of the human rights of the ‘individual’ in pre-colonial Africa. The paper adopts the qualitative methodology by reviewing and analyzing secondary data from various sources to advance the view that the concepts of human rights are not alien to indigenous Africa’s legal and political processes.

Keywords: human rights, reality, philosophical, Africa, individual

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Authors: Lina Wu

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The excessive discharge of nitrogen in sewage greatly intensifies the eutrophication of water bodies and threatens water quality. Nitrogen pollution control has become a global concern. The concentration of nitrogen in water is reduced by converting ammonia nitrogen, nitrate nitrogen and nitrite nitrogen into nitrogen-containing gas through biological treatment, physicochemical treatment and oxidation technology. However, some wastewater containing high ammonia nitrogen including landfill leachate, is difficult to be treated by traditional nitrification and denitrification because of its high COD content. The core process of denitrification is that denitrifying bacteria convert nitrous acid produced by nitrification into nitrite under anaerobic conditions. Still, its low-carbon nitrogen does not meet the conditions for denitrification. Many studies have shown that the natural autotrophic anammox bacteria can combine nitrous and ammonia nitrogen without a carbon source through functional genes to achieve total nitrogen removal, which is very suitable for removing nitrogen from leachate. In addition, the process also saves a lot of aeration energy consumption than the traditional nitrogen removal process. Therefore, anammox plays an important role in nitrogen conversion and energy saving. The short-range nitrification and denitrification coupled with anaerobic ammoX ensures total nitrogen removal. It improves the removal efficiency, meeting the needs of society for an ecologically friendly and cost-effective nutrient removal treatment technology. In recent years, research has found that the symbiotic system has more water treatment advantages because this process not only helps to improve the efficiency of wastewater treatment but also allows carbon dioxide reduction and resource recovery. Microalgae use carbon dioxide dissolved in water or released through bacterial respiration to produce oxygen for bacteria through photosynthesis under light, and bacteria, in turn, provide metabolites and inorganic carbon sources for the growth of microalgae, which may lead the algal bacteria symbiotic system save most or all of the aeration energy consumption. It has become a trend to make microalgae and light-avoiding anammox bacteria play synergistic roles by adjusting the light-to-dark ratio. Microalgae in the outer layer of light particles block most of the light and provide cofactors and amino acids to promote nitrogen removal. In particular, myxoccota MYX1 can degrade extracellular proteins produced by microalgae, providing amino acids for the entire bacterial community, which helps anammox bacteria save metabolic energy and adapt to light. As a result, initiating and maintaining the process of combining dominant algae and anaerobic denitrifying bacterial communities has great potential in treating landfill leachate. Chlorella has a brilliant removal effect and can withstand extreme environments in terms of high ammonia nitrogen, high salt and low temperature. It is urgent to study whether the algal mud mixture rich in denitrifying bacteria and chlorella can greatly improve the efficiency of landfill leachate treatment under an anaerobic environment where photosynthesis is stopped. The optimal dilution concentration of simulated landfill leachate can be found by determining the treatment effect of the same batch of bacteria and algae mixtures under different initial ammonia nitrogen concentrations and making a comparison. High-throughput sequencing technology was used to analyze the changes in microbial diversity, related functional genera and functional genes under optimal conditions, providing a theoretical and practical basis for the engineering application of novel bacteria-algae symbiosis system in biogas slurry treatment and resource utilization.

Keywords: nutrient removal and recovery, leachate, anammox, Partial nitrification, Algae-bacteria interaction

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Authors: Alec Chabwinja, Cannan Tawonezvi, Jerneja Vidmar, Constance Chingwaru, Walter Chingwaru

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Objective: To evaluate the potential of commercial fermented / probiotic products available in Zimbabwe or internationally, and strains of Lactobacillus plantarum (L. plantarum) as prophylaxis and therapy against diarrhoeal and sexually transmitted infections. Methods: The antimicrobial potential of cultures of lactobacilli enriched from 4 Zimbabwean commercial food/beverage products, namely Dairibord Lacto sour milk (DLSM), Probrand sour milk (PSM), Kefalos Vuka cheese (KVC) and Chibuku opaque beer (COB); three probiotic products obtainable in Europe and internationally; and four strains of L. plantarum obtained from Balkan traditional cheeses and Zimbabwean foods against clinical strains of Escherichia coli (E. coli) and non-clinical strains of Candida albicans and Rhodotorula spp. was assayed using the well diffusion method. Three commercial Agar diffusion assay and a competitive exclusion assay were carried out on Mueller-Hinton agar. Results: Crude cultures of putative lactobacillus strains obtained from Zimbabwean dairy products (Probrand sour milk, Kefalos Vuka vuka cheese and Chibuku opaque beer) exhibited significantly greater antimicrobial activities against clinical strains of E. coli than strains of L. plantarum isolated from Balkan cheeses (CLP1, CLP2 or CLP3) or crude microbial cultures from commercial paediatric probiotic products (BG, PJ and PL) of a culture of Lactobacillus rhamnosus LGG (p < 0.05). Furthermore, the following has high antifungal activities against the two yeasts: supernatant-free microbial pellet (SFMP) from an extract of M. azedarach leaves (27mm ± 2.5) > cell-free culture supernatants (CFCS) from Maaz Dairy sour milk and Mnandi sour milk (approximately 26mm ± 1.8) > CFCS and SFMP from Amansi hodzeko (25mm ± 1.5) > CFCS from Parinari curatellifolia fruit (24mm ± 1.5), SFMP from P. curatellifolia fruit (24mm ± 1.4) and SFMP from mahewu (20mm ± 1.5). These cultures also showed high tolerance to acidic conditions (~pH4). Conclusions: The putative lactobacilli from four commercial Zimbabwean dairy products (Probrand sour milk, Kefalos Vuka vuka cheese and Chibuku opaque beer), and three strains of L. plantarum from Balkan cheeses (CLP1, CLP2 or CLP3) exhibited high antibacterial activities, while Maaz Dairy sour-, Mnandi sour- and Amansi hodzeko milk products had high antifungal activities. Our selection of Zimbabwean probiotic products has potential for further development into probiotic products for use in the control diarrhea caused by pathogenic strains of E. coli or yeast infections. Studies to characterise the probiotic potential of the live cultures in the products are underway.

