Biodegradation of chloroethene compounds under microoxic conditions.

The biodegradation of chloroethene compounds under oxic and anoxic conditions is well established. However, the biological reactions that take place under microoxic conditions are unknown. Here, we report the biostimulated (BIOST: addition of lactate) and natural attenuated (NAT) degradation of chloroethene compounds under microoxic conditions by bacterial communities from chloroethene compounds-contaminated groundwater. The degradation of tetrachloroethene was significantly higher in NAT (15.14% on average) than in BIOST (10.13% on average) conditions at the end of the experiment (90 days). Sporomusa, Paracoccus, Sedimentibacter, Pseudomonas, and Desulfosporosinus were overrepresented in NAT and BIOST compared to the source groundwater. The NAT metagenome contains phenol hydrolase P1 oxygenase (dmpL), catechol-1,2-dioxygenase (catA), catechol-2,3-dioxygenases (dmpB, todE, and xylE) genes, which could be involved in the cometabolic degradation of chloroethene compounds; and chlorate reductase (clrA), that could be associated with partial reductive dechlorination of chloroethene compounds. Our data provide a better understanding of the bacterial communities, genes, and pathways potentially implicated in the reductive and cometabolic degradation of chloroethene compounds under microoxic conditions.

A metagenomic survey of the fecal microbiome of the African savanna elephant (Loxodonta africana).

The African savanna elephant (Loxodonta africana) is the largest terrestrial animal on Earth and is found primarily in Southern and Eastern Africa. It is a hindgut, colonic fermenter and subsists on a diet of raw plant materials found in its grazing area. In this study the bacterial, archaeal and fungal populations of seven African savanna elephant fecal metagenomes were first characterized using amplicon sequencing. On the genus level it was observed that the p-1088-a5 gut group in the bacteriome, Methanocorpusulum and Methanobrevibacter in the archaeome and Alternaria, Aurobasidium, Didymella and Preussia in the mycome, predominated. Subsequently, metagenomic shotgun sequencing was employed to identify possible functional pathways and carbohydrate-active enzymes (CAZymes). Carbohydrate catabolic pathways represented the main degradation pathways, and the fecal metagenome was enriched in the glycohydroside (GH) class of CAZymes. Additionally, the top GH families identified - GH43, GH2, GH13 and GH3 - are known to be associated with cellulytic, hemicellulytic and pectolytic activities. Finally, the CAZymes families identified in the African savanna elephant were compared with those found in the Asian elephant and it was demonstrated that there is a unique repository of CAZymes that could be leveraged in the biotechnological context such as the degradation of lignocellulose for the production of second-generation biofuels and energy.

Application of solid-state fermentation using mushrooms for the production of animal feed.

The increasing growth of agroindustrial activity resulting in excessive amounts of agriwaste has led to the accumulation of a large quantity of lignocellulosic residues all over the world, in particular in deforestation initiatives for the removal of invasive trees in South Africa. These lignocellulosic residues are rich in energy resources and consist of a mixture of natural polymers based on lignin, cellulose, and hemicellulose. The use of lignolytic fungi such as mushrooms in solid-state fermentation could sufficiently degrade the indigestible lignocellulosic components and add medicinal and nutritional value to otherwise unusable, high-energy waste material, which in turn could yield a new method of producing energy-rich fodder for ruminant animals. The digestive type of animal for which the potential feed is developed must be identified and considered before deciding on the bioconversion method and process, as the outcomes for obtaining potentially high-quality feeds for nonruminant and ruminant animals are different. The current study presents data on the bioconversion of lignocellulosic substrate using solid-state fermentation with edible and medicinal mushrooms, Ganoderma lucidumand Pleurotus ostreatus, and a possible new species, to increase digestibility and nutritional value to be applied as ruminant animal feed. The solid-state fermentation process was optimized and the resulting product was analyzed for the degradation of the lignocellulosic components. Results indicated that the solid-state fermentation duration and mushroom species were key components in achieving significant degradation. Data obtained after 18 weeks of degradation indicated a significant (p < 0.05) reduction in the acid detergent fiber, acid detergent lignin, and neutral detergent fiber fractions of the biomass, with up to a 20% reduction in indigestible components. This increase in digestibility could contribute to increased energy availability for ruminant animals.

