Influences of geochemical factors and substrate availability on Gram-positive and Gram-negative bacterial distribution and bio-processes in ageing municipal landfills

International Microbiology - Bacteria are primary agents of organic substrate metabolisation and elemental cycling in landfills. Two major bacterial groups, namely, Gram-positive (GP) and...     

Exploring the application of biostimulation strategy for bacteria in the bioremediation of industrial effluent

The purpose of this study was to isolate and characterise toxic element-resistant bacteria from acid mine drainage water and to apply them in the bioremediation of industrial effluent, as well as to identify optimal effluent:nutrient concentration for onsite biostimulation strategy. Wastewater samples were collected from acid mine drainage and industry. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was employed for elemental composition analysis. Isolated bacterial strains were characterised using molecular methods. Bioremediation assays were employed to determine the extent of bacterial tolerance and removal of toxic elements using a biostimulation strategy employing minimal salt medium (MSM) at varied concentrations and positive and negative controls of only MSM and industrial effluent, respectively. Two bacterial strains demonstrated resistance to toxic elements, Bacillus sp. MGI101 and Lysinibacillus sp. MGI102 both isolated from the AMD sites. However, no observable growth of toxic metal-resistant bacteria was obtained from the industrial effluents. Bacterial strains MGI101 and MGI102 demonstrated high resistance to target toxic elements during the screening and tolerance assays. Remarkably, Bacillus sp. MGI101 demonstrated greater ability to remove toxic elements including arsenic, chromium, zinc, copper and aluminium in undiluted solutions of the industrial effluent, with its highest removal capacity observed at > 60% for arsenic and aluminium. Both Bacillus sp.MGI101 and Lysinibacillus sp. MGI102 demonstrated varied abilities for the removal of toxic elements from dilution concentration of effluent mixed with MSM. However, the optimal dilution ratio observed in this experiment was 5:15 (effluent:MSM). Overall results demonstrated that isolated bacterial strains have the potential to be employed in bioremediation programmes of acid mine drainages and multi-element contaminated water.

     

Industrial wastewaters harbor a unique diversity of bacterial communities revealed by high-throughput amplicon analysis

Industrial wastewater effluents present a major source of water pollution, and can potentially alter the microbial