Keywords: lactic acid bacteria, Staphylococcus aureus, Streptococcus spp, yeast, inhibition, acid tolerance

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Authors: Febi Eka Putri, Prabowo Anggorono

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Human Trafficking has become a threat in the global phenomenon, including Indonesia as a country adopting democracy to uphold the human rights value. Indonesia is classified as a source of trafficking in persons which dominate by women and children for sexual exploitation and forced labor purposes. In this case, Indonesia has committed to combat trafficking in persons by enacted domestic law to criminalize all types of human trafficking in domestic and international level. Tracing to the efforts, we cannot just simplify it, however, in 2016 Indonesia has placed as a tier 2 country because the government does not fully achieve the minimum standard by U. S. Trafficking Victims Protection Act due to only making efforts as progress. While as a part of ASEAN member, Indonesia has signed ASEAN Human Rights Declaration but when it comes to Human Trafficking issue, there is only few ASEAN member who has ratified ASEAN Convention on Trafficking in Persons, in particular Women and Children such as Singapore, Cambodia, and Thailand. This brings the evidence to structuring the role of Indonesia to combat human trafficking.

Keywords: Indonesia, Association of Southeast Asian Nations (ASEAN), human trafficking, Tier 2 country

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Authors: Kawinphat Lertpongmanee

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The problems of trafficking human beings were continuously violent in Thailand. The problems occurred from a variety of factors such as unemployment, agricultural workers’ urban immigration, sex tour, attitude of materialism society, divorced family, unsavourily effected law, and officers’ ignorance. The purposes of this study were to study the structure, connection, a number of trafficking human beings in Thailand. Qualitative and quantitative and results of previous research were used in this research. The previous procurers, interested persons, experienced people, human beings-aiding organization, and women-children rights organization were interviewed in depth. The field was used in a variety of regions. The findings showed that the structure and connection of trafficking human beings and their values are $8,750 million. There are 240,000 people in trafficked human beings. The trend of trafficking human beings grows continuously. It is changed according to economic circumstance, society and culture, and law. The state must be aware of its problem. The law is enacted by adding high penalty for serious fear.

Keywords: human trade, prostitution trafficking, trafficking in women and children, Thailand

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Authors: Claudio Lamilla, Misael Riquelme, Victoria Saez, Fernanda Sepulveda, Monica Pavez, Leticia Barrientos

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Biosurfactants are compounds synthesized by microorganisms that show various chemical structures, including glycolipids, lipopeptides, polysaccharide-protein complex, phospholipids, and fatty acids. These molecules have attracted attention in recent years due to the amphipathic nature of these compounds, which allows their application in various activities related to emulsification, foaming, detergency, wetting, dispersion and solubilization of hydrophobic compounds. Microorganisms that produce biosurfactants are ubiquitous, not only present in water, soil, and sediments but in extreme conditions of pH, salinity or temperature such as those present in Antarctic ecosystems. Due to this, it is of interest to study biosurfactants producing bacterial strains isolated from Antarctic environments, with the potential to be used in various biotechnological processes. The objective of this research was to characterize biosurfactants produced by bacterial strains isolated from Antarctic environments, with potential use in biotechnological processes for the cleaning of sites contaminated with hydrocarbons. The samples were collected from soils and sediments in the South Shetland Islands and the Antarctic Peninsula, during the Antarctic Research Expedition INACH 2016, from both pristine and human occupied areas (influenced). The bacteria isolation was performed from solid R2A, M1 and LB media. The selection of strains producing biosurfactants was done by hemolysis test on blood agar plates (5%) and blue agar (CTAB). From 280 isolates, it was determined that 10 bacterial strains produced biosurfactants after stimulation with different carbon sources. 16S rDNA taxonomic markers, using the universal primers 27F-1492R, were used to identify these bacterias. Biosurfactants production was carried out in 250 ml flasks using Bushnell Hass liquid culture medium enriched with different carbon sources (olive oil, glucose, glycerol, and hexadecane) during seven days under constant stirring at 20°C. Each cell-free supernatant was characterized by physicochemical parameters including drop collapse, emulsification and oil displacement, as well as stability at different temperatures, salinity, and pH. In addition, the surface tension of each supernatant was quantified using a tensiometer. The strains with the highest activity were selected, and the production of biosurfactants was stimulated in six liters of culture medium. Biosurfactants were extracted from the supernatants with chloroform methanol (2:1). These biosurfactants were tested against crude oil and motor oil, to evaluate their displacement activity (detergency). The characterization by physicochemical properties of 10 supernatants showed that 80% of them produced the drop collapse, 60% had stability at different temperatures, and 90% had detergency activity in motor and olive oil. The biosurfactants obtained from two bacterial strains showed a high activity of dispersion of crude oil and motor oil with halos superior to 10 cm. We can conclude that bacteria isolated from Antarctic soils and sediments provide biological material of high quality for the production of biosurfactants, with potential applications in the biotechnological industry, especially in hydrocarbons -contaminated areas such as petroleum.

Keywords: antarctic, bacteria, biosurfactants, hydrocarbons

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Authors: C. Miranda, R. Soares, S. Cunha, L. Ferreira, G. Igrejas, P. Poeta

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Different animal species, including ornamental animals, are reported as potential reservoirs of antibiotic resistance genes. Consequently, these resistances can be disseminated in the environment and transferred to humans. Moreover, multidrug-resistant bacteria reduce the efficacy of antibiotics, as the case of vancomycin-resistant enterococci. Enterococcus faecalis and E. faecium are described as the main nosocomial pathogens. In this line, the aim of this study was to characterize resistance and virulence genes of enterococci species isolated from samples of food supplied to ornamental animals during 2020. The 29 enterococci isolates (10 E. faecalis and 19 E. faecium) were tested for the presence of the resistance genes for the following antibiotics: erythromicyn (ermA, ermB and ermC), tetracycline (tetL, tetM, tetK and tetO), quinupristin/dalfopristin (vatD and vatE), gentamicin (aac(6’)-aph(2’’)-Ia), chloramphenicol (catA), streptomycin (ant(6)-Ia) and vancomycin (vanA and vanB). The same isolates were also tested for 10 virulence factors genes (esp, ace, gelE, agg, fsr, cpd, cylA, cylB, cylM and cylLL). The resistance and virulence genes were performed by PCR, using specific primers and conditions. Negative and positive controls were used in all PCR assays. The most prevalent resistance genes detected in both enterococci species were ermB (n=15, 52%), ermC (n=7, 24%), tetK (n=8, 28%) and vatE (n=4, 14%). Resistance genes for vancomycin were found in ten (34%) E. faecalis and ten (34%) E. faecium isolates. Only E. faecium isolates showed the presence of ermA (n=2, 7%), tetL (n=13, 45%) and ant(6)-Ia gene (n=4, 14%). A total of nine (31%) enterococci isolates were classified as multidrug-resistant bacteria (3 E. faecalis and 6 E. faecium). In three E. faecalis and one E. faecium were not detected resistance genes. The virulence genes detected in both species were agg (n=6, 21%) and cylLL (n=11, 38%). In general, each isolate showed only one of these virulence genes. Five E. faecalis and eleven E. faecium isolates were negative for all analyzed virulence genes. These preliminary results showed the presence of multidrug-resistant enterococci in food supplied to ornamental animals, in particular vancomycin-resistant enterococci. This genotypic characterization reinforces the relevance to public health in the control of antibiotic-resistant bacteria.