Novel lichen-dominated hypolithic communities in the Namib Desert.

The ventral surfaces of translucent rocks from hot desert pavements often harbor hypolithic microbial communities, which are mostly dominated by cyanobacteria. The Namib Desert fog belt supports extensive hypolithic colonization of quartz rocks, which are also colonized by lichens on their dorsal surfaces. Here, we aim to evaluate whether lichens colonize the ventral surface of the rocks (i.e., show hypolithic lifestyle) and compare the bacterial composition of these coastal hypolithic communities with those found inland. Fungal DNA barcoding and fungal and bacterial Illumina metabarcoding were combined with electron microscopy to characterize the composition and spatial structure of hypolithic communities from two (coastal and inland) areas in the Namib Desert. We report, for the first time, the structure and composition of lichen-dominated hypolithic communities found in the coastal zone of the Namib Desert with extensive epilithic lichen cover. Lichen modified areoles with inverted morphology of the genus Stellarangia (three lineages) and Buellia (two lineages) were the main components of these hypolithic communities. Some of these lineages were also found in epilithic habitats. These lichen-dominated hypolithic communities differed in structural organization and bacterial community composition from those found in inland areas. The hypolithic lichen colonization characterized here seems not to be an extension of epilithic or biological soil crust lichen growths but the result of specific sublithic microenvironmental conditions. Moisture derived from fog and dew could be the main driver of this unique colonization.

FISH-TAMB, a Fixation-Free mRNA Fluorescent Labeling Technique to Target Transcriptionally Active Members in Microbial Communities.

Keystone species or ecological engineers are vital to the health of an ecosystem; however, often, their low abundance or biomass present challenges for their discovery, identification, visualization and selection. We report the development of fluorescent in situ hybridization of transcript-annealing molecular beacons (FISH-TAMB), a fixation-free protocol that is applicable to archaea and bacteria. The FISH-TAMB method differs from existing FISH methods by the absence of fixatives or surfactants in buffers, the fast hybridization time of as short as 15 min at target cells' growth temperature, and the omission of washing steps. Polyarginine cell-penetrating peptides are employed to deliver molecular beacons (MBs) across prokaryotic cell walls and membranes, fluorescently labeling cells when MBs hybridize to target mRNA sequences. Here, the detailed protocol of the preparation and application of FISH-TAMB is presented. To demonstrate FISH-TAMB's ability to label intracellular mRNA targets, differentiate transcriptional states, detect active and rare taxa, and keep cell viability, labeling experiments were performed that targeted the messenger RNA (mRNA) of methyl-coenzyme M reductase A (mcrA) expressed in (1) Escherichia coli containing a plasmid with a partial mcrA gene of the methanogen Methanosarcina barkeri (E. coli mcrA+); (2) M. barkeri; and (3) an anaerobic methanotrophic (ANME) enrichment from a deep continental borehole. Although FISH-TAMB was initially envisioned for mRNA of any functional gene of interest without a requirement of prior knowledge of 16S ribosomal RNA (rRNA)-based taxonomy, FISH-TAMB has the potential for multiplexing and going beyond mRNA and thus is a versatile addition to the molecular ecologist's toolkit, with potentially widespread application in the field of environmental microbiology.

Pollution shapes the microbial communities in river water and sediments from the Olifants River catchment, South Africa.