Keywords: antibiotic resistance, enterococci, feed, ornamental animals

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Authors: Kanika Chowdhary, Satyawati Sharma

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Endophytic microbes are hosted inside plants in a symbiotic and hugely benefitting relationship. Exploring agriculturally beneficial endophytes is quite a prospective field of research. In the present work fungal endophytes associated with aromatic plant Ocimum basicilium L. were investigated for biocontrol potential. The anti-plant pathogenic activity of fungal endophytes was tested against causal agent of stem rot Sclerotinia sclerotiorum. 75 endophytic fungi were recovered through culture-dependent approach. Fungal identification was performed both microscopically and by rDNA ITS sequencing. Curvuaria lunata (Sb-6) and Colletotrichum lindemuthianum (Sb-8) inhibited 86% and 72% mycelia growth of S. sclerotinia on Sabouraud dextrose agar medium at 7.4 pH. Small-scale fermentation was carried out on sterilised oatmeal grain medium. In another set of experiment, fungi were grown in oatmeal grain medium amended with certain biostimulants such as aqueous seaweed extract (10% v/w); methanolic seaweed extract (5% v/w); cow urine (20% v/w); biochar (10% w/w) in triplicate along with control of each to ascertain the degree of metabolic difference and anti-plant pathogenic activity induced. Phytochemically extracts of both the fungal isolates showed the presence of flavanoids, phenols, tannins, alkaloids and terpenoids. Ethylacetate extract of C. lunata and C. lindemuthianum suppressed S. sclerotinia conidial germination at IC50 values of 0.514± 0.02 and 0.913± 0.04 mg/ml. Therefore, fungal endophytes of O. basicilium are highly promising bio-resource agent, which can be developed further for sustainable agriculture.

Keywords: endophytic fungi, ocimum basicilium, sclerotinia sclerotiorum, biostimulants

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Authors: Mara Varelaki

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In response to the challenge of the environmental crisis the discipline of environmental ethics examines the relation of human beings towards the environment and the value of the non-human constituents of the surrounding world. In the face of this crisis, assumptions regarding human and nature relations ought to be traced and reexamined because they can cause difficulties in diagnosing problematic attitudes towards the environment and non-human animals. This paper presents the claims that European and the Judea-Christian cosmogonic myths place the human figure in the core of the creation of the cosmos, thus verifying a hierarchical structure where humans occupy the top, and they establish a perception of nature as a non-human other. By doing so, these narratives provide some justification to the notion of the human-nature dichotomy and the human domination over other life forms and ecosystems. These anthropocentric assumptions evolved into what Hilde Lindemann terms master narratives and their influence extents to ecocentric ethical theories which attempt, and often fail, to shed the anthropocentrism of the western ethical tradition. The goal of this paper is (1) to trace the anthropocentric assumptions embedded in western thought and (2) articulate how they maintain their grip on our contemporary understanding of the human relation to and position within the environment, thus showing the need for a method of detecting and bracketing anthropocentric assumptions in social narratives and ethical frameworks.

Keywords: cosmogonies, anthropocentrism, human/nature dichotomy, master narratives, ecocentrism

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Authors: Meenakshi Srivastava, A. K. Mishra

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This study characterizes the metabolic versatility of denitrifying bacterial communities residing in the paddy soil using the GC-MS based Phospholipid Fatty Acid (PLFA) analyses simultaneously with nosZ gene based PCR-DGGE (Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis) and real time Q-PCR analysis. We have analyzed the abundance of nitrous oxide reductase (nosZ) genes, which was subsequently related to soil PLFA profile and DGGE based denitrifier community structure. Soil denitrifying bacterial community comprised majority or dominance of Ochrobactrum sp. following Cupriavidus and uncultured bacteria strains in paddy soil of selected sites. Initially, we have analyzed the abundance of the nitrous oxide reductase gene (nosZ), which was found to be related with PLFA based lipid profile. Chandauli of Eastern UP, India represented greater amount of lipid content (C18-C20) and denitrifier’s diversity. This study suggests the positive co-relation between soil PLFA profiles, DGGE, and Q-PCR data. Thus, a close networking among metabolic abilities and taxonomic composition of soil microbial communities existed, and subsequently, such work at greater extent could be helpful in managing nutrient dynamics as well as microbial dynamics of paddy soil ecosystem.

Keywords: denaturing gradient gel electrophoresis, DGGE, nitrifying and denitrifying bacteria, PLFA, Q-PCR

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Authors: Reham K. Sebaih, Afaf I. Shehata , Awatif A. Hindi, Tarek Gheith, Amal A. Hazzani Anas Al-Orjan

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Staphylococci spp are ubiquitous gram-positive bacteria is often associated with infections, especially nosocomial infections, and antibiotic resistanceStudy pathogenic bacteria and its use as a tool in the technology of Nano biology and molecular genetics research of the latest research trends of modern characterization and definition of different multiresistant of bacteria including Staphylococci. The Staphylococci are widespread all over the world and particularly in Saudi Arabia The present work study was conducted to evaluate the effect of five different types of nanoparticles (biosynthesized zinc oxide, Spherical and rod of each silver and gold nanoparticles) and their antibacterial impact on the Staphylococcus species. Ninety-six isolates of Staphylococcus species. Staphylococcus aureus, Staphylococcus epidermidis, MRSA were collected from different sources during the period between March 2011G to June 2011G. All isolates were isolated from inpatients and outpatients departments at Royal Commission Hospital in Yanbu Industrial, Saudi Arabia. High percentage isolation from males(55%) than females (45%). Staphylococcus epidermidis from males was (47%), (28%), and(25%). For Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA. Isolates from females were Staphylococcus aureus with higher percent of (47%), (30%), and (23%) for MRSA, Staphylococcus epidermidis. Staphylococcus aureus from wound swab were the highest percent (51.42%) followed by vaginal swab (25.71%). Staphylococcus epidermidis were founded with higher percentage in blood (37.14%) and wound swab (34.21%) respectively related to other. The highest percentage of methicillin-resistant Staphylococcus aureus (MRSA)(80.77%) were isolated from wound swab, while those from nostrils were (19.23%). Staphylococcus species were isolates in highest percentage from hospital Emergency department with Staphylococcus aureus (59.37%), Methicillin-resistant Staphylococcus aureus (MRSA) (28.13%)and Staphylococcus epidermidis (12.5%) respectively. Evaluate the antibacterial property of Zinc oxide, Silver, and Gold nanoparticles as an alternative to conventional antibacterial agents Staphylococci isolates from hospital sources we screened them. Gold and Silver rods Nanoparticles to be sensitive to all isolates of Staphylococcus species. Zinc oxide Nanoparticles gave sensitivity impact range(52%) and (48%). The Gold and Silver spherical nanoparticles did not showed any effect on Staphylococci species. Zinc Oxide Nanoparticles gave bactericidal impact (25%) and bacteriostatic impact (75%) for of Staphylococci species. Detecting the association of nanoparticles with Staphylococci isolates imaging by scanning electron microscope (SEM) of some bacteriostatic isolates for Zinc Oxide nanoparticles on Staphylococcus aureus, Staphylococcus epidermidis and Methicillin resistant Staphylococcus aureus(MRSA), showed some Overlapping Bacterial cells with lower their number and appearing some appendages with deformities in external shape. Molecular analysis was applied by Multiplex polymerase chain reaction (PCR) used for the identification of genes within Staphylococcal pathogens. A multiplex polymerase chain reaction (PCR) method has been developed using six primer pairs to detect different genes using 50bp and 100bp DNA ladder marker. The range of Molecular gene typing ranging between 93 bp to 326 bp for Staphylococcus aureus and Methicillin resistant Staphylococcus aureus by TSST-1,mecA,femA and eta, while the bands border were from 546 bp to 682 bp for Staphylococcus epidermidis using icaAB and atlE. Sixteen isolation of Staphylococcus aureus and Methicillin resistant Staphylococcus aureus were positive for the femA gene at 132bp,this allowed the using of this gene as an internal positive control, fifteen isolates of Staphylococcus aureus and Methicillin resistant Staphylococcus aureus were positive for mecA gene at163bp.This gene was responsible for antibiotic resistant Methicillin, Two isolates of Staphylococcus aureus and Methicillin resistant Staphylococcus aureus were positive for the TSST-1 gene at326bp which is responsible for toxic shock syndrome in some Staphylococcus species, None were positive for eta gene at 102bpto that was responsible for Exfoliative toxins. Six isolates of Staphylococcus epidermidis were positive for atlE gene at 682 bp which is responsible for the initial adherence, three isolates of Staphylococcus epidermidis were positive for icaAB gene at 546bp that are responsible for mediates the formation of the biofilm. In conclusion, this study demonstrates the ability of the detection of the genes to discriminate between infecting Staphylococcus strains and considered biological tests, they may potentiate the clinical criteria used for the diagnosis of septicemia or catheter-related infections.

Keywords: multiplex polymerase chain reaction, toxic shock syndrome, Staphylococcus aureus, nosocomial infections

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Authors: Lynamata Chhun

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Human Rights enforcement in the newly independent countries like Asian and African has always been penetrating issues. In spite, the existing of the Universal Declaration of Human Rights (UDHR), regions like Africa and Asia where values and cultural norms far differ from the concept had formed their own Human Rights instruments to tackle Human Rights issues in their regions instead of embracing the concept of UDHR completely. ASEAN Human Rights Declaration is one of the examples. This paper aims to examine the enforcement of Human Rights in South East Asia in the context of ASEAN regional integration. Precisely, the author attempts to analyse the effectiveness in undertaking Human Rights issues in the region by applying both the existing international and regional frameworks using the Myanmar Rohingya Crisis as the case study. The methodology of the paper is qualitative analysis where cross-impact analysis is employed to examine the case study. It is anticipated that the main findings of this paper will illuminate how applicable the international instruments are in comparison to the regional instruments in apprehending the human rights issues and will shed light on how ASEAN and dialogue partners should cooperate in the future regarding with the challenging issues of Human Rights in the region.

Keywords: ASEAN Human Rights Declaration, ASEAN integration, ASEAN way, international and regional instruments, Universal Declaration of Human Rights

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Authors: Raana Babadi Fathipour

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Biofilms, those intricate structures of microbial aggregation that emerge as microorganisms adhere to animate or inanimate surfaces, possess an innate capacity to shield their inhabitants from adversities within the environment whilst fortifying their endurance against antimicrobial agents. This remarkable aspect facilitates the persistence and virulence of said microorganisms, establishing biofilm formation as an integral component of bacterial survival mechanisms. However, should foodborne pathogens adopt this mode of existence, the potentiality for foodborne disease infections becomes alarmingly intensified—an alarming prospect that harbors significant public health hazards and engenders deleterious economic ramifications. Thus, due to these consequences lurking on the horizon, extensive research concentrating upon comprehending biofilms and devising efficacious removal strategies assumes a position imbued with paramount importance within the realm of the food industry. The problem of food waste resulting from spoilage in the food industry continues to present a widespread challenge to both environmental sustainability and the security of our food supplies. In this comprehensive analysis, we delve into the formation of bacterial biofilms, highlighting the specific issues they pose within the realm of food production. Additionally, we provide an overview of various types of common foodborne pathogens that tend to thrive in these biofilms. Furthermore, we summarize existing strategies aimed at tackling or managing detrimental bacterial biofilm growth. We also introduce contemporary approaches that show promise in terms of controlling this issue and highlight their potential for further advancement. Ultimately, our focus lies on outlining prospects for future development as they pertain specifically to combatting bacterial biofilms within the field.

Keywords: foodborne pathogens, food safety, biofilm, resistance, quorum-sensing

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Authors: Yinan Zhou

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One in four people in the world still lack access to clean drinking water, and there is a current lack of cost-effective ways for water-scarce regions to access it. This study seeks to investigate the solutions to water filtration in rural China as well as test the feasibility of using angiosperms as xylem candidates. Four angiosperms that are found in China and around Asia were subject to three tests to test their filtration capacity: ink water filtration, creek water filtration, and microparticle filtration. Analysis of the experiments demonstrated that Celtis Sinensis was able to produce one of the clearest solutions, filter out large debris and bacteria, and reject microparticles almost completely. Celtis Sinensis proves that angiosperm xylem filters are also competent filter candidates and, due to their availability in China, can be used as a nearby source of water filtration. Further research should be done on scaling production to a larger scale and also on the filtration of viruses.