Human activities such as agriculture and mining are leading causes of water pollution worldwide. Individual contaminants are known to negatively affect microbial communities. However, the effect of multifaceted pollution on these communities is less well understood. We investigated, using next-generation sequencing of the 16S rRNA genes, the effects of multisource (i.e., fertilizer industry and mining) chronic pollution on bacterial and archaeal communities in water and sediments from the Olifants River catchment, South Africa. Water samples showed less microbial species diversity than sediments and both habitats displayed different microbial communities. Within each of these habitats, pollution had no effect on alpha diversity but shaped the microbial composition and taxonomy-based predicted functions. Certain prokaryotic taxa and functional groups were indicative of different degrees of pollution. Heterotrophic taxa (e.g., Flavobacterium sp.) and sulphur-oxidizing bacteria (i.e., Thiobacillus sp.) were indicators of pollution in water and sediments, respectively. Ultimately, this information could be used to develop microbial indicators of water quality degradation.

Aerobic and anaerobic enrichment cultures highlight the pivotal role of facultative anaerobes in soil hydrocarbon degradation.

Aliphatic and aromatic hydrocarbons are ubiquitous in the environment due to natural and anthropogenic processes. Under aerobic conditions hydrocarbons can be rapidly biodegraded but oxygenated environments often quickly become anaerobic when microbial respiration is coupled to contaminant oxidation. Most studies in literature usually focus on the initial microbial diversity of the hydrocarbon impacted environment and examine either aerobic or anaerobic conditions for enrichment. Hence, the aim of the present study was to enrich bacterial consortiums from two diesel impacted soil samples under both these conditions to assess the enrichment diversities and hydrocarbon degradation potentials. This would shed light upon how an environmental population shift would correlate to oxygen intrusion and depletion and still continue hydrocarbon degradation. Analysis of the 16S rRNA gene sequences showcases the different microbial populations that could emerge as the environmental factors change, resulting in different populations that are still capable of hydrocarbon degradation. Microbial diversity analysis also highlights the role of facultative anaerobic bacteria like Pseudomonas spp. and Citrobacter spp. in maintaining hydrocarbon degradation. This study shows that microorganisms capable of surviving under both oxic and anoxic (aerobic and anaerobic) conditions are the most crucial to the long term degradation of hydrocarbons in the environment.

Evaluation of in vitro refolding vs cold shock expression: Production of a low yielding single chain variable fragment.

The development of therapeutic antibodies in their various forms has been a constant challenge since the development of the first monoclonal antibodies in 1975. This is especially true for the development of therapeutic single chain variable (scFv) fragments in Escherichia coli. In a previous study the selection of a tissue factor inhibiting single chain variable fragment (TFI-scFv) isolated from the Thomlinson I + J phage libraries was described. Although the initial findings were promising, additional characterization of the antibody fragment and subsequent application was hampered due low protein yield. This study reports on: i) the improved expression of a previously low yielding TFI-scFv in the cytoplasm of E. coli BL21 (DE3) through modifications to the expression systems in conjunction with codon optimization ii) evaluation of two commercial methods of protein recovery: in vitro refolding and the utilization of cold shock expression systems in conjunction with E. coli SHuffle. Results showed that TFI-scFv could be expressed at higher levels in the cytoplasm of E. coli than previously achieved in the periplasm. Both the in vitro refolding and cold shock strategies were capable of producing functional TFI-scFv with varying degrees of success. These procedures could be applied to improve the production of other problematic low yielding scFv isolated from phage display repositories in order to facilitate their characterization.

Sporosalibacterium tautonense sp. nov., a thermotolerant, halophilic, hydrolytic bacterium isolated from a gold mine, and emended description of the genus Sporosalibacterium.