Keywords: xylem filter, water quality, China, angiosperms, bacteria

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Authors: Slimane Mokrani, Nabti El hafid

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Description of the subject: Currently, several efforts focus on the study of biodiversity, microbial biotechnology, and the use of ecological strategies. Objectives: The aim of this present work is to determine the functional diversity of bacteria in rhizospheric and non-rhizospheric soils of different plants. Methods: Bacteria were isolated from soil and identified based on physiological and biochemical characters and genotypic taxonomy performed by 16S rDNA and BOX-PCR. As well as the characterization of various PGPR traits. Then, they are tested for their effects on the stimulation of seed germination and the growth of Phaseolus vulgaris L. As well as their biological control activities with regard to the phytopathogenic bacterial isolate Xapf. Results and Discussion: The biochemical and physiological identification of 75 bacterial isolates made it possible to associate them with the two groups of fluorescent Pseudomonas (74.67%) and non-fluorescent Pseudomonas (25.33%). The identification by 16S rDNA of 27 strains made it possible to attribute the majority of the strains to the genus Pseudomonas (81.48%), Serratia (7.41%) and Bacillus (11.11%). The bacterial strains showed a high capacity to produce IAA, siderophores, HCN and to solubilize phosphate. A significant stimulation of germination and growth was observed by applying the Pseudomonas strains. Furthermore, significant reductions in the severity and intensity of the disease caused caused by Xapf were observed. Conclusion: The bacteria described in this present study endowed with different PGPR activities seem to be very promising for their uses as biological control agents and bio-fertilization.

Keywords: biofertilization, biological control, phaseolus vulgaris L, pseudomonas, Xanthomonas axonopodis pv. phaseoli var. fuscans and common blight

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Authors: Shubhashree Mahalik, Dhanesh Kumar, Jatin Kumar Pradhan

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Odisha is one of the coastal states situated on the eastern part of India with 480 km long coastline. The coastal Odisha is referred to as "Gift of Six Rivers". Balasore, a major coastal district of Odisha is bounded by Bay of Bengal in the East having 26 km long seashore. It is lined with several estuaries rich in biodiversity.Several studies have been carried out on the macro flora and fauna of this area but very few documented information are available regarding microbial biodiversity. In the present study, an attempt has been made to isolate and identify bacteria found along the estuaries of Balasore.Many marine microorganisms are sources of natural products which makes them potential industrial organisms. So the ability of the isolated bacteria to secrete one such industrially significant product, PHB (Polyhydroxybutyrate) has been elucidated. Several rounds of sampling, pure culture, morphological, biochemical and phylogenetic screening led to the identification of two PHB producing strains. Isolate 5 was identified to be Brevibacillus sp. and has maximum similarity to Brevibacillus parabrevis (KX83268). The isolate was named as Brevibacillus sp.KEI-5. Isolate 8 was identified asLysinibacillus sp. having closest similarity withLysinibacillus boroni-tolerance (KP314269) and named as Lysinibacillus sp. KEI-8.Media, temperature, carbon, nitrogen and salinity requirement were optimized for both isolates. Submerged fermentation of both isolates in Terrific Broth media supplemented with optimized carbon and nitrogen source at 37°C led to significant accumulation of PHB as detected by colorimetric method.

Keywords: Bacillus, estuary, marine, Odisha, polyhydroxy butyrate

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Authors: Agostinho Antunes

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The completion of the human genome sequencing in 2003 opened a new perspective into the importance of whole genome sequencing projects, and currently multiple species are having their genomes completed sequenced, from simple organisms, such as bacteria, to more complex taxa, such as mammals. This voluminous sequencing data generated across multiple organisms provides also the framework to better understand the genetic makeup of such species and related ones, allowing to explore the genetic changes underlining the evolution of diverse phenotypic traits. Here, recent results from our group retrieved from comparative evolutionary genomic analyses of selected marine animal species will be considered to exemplify how gene novelty and gene enhancement by positive selection might have been determinant in the success of adaptive radiations into diverse habitats and lifestyles.

Keywords: comparative genomics, adaptive evolution, bioinformatics, phylogenetics, genome mining

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Authors: Wendu Admasu, Assefa Sintayehu, Alemu Gezahgne, Zewdu Terefework

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Eucalyptus is the most widely planted forest tree species in the world. In Ethiopia, pathogenic fungi pose an increasing threat to Eucalyptus species. Due to limited research, there is insufficient information on the associated diseases and pathogens. This study investigated Eucalyptus diseases, the extent of their damage, and the causal fungal pathogens. A Eucalyptus disease survey was conducted in the Eucalyptus forestry areas of Ethiopia during the growth years 2019/20 and 2020/21. Disease assessment and sampling were carried out in eighteen plantations at nine locations. E. camaldulensis was the most dominant species planted in the surveyed areas. The field study shows a high incidence and severity of canker diseases. Diseased stem and branch samples were collected, cultured on malt extract agar media and studied. The results of morphological and ITS sequence analysis confirmed that the fungal species Neofusicoccum parvum, Lasiodiplodia theobromae, and Aplosporella hesperidica caused the observed canker symptoms. This is the first report of Lasiodiplodia theobromae and Aplosporella hesperidica causing diseases in Eucalyptus plants in Ethiopia. Changes in global climate and environmental factors, such as altitude, are believed to have a strong impact on the susceptibility of Eucalyptus plants to diseases. Strict quarantine practices and continuous monitoring of pathogenic and endophytic fungal species associated with Eucalyptus trees are issued to be prioritized to effectively control and manage the disease.

Keywords: Neofusicoccum, Lasiodiplodia, Aplosporella, pathogenicity, phylogeny, severity

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Authors: M. Ottenbrite, G. Yilmaz, J. Devenish, M. Kang, H. Dan, M. Lin, C. Lau, C. Carrillo, K. Bessonov, J. Nash, E. Topp, J. Guan

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Consumption of food contaminated by antibiotic-resistant (AR) bacteria may lead to the transmission of AR genes in the gut microbiota and cause AR bacterial infection, a significant public health concern. However, information is limited on if and how background microbes from the food matrix (food microbes) may influence resistance transmission. Thus, we assessed the colonization of a β-lactam resistant Salmonella Heidelberg strain (donor) and a β-lactam susceptible S. Typhimurium strain (recipient) and the transfer of the resistance genes in the mouse gut in the presence or absence of food microbes that were derived from washing freshly-harvested carrots. Mice were pre-treated with streptomycin and then inoculated with both donor and recipient bacteria or recipient only. Fecal shedding of the donor, recipient, and transconjugant bacteria was enumerated using selective culture techniques. Transfer of AR genes was confirmed by whole genome sequencing. Gut microbial composition was determined by 16s rRNA amplicon sequencing. Significantly lower numbers of donors and recipients were shed from mice that were inoculated with food microbes compared to those without food microbe inoculation. S. Typhimurium transconjugants were only recovered from mice without inoculation of food microbes. A significantly higher survival rate was in mice with vs. without inoculation of food microbes. The results suggest that the food microbes may compete with both the donor and recipient Salmonella, limit their growth and reduce transmission of the β-lactam resistance gene in the mouse gut.