A novel strictly anaerobic, thermotolerant, moderately halophilic, organotrophic bacterium, strain MRo-4T, was isolated from a sample of a microbial mat, developed under the flow of subsurface water in TauTona gold mine, South Africa. Cells of the novel isolate stained Gram-positive and were motile, spore-forming rods, 0.2-0.3 µm in width and 5-20 µm in length. Strain MRo-4T grew at 25-50 °C, at pH 7.0-8.8 and at an NaCl concentration of 5-100 g l-1. The isolate was able to ferment yeast extract, peptone and mono-, oligo- and polysaccharides, including cellulose and chitin. Elemental sulfur, thiosulfate, sulfate, sulfite, nitrate, nitrite, fumarate and arsenate were not reduced. The major fatty acids were iso-C15 : 0, iso-C15 : 0 dimethyl acetyl and anteiso-C15 : 0. The G+C content of the DNA was 32.9 mol%. Phylogenetic analysis of 16S rRNA gene sequences of strain MRo-4T and its nearest relatives showed its affiliation to the genus Sporosalibacterium. Sporosalibacteriumfaouarense SOL3f37T, the only valid published representative of the genus, appeared to be its closest relative (96.8 % 16S rRNA gene sequence similarity). However, strains MRo-4T and S. faouarense SOL3f37T differed in temperature, pH and salinity ranges for growth, requirement for yeast extract and substrate profiles. Based on the phylogenetic analysis and physiological properties of the novel isolate, we propose a novel species, Sporosalibacterium tautonense sp. nov. The type strain is MRo-4T (=DSM 28179T=VKM B-2948T).

Hexavalent chromium bioreduction and chemical precipitation of sulphate as a treatment of site-specific fly ash leachates.

Most of the power generation globally is by coal-fired power plants resulting in large stockpiles of fly ash. The trace elements associated with the ash particles are subjected to the leaching effects of precipitation which may lead to the subsequent contamination of surface and groundwater systems. In this study, we successfully demonstrate an efficient and sustainable dual treatment remediation strategy for the removal of high levels of Cr6+ and SO42- introduced by fly ash leachate generated by a power station situation in Mpumalanga, South Africa. The treatment consisted of a primary fixed-bed bioreactor kept at a reduction potential for Cr6+ reduction. Metagenome sequencing clearly indicated a diverse bacterial community containing various bacteria, predominantly of the phylum Proteobacteria which includes numerous species known for their ability to detoxify metals such as Cr6+. This was followed by a secondary BaCO3/dispersed alkaline substrate column for SO42- removal. The combination of these two systems resulted in the removal of 99% Cr6+ and 90% SO42-. This is the first effective demonstration of an integrated system combining a biological and chemical strategy for the remediation of multi-contaminants present in fly ash leachate in South Africa.

Tepidibacillus infernus sp. nov., a moderately thermophilic, selenate- and arsenate-respiring hydrolytic bacterium isolated from a gold mine, and emended description of the genus Tepidibacillus.

A novel aerotolerant anaerobic, moderately thermophilic, organotrophic bacterium, strain MBL-TLPT, was isolated from a sample of microbial mat, developed under the flow of subsurface water in TauTona gold mine, South Africa. Cells of the new isolate were flagellated, spore-forming rods, 0.25-0.5 µm in width and 3-15 µm in length. Strain MBL-TLPT grew in the temperature range from 25 to 58 °C, pH range from 5.6 to 8.8 and at NaCl concentration from 0 to 85 g l-1. The isolate was able to ferment yeast extract and mono-, oligo- and polysaccharides, including starch and xanthan gum. The G+C content of the DNA was 35 mol%. Phylogenetic analysis of 16S rRNA gene sequences of strain MBL-TLPT and relatives showed its affiliation to the genus Tepidibacillus. Tepidibacillus fermentans STGHT was its closest relative (97.1 % identity of 16S rRNA gene sequences). Based on phylogenetic analysis and the physiological properties of the novel isolate, we propose a novel species, Tepidibacillus infernus sp. nov., with MBL-TLPT(=DSM 28123T=VKM В-2949T) as the type strain.

Characterization of Microbial Diversity of Two Tomato Cultivars through Targeted Next-Generation Sequencing 16S rRNA and ITS Techniques.

Even though the nutritional and economic values of Solanum lycopersicum (tomato) are substantially impacted by microbial spoilage, the available data on its microbial community, particularly during spoilage, are limited and have primarily been characterized using conventional culture-dependent methods. This study employed a targeted high-throughput next-generation sequencing method to longitudinally characterize the microbial diversity of two South African tomato cultivars (jam and round) at varied storage intervals (1, 6, and 12 days). Throughout the storage period, the bacterial communities of the two cultivars were more diverse than the fungal communities. The microbial diversity of both bacteria and fungi was greater and comparable between the cultivars on day 1, but becomes distinct as the storage period increases, with round tomatoes being more diverse than jam tomato, though, on day 12, jam tomato develops greater diversity than round tomato. Overall, the most abundant phyla (though Proteobacteria was most dominant) were Proteobacteria, Firmicutes, and Bacteriodota in the bacterial communities, while Ascomycota and Basidiomycota formed most fungal communities with Ascomycota being dominant. At the genus level, Pantoea and Klebsiella (bacteria), Hanseniaspora, Stemphylium, and Alternaria (fungi) were prevalent. Taken together, this study casts light on a broad microbial diversity profile thus, confirms the cultivars' diversity and abundance differences.

Chemical Characterization and Metagenomic Identification of Endophytic Microbiome from South African Sunflower (Helianthus annus) Seeds.

Helianthus annus (sunflower) is a globally important oilseed crop whose survival is threatened by various pathogenic diseases. Agrochemical products are used to eradicate these diseases; however, due to their unfriendly environmental consequences, characterizing microorganisms for exploration as biocontrol agents are considered better alternatives against the use of synthetic chemicals. The study assessed the oil contents of 20 sunflower seed cultivars using FAMEs-chromatography and characterized the endophytic fungi and bacteria microbiome using Illumina sequencing of fungi ITS 1 and bacteria 16S (V3-V4) regions of the rRNA operon. The oil contents ranged between 41-52.8%, and 23 fatty acid components (in varied amounts) were found in all the cultivars, with linoleic (53%) and oleic (28%) acids as the most abundant. Ascomycota (fungi) and Proteobacteria (bacteria) dominated the cultivars at the phyla level, while Alternaria and Bacillus at the genus level in varying abundance. AGSUN 5102 and AGSUN 5101 (AGSUN 5270 for bacteria) had the highest fungi diversity structure, which may have been contributed by the high relative abundance of linoleic acid in the fatty acid components. Dominant fungi genera such as Alternaria, Aspergillus, Aureobasidium, Alternariaste, Cladosporium, Penicillium, and bacteria including Bacillus, Staphylococcus, and Lactobacillus are established, providing insight into the fungi and bacteria community structures from the seeds of South Africa sunflower.

Radiolytically reworked Archean organic matter in a habitable deep ancient high-temperature brine.

Investigations of abiotic and biotic contributions to dissolved organic carbon (DOC) are required to constrain microbial habitability in continental subsurface fluids. Here we investigate a large (101-283 mg C/L) DOC pool in an ancient (>1Ga), high temperature (45-55 °C), low biomass (102-104 cells/mL), and deep (3.2 km) brine from an uranium-enriched South African gold mine. Excitation-emission matrices (EEMs), negative electrospray ionization (-ESI) 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amino acid analyses suggest the brine DOC is primarily radiolytically oxidized kerogen-rich shales or reefs, methane and ethane, with trace amounts of C3-C6 hydrocarbons and organic sulfides. δ2H and δ13C of C1-C3 hydrocarbons are consistent with abiotic origins. These findings suggest water-rock processes control redox and C cycling, helping support a meagre, slow biosphere over geologic time. A radiolytic-driven, habitable brine may signal similar settings are good targets in the search for life beyond Earth.

Plant and Soil Core Mycobiomes in a Two-Year Sorghum-Legume Intercropping System of Underutilized Crops in South Africa.