Keywords: antibiotic resistance, gene transfer, gut microbiota, Salmonella infection

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Authors: Amel Bouderhem, Aminata Ould El Hadj Khelil, Amina N. Djrarbaoui, Aroussi Aroussi

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The present work aims to find the influence of the nature of the soil on the effectiveness of the biodegradation of hydrocarbons by a mixture of bacterial strains hydrocarbonoclastes. Processes of bioaugmentation and biostimulation trial are applied to samples of soils polluted voluntarily by the crude oil. For the evaluation of the biodegradation of hydrocarbons, the bacterial load, the pH and organic carbon total are followed in the different experimental batches. He bacterial load of the sandy soil varies among the witnesses of 45,2 .108 CFU/ml at the beginning of the experimentation to 214,07.108 CFU/ml at the end of the experiment. Of the soil silty-clay varies between 103,31 .108 CFU/ml and 614,86.108 CFU/ml . It was found a strong increase in the bacterial biomass during the processing of all samples. This increase is more important in the samples of sand bioaugmente or biomass increased from 63.16 .108 CFU/ml to 309.68 .108 CFU/ml than in soil samples silty clay- bioaugmente whose content in bacteria evolved of 73,01 .108 CFU/ml to 631.80 . 108CFU/ml

Keywords: pollution, hydrocarbons, bioremediation, bacteria hydrocarbonoclastes, ground, texture

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Authors: P. S. BEDI* , Neavty Thakur, Balvınder Sıngh

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In the present study an attempt has been made to prepare the crude extracts of leaves and stem of ‘Girardinia heterophylla’ by using various solvents like petroleum ether, ethanol and double distilled water. The samples were given the code NGLS 1, NGLS 2, NGLS 3, NGSS 1, NGSS 2 and NGSS 3 respectively. All the extracts were used to study their antimicrobial activity against gram positive bacteria eg. Bacillus subtilis, Gram negative bacteria eg. E. coli, K. pneumonia and antifungal activity against Aspergillus niger. The results of the antimicrobial activity showed that all the crude extracts of the plant posseses antibacterial activity. Maximum antibacterial activity was shown by NGLS 2, NGLS 3 and NGSS 3 against K. pneumonia. The growth of fungus A. niger was also inhibited by all the crude extracts. Maximum inhibition was shown by NGSS 2 followed by NGSS 1.

Keywords: Girardinia heterophylla, leaves and stem extracts, Antibacterial activity, antifungal activity.

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Authors: Iddrisu Ibrahim, Joseph Atia Ayariga, Junhuan Xu, Daniel Abugri, Boakai Robertson, Olufemi S. Ajayi

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The emergence of multidrug resistance poses a huge risk to public health globally. Yet these recalcitrant pathogens continue to rise in incidence rate, with resistance rates significantly outpacing the speed of antibiotic development. This, therefore, presents an aura of related health issues such as untreatable nosocomial infections arising from organ transplants and surgeries, as well as community-acquired infections that are related to people with compromised immunity, e.g., diabetic and HIV patients, etc. There is a global effort to fight multidrug-resistant pathogens spearheaded by the World Health Organization, thus calling for research into novel antimicrobial agents to fight multiple drug resistance. Previously, our laboratory demonstrated that Cannabidiol (CBD) was an effective antimicrobial against Salmonella typhimurium (S. typhimurium). However, we observed resistance development over time. To understand the mechanisms S. typhimurium uses to develop resistance to Cannabidiol (CBD), we studied the abundance of bacteria lipopolysaccharide (LPS) and membrane sterols of both susceptible and resistant S. typhimurium. Using real-time quantitative polymerase chain reaction (RT-qPCR), we also analyzed the expression of selected genes known for aiding resistance development in S. typhimurium. We discovered that there was a significantly higher expression of blaTEM, fimA, fimZ, and integrons in the CBD-resistant bacteria, and these were also accompanied by a shift in abundance in cell surface molecules such as lipopolysaccharide (LPS) and sterols.

Keywords: antimicrobials, resistance, cannabidiol, gram-negative bacteria, integrons, blaTEM, Fim, LPS, ergosterols

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Authors: Abishek Poudel

Abstract:

Human-tiger conflicts are serious issues of conflicts between local people and park authority and the conflicting situation potentially play negative role in park management. The study aimed (1) To determine the trend and nature of human-tiger conflicts (2) To understand people's perception and mitigation measures towards tiger conservation. Both primary and secondary information were used to determine human- tiger conflicts in Chitwan National Park. Systematic random sampling with 5% intensity was done to collect the perception of the villagers regarding human-tiger conflicts. The study sites were selected based on frequencies of incidences of human attacks and livestock depredation viz. Rajahar and Ayodhyapuri VDCs respectively. The trend of human casualties by tiger has increased in last five year whereas the trend of livestock has decreased. Reportedly, between 2008 and 2012, tigers killed 22 people, injured 10 and killed at least 213 livestock. Conflict was less common in the park and more intense in the sub-optimal habitats of Buffer Zone. Goat was the most vulnerable livestock followed by cattle. The livestock grazing and human intrusion into tiger habitat were the causes of conflicts. Developing local stewardship and support for tiger conservation, livestock insurance, and compensation policy simplification may help reduce human-tiger conflicts.