Fungal communities form close beneficial (mutualists) or detrimental (pathogens) associations with their plant hosts. Their diversity and abundance can be affected by agricultural practices which include cropping systems such as rotations and intercropping. Despite the importance of cropping systems in increasing productivity, knowledge of the fungal mycobiome and the core inhabitants for under-utilised cereal and legume crops, particularly over a period, is still limited. The core mycobiomes in plant tissues and bulk soils of a cereal-legume intercrop were characterized over two years using high-throughput sequencing. The intercropping trial consisted of sorghum, Bambara groundnut, cowpea, dry bean, and soybean. A greater number of molecular operational taxonomic units (MOTUs) were found in plant tissues compared to those from the soils and between year one and year two. Principal coordinate analyses revealed that fungal communities for each year were relatively distinct, particularly for the soils. The core mycobiome was dominated by a Davidiellaceae sp. (Cladosporium), Didymellaceae sp. 1 (Phoma), Didymellaceae sp. 2 (Epicoccum), Fusarium sp. 2, Unidentified (Ascomycota), and Cryptococcus MOTUs that were present in all plant tissues and soils of year one and two. Other key MOTUs were only specific to a year, substrate, or crop. Although the mycobiome of sorghum were more distinct than the cores of the legumes, there were still MOTUs dominant across all of the crops. Characterization of this baseline core across two years provides insight into those fungi that are always present in these crops, and that could be utilized in improving crop performance and productivity.

Transcriptional response of Candida albicans to Pseudomonas aeruginosa in a polymicrobial biofilm.

Candida albicans is frequently co-isolated with the Gram-negative bacterium, Pseudomonas aeruginosa. In vitro, the interaction is complex, with both species influencing each other. Not only does the bacterium kill hyphal cells of C. albicans through physical interaction, it also affects C. albicans biofilm formation and morphogenesis, through various secreted factors and cell wall components. The present study sought to expand the current knowledge regarding the interaction between C. albicans and P. aeruginosa, using transcriptome analyses of early static biofilms. Under these conditions, a total of 2,537 open reading frames (approximately 40% of the C. albicans transcriptome) was differentially regulated in the presence of P. aeruginosa. Upon deeper analyses it became evident that the response of C. albicans toward P. aeruginosa was dominated by a response to hypoxia, and included those associated with stress as well as iron and zinc homeostasis. These conditions may also lead to the observed differential regulation of genes associated with cell membrane synthesis, morphology, biofilm formation and phenotypic switching. Thus, C. albicans in polymicrobial biofilms with P. aeruginosa have unique transcriptional profiles that may influence commensalism as well as pathogenesis.

Baseline Data of the Fungal Phytobiome of Three Sorghum (Sorghum bicolor) Cultivars in South Africa using Targeted Environmental Sequencing.

Plant-associated fungi, or the mycobiome, inhabit plant surfaces above ground, reside in plant tissues as endophytes, or are rhizosphere in the narrow zone of soil surrounding plant roots. Studies have characterized mycobiomes of various plant species, but little is known about the sorghum mycobiome, especially in Africa, despite sorghum being one of the most important indigenous and commercial cereals in Africa. In this study, the mycobiome associated with above- and below-ground tissues of three commercial sorghum cultivars, as well as from rhizosphere and surrounding bulk soil samples, were sequenced using targeted sequencing with the Illumina MiSeq platform. Relative abundance differences between fungal communities were found between above-ground and below-ground niches, with most differences mostly in the dominant MOTUs, such as Davidiellaceae sp. (Cladosporium), Didymellaceae sp. 1 (Phoma), Fusarium, Cryptococcus and Mucor. Above-ground communities also appeared to be more diverse than below-ground communities, and plants harboured the most diversity. A considerable number of MOTUs were shared between the cultivars although, especially for NS5511, their abundances often differed. Several of the detected fungal groups include species that are plant pathogens of sorghum, such as Fusarium, and, at low levels, Alternaria and the Ustilaginomycetes. Findings from this study illustrate the usefulness of targeted sequencing of the ITS rDNA gene region (ITS2) to survey and monitor sorghum fungal communities and those from associated soils. This knowledge may provide tools for disease management and crop production and improvement.

A clinically important, plasmid-borne antibiotic resistance gene (ß-lactamase TEM-116) present in desert soils.

The exhaustive use of antibiotics in humans, animal farming and other agricultural practices has resulted in the frequent appearance of antibiotic resistant bacteria in human-impacted habitats. However, antibiotic resistance in natural (less-impacted) habitats is less understood. Using shotgun metagenomics we analysed soils from relatively low anthropogenic impact sites across the Namib Desert. We report the presence of a clinically significant extended spectrum ß-lactamase (TEM-116), on a ColE1-like plasmid also carrying a metal resistance gene (arsC). The co-occurrence of resistance to antimicrobial drugs and metals encoded on a single mobile genetic element increases the probability of dissemination of these resistance determinants and the potential selection of multiple resistance mechanisms. In addition, the presence of a P7 entero-bacteriophage on the same plasmid, may represent a new vehicle for the propagation of TEM-116 in these soil communities. These findings highlight the role of the environment in the One Health initiative.

Transcriptome Analyses of Candida albicans Biofilms, Exposed to Arachidonic Acid and Fluconazole, Indicates Potential Drug Targets.

Candida albicans is an opportunistic yeast pathogen within the human microbiota with significant medical importance because of its pathogenic potential. The yeast produces highly resistant biofilms, which are crucial for maintaining infections. Though antifungals are available, their effectiveness is dwindling due to resistance. Alternate options that comprise the combination of existing azoles and polyunsaturated fatty acids, such as arachidonic acid (AA), have been shown to increase azoles susceptibility of C. albicans biofilms; however, the mechanisms are still unknown. Therefore, transcriptome analysis was conducted on biofilms exposed to sub-inhibitory concentrations of AA alone, fluconazole alone, and AA combined with fluconazole to understand the possible mechanism involved with the phenomenon. Protein ANalysis THrough Evolutionary Relationships (PANTHER) analysis from the differentially expressed genes revealed that the combination of AA and fluconazole influences biological processes associated with essential processes including methionine synthesis and those involved in ATP generation, such as AMP biosynthesis, fumarate metabolism and fatty acid oxidation. These observations suggests that the interference of AA with these processes may be a possible mechanisms to induce increased antifungal susceptibility.

Bacterial and Fungal Dynamics During the Fermentation Process of Sesotho, a Traditional Beer of Southern Africa.

Sesotho is an indigenous cereal-based fermented drink traditionally produced in the mountain kingdom of Lesotho, Southern Africa. The present study sought to examine the microbial (bacterial and fungal) community composition of Sesotho at five fermentation stages in five different locations. Using culture-independent (Illumina sequencing) techniques it was found that the bacterial communities followed similar successional patterns during the fermentation processes, regardless of geographical location and recipe variation between breweries. The most abundant bacterial taxa belonged to the phyla Firmicutes (66.2% of the reads on average) and Proteobacteria (22.1%); the families Lactobacillaceae (54.9%), Enterobacteriaceae (14.4%) and Leoconostrocaceae (8.1%); and the genera Lactobacillus (54%), Leuconostoc (10.7%), Leptotrichia (8.5%), and Weissella (5.5%). Most fungal taxa were from the phyla Ascomycota (60.7%) and Mucoromycota (25.3%); the families Rhizopodaceae (25.3%), Nectriaceae (24.2%), Saccharomycetaceae (16%) and Aspergillaceae (6.7%); and the genera Rhizopus (25.3%), Saccharomyces (9.6%), and Aspergillus (2.5%). Lactic acid bacteria (LAB) such as Enterococcus, Pediococcus, Lactobacillus, Leuconostoc, and Wiesella; as well as yeasts belonging to the genus Saccharomyces, were dominant in all breweries during the production of Sesotho. Several pathogenic and food spoilage microorganisms (e.g., Escherichia, Shigella, Klebsiella, etc.) were also present, but the study demonstrated the safety potential of the Sesotho fermentation process, as these microbial groups decline throughout Sesotho production. The functional profiles of the different brewing steps showed that the process is dominated by chemoheterotrophic and fermentative metabolisms. This study reveals, for the first time, the complex microbial dynamics that occur during Sesotho production.