Keywords: livestock depredation, sub optimal habitat, human-tiger, local stewardship

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Authors: Sarah Devi Silvian, Hanna Shobrina Iqomatul Haq, Fara Cholidatun Nabila, Agustin Krisna Wardani

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Bacteria ability to survive in antibiotic is controlled by the presence of gene that encodes the antibiotic resistance protein. The instability of the antibiotic resistance gene can be observed by exposing the bacteria under the lethal dose of antibiotic. Low concentration of antibiotic can induce mutation, which may take a role in bacterial adaptation through the antibiotic concentration. Lactobacillus casei FNCC 0090 is one of the probiotic bacteria that has an ability to survive in tetracycline by expressing the tetM gene. The aims of this study are to observe the possibilities of mutation happened in L.casei FNCC 0090 by exposing in sub-lethal dose of tetracycline and also observing the instability of the tetM gene by comparing the sequence between the wild type and mutant. L.casei FNCC 0090 has a lethal dose in 60 µg/ml, low concentration is applied to induce the mutation, the range from 10 µg/ml, 15 µg/ml, 30 µg/ml, 45 µg/ml, and 50 µg/ml. L.casei FNCC 0090 is exposed to the low concentration from lowest to the highest concentration to induce the adaptation. Plasmid is isolated from the highest concentration culture which is 50 µg/ml by using modified alkali lysis method with the addition of lysozyme. The tetM gene is isolated by using PCR (Polymerase Chain Reaction) method, then PCR amplicon is purified and sequenced. Sequencing is done on both samples, wild type and mutant. Both sequences are compared and the mutations can be traced in the presence of nucleotides changes. The changing of the nucleotides means that the tetM gene is instable.

Keywords: L. casei FNCC 0090, probiotic, tetM, tetracycline

Procedia PDF Downloads 188

Authors: Jihane Saad, Thomas Lendormi, Caroline Le Marechal, Anne-marie Pourcher, Céline Druilhe, Jean-louis Lanoiselle

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Agricultural anaerobic digestion consists in the conversion of animal slurry and manure into biogas and digestate. They need, however, to be treated at 70 ºC during 60 min before anaerobic digestion according to the European regulation (EC n°1069/2009 & EU n°142/2011). The impact of such heat treatment on the outcome of bacteria has been poorly studied up to now. Moreover, a recent study¹ has shown that enterococci and clostridia are still detected despite the application of such thermal treatment, questioning the relevance of this approach for the hygienisation of digestate. The aim of this study is to establish the heat inactivation kinetics of two species of enterococci (Enterococcus faecalis and Enterococcus faecium) and two species of clostridia (Clostridioides difficile and Clostridium novyi as a non-toxic model for Clostridium botulinum of group III). A pure culture of each strain was prepared in a specific sterile medium at concentration of 10⁴ – 10⁷ MPN / mL (Most Probable number), depending on the bacterial species. Bacterial suspensions were then filled in sterilized capillary tubes and placed in a water or oil bath at desired temperature for a specific period of time. Each bacterial suspension was enumerated using a MPN approach, and tests were repeated three times for each temperature/time couple. The inactivation kinetics of the four indicator bacteria is described using the Weibull model and the classical Bigelow model of first-order kinetics. The Weibull model takes biological variation, with respect to thermal inactivation, into account and is basically a statistical model of distribution of inactivation times as the classical first-order approach is a special case of the Weibull model. The heat treatment at 70 ºC / 60 min contributes to a reduction greater than 5 log10 for E. faecium and E. faecalis. However, it results only in a reduction of about 0.7 log10 for C. difficile and an increase of 0.5 log10 for C. novyi. Application of treatments at higher temperatures is required to reach a reduction greater or equal to 3 log10 for C. novyi (such as 30 min / 100 ºC, 13 min / 105 ºC, 3 min / 110 ºC, and 1 min / 115 ºC), raising the question of the relevance of the application of heat treatment at 70 ºC / 60 min for these spore-forming bacteria. To conclude, the heat treatment (70 ºC / 60 min) defined by the European regulation is sufficient to inactivate non-sporulating bacteria. Higher temperatures (> 100 ºC) are required as far as spore-forming bacteria concerns to reach a 3 log10 reduction (sporicidal activity).

Keywords: heat treatment, enterococci, clostridia, inactivation kinetics

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Authors: Mohammad Hossein Pazandeh, Monir Doudi, Sona Rostampour Yasouri

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Irregular consumption of current antibiotic makes increases of antibiotic resistance between urin pathogens on all worlds. This study selected based on this great community problem. The aim of this study was the biosynthesis of silver nanoparticles from Zataria multiflora extract and then to investigate its antibacterial effect on gram-negative bacilli common in Urinary Tract Infections (UTI) and MDR. The plant used in the present research was Zataria multiflora whose extract was prepared through Soxhlet extraction method. Green synthesis condition of silver nanoparticles was investigated in terms of three parameters including the extract amount, concentration of silver nitrate salt, and temperature. The seizes of nanoparticles were determined by Zetasizer. In order to identify synthesized silver nanoparticles Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) methods were used. For evaluating the antibacterial effects of nanoparticles synthesized through biological method different concentrations of silver nanoparticles were studied on 140 cases of Muliple Drug Resistance (MDR) bacteria strains Escherichia coli, Klebsiella pneumoniae, Enterobacter aerogenes, Proteus vulgaris,Citrobacter freundii, Acinetobacter bumanii and Pseudomonas aeruginosa, (each genus of bacteria, 20 samples), which all were MDR and cause urinary tract infections , for identification of bacteria were used of Polymerase Chain Reaction (PCR) test and laboratory methods (Agar well diffusion and Microdilution methods) to assess their sensitivity to Nanoparticles. The data were analyzed using SPSS software by nonparametric Kruskal-Wallis and Mann-Whitney tests. Significant results were found about the effects of silver nitrate concentration, different amounts of Zataria multiflora extract, and temperature on nanoparticles; that is, by increasing the concentration of silver nitrate, extract amount, and temperature, the sizes of synthesized nanoparticles declined. However, the effect of above mentioned factors on particles diffusion index was not significant. Based on the TEM results, particles were mainly spherical shape with a diameter range of 25 to 50 nm. The results of XRD Analysis indicated the formation of Nanostructures and Nanocrystals of silver.. The obtained results of antibacterial effects of different concentrations of silver nanoparticles on according to agar well diffusion and microdilution method, biologically synthesized nanoparticles showed 1000 mg /ml highest and lowest mean inhibition zone diameter in E.coli , Acinetobacter bumanii 23 and 15mm, respectively. MIC was observed for all of bacteria 125mg/ml and for Acinetobacter bumanii 250mg/ml.Comparing the growth inhibitory effect of chemically synthesized Nanoparticles and biologically synthesized Nanoparticles showed that in the chemical method the highest growth inhibition belonged to the concentration of 62.5 mg /ml. The inhibitory effect on the growth all of bacteria causes of urine infection and MDR was observed and by increasing silver ion concentration in Nanoparticles, antibacterial activity increased. Generally, the biological synthesis can be considered an efficient way not only in making Nanoparticles but also for having anti-bacterial properties. It is more biocompatible and may be possess less toxicity than the Nanoparticles synthesized chemically.

Keywords: biosynthesis, MDR bacteria, silver nanoparticles, UTI

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Authors: Amal Hussain Alkhaiwani, Ghadah Abdullah Almalki

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Recently human errors have increasingly become a very high factor in security breaches that may affect confidential data, and most of the cyber data breaches are caused by human errors. With one individual mistake, the attacker will gain access to the entire network and bypass the implemented access controls without any immediate detection. Unaware employees will be vulnerable to any social engineering cyber-attacks. Providing security awareness to People is part of the company protection process; the cyber risks cannot be reduced by just implementing technology; the human awareness of security will significantly reduce the risks, which encourage changes in staff cyber-awareness. In this paper, we will focus on Human Awareness, human needs to continue the required security education level; we will review human errors and introduce a proposed solution to avoid the breach from occurring again. Recently Saudi Arabia faced many attacks with different methods of social engineering. As Saudi Arabia has become a target to many countries and individuals, we needed to initiate a defense mechanism that begins with awareness to keep our privacy and protect the confidential data against possible intended attacks.

Keywords: cybersecurity, human aspects, human errors, human mistakes, security awareness, Saudi Arabia, security program, security education, social engineering

Procedia PDF Downloads 160

Authors: Zuliani Mahmood, Thirumulu Ponnuraj Kannan, Yean Yean Chan, Salahddin A. Al-Hudhairy

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Caries is the most common childhood disease which develops due to disturbances in the physiological equilibrium in the dental plaque resulting in demineralization of tooth structures. Plaque and dentine samples were collected from three different tooth surfaces representing caries progression (intact, over carious lesion and dentine) in children with early childhood caries (ECC, n=36). In caries free (CF) children, plaque samples were collected from sound tooth surfaces at baseline and after one year (n=12). The genomic DNA was extracted from all samples and subjected to 16S rRNA PCR amplification. The end products were cloned into pCR®2.1-TOPO® Vector. Five randomly selected positive clones collected from each surface were sent for sequencing. Identification of the bacterial clones was performed using BLAST against GenBank database. In the ECC group, the frequency of Lactobacillus sp. detected was significantly higher in the dentine surface (p = 0.031) than over the cavitated lesion. The highest frequency of bacteria detected in the intact surfaces was Fusobacterium nucleatum subsp. polymorphum (33.3%) while Streptococcus mutans was detected over the carious lesions and dentine surfaces at a frequency of 33.3% and 52.7% respectively. Fusobacterium nucleatum subsp. polymorphum was also found to be highest in the CF group (41.6%). Follow up at the end of one year showed that the frequency of Corynebacterium matruchotii detected was highest in those who remained caries free (16.6%), while Porphyromonas catoniae was highest in those who developed caries (25%). In conclusion, Streptococcus mutans and Porphyromonas catoniae are strongly associated with caries progression, while Lactobacillus sp. is restricted to deep carious lesions. Fusobacterium nucleatum subsp. polymorphum and Corynebacterium matruchotii may play a role in sustaining the healthy equilibrium in the dental plaque. These identified bacteria show promise as potential biomarkers in diagnosis which could help in the management of dental caries in children.

Keywords: early childhood caries, genotypic identification, oral bacteria, 16S rRNA

Procedia PDF Downloads 275

Authors: Blen Telayneh Melese

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Rural development, the unending quest of a developing country, cannot be succeeded in deprived of human capital development. Human capital, the economic pillars of a country's development, appeals a policy-based supports while fulfilling what is expected. Ethiopia, one of the rural countries with untouched and forgotten land and human force, owes historical experiences of educational policy intending for mobilization of its citizen for the advancement of the overall economy. Rural Ethiopia as well has been the focus of those educational policies, considering the economic resources entrenched with in. In this literature review paper, Ethiopian educational policy and its contribution to human capital development, as well as its role in generating quality human labor force, is assessed concisely. The author argues that the foundation of rural development such as technology, knowledge, infrastructure, market chain, communication and etc., can only be achieved through enhanced education policy that conciliates the existing reality of rural communities. Ethiopia still needs an education policy that enables it to generate a human capital that is oriented with the rural areas economic opportunities and challenges.

Keywords: Ethiopia, rural development, human capital development, education policy

Procedia PDF Downloads 359

Authors: Sonya Barzgar, J. Patrick, A. Hettiaratchi

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Methane (CH4) is reputed as the second largest contributor to greenhouse effect with a global warming potential (GWP) of 34 related to carbon dioxide (CO2) over the 100-year horizon, so there is a growing interest in reducing the emissions of this gas. Methane biofiltration (MBF) is a cost effective technology for reducing low volume point source emissions of methane. In this technique, microbial oxidation of methane is carried out by methane-oxidizing bacteria (methanotrophs) which use methane as carbon and energy source. MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting methane to carbon dioxide (CO₂) and water (H₂O). Even though the biofiltration technique has been shown to be an efficient, practical and viable technology, the design and operational parameters, as well as the relevant microbial processes have not been investigated in depth. In particular, limited research has been done on the effects of sulphur on methane bio-oxidation. Since bacteria require a variety of nutrients for growth, to improve the performance of methane biofiltration, it is important to establish the input quantities of nutrients to be provided to the biofilter to ensure that nutrients are available to sustain the process. The study described in this paper was conducted with the aim of determining the influence of sulphur on methane elimination in a biofilter. In this study, a set of experimental measurements has been carried out to explore how the conversion of elemental sulphur could affect methane oxidation in terms of methanotrophs growth and system pH. Batch experiments with different concentrations of sulphur were performed while keeping the other parameters i.e. moisture content, methane concentration, oxygen level and also compost at their optimum level. The study revealed the tolerable limit of sulphur without any interference to the methane oxidation as well as the particular sulphur concentration leading to the greatest methane elimination capacity. Due to the sulphur oxidation, pH varies in a transient way which affects the microbial growth behavior. All methanotrophs are incapable of growth at pH values below 5.0 and thus apparently are unable to oxidize methane. Herein, the certain pH for the optimal growth of methanotrophic bacteria is obtained. Finally, monitoring methane concentration over time in the presence of sulphur is also presented for laboratory scale biofilters.

Keywords: global warming, methane biofiltration (MBF), methane oxidation, methanotrophs, pH, sulphur

Procedia PDF Downloads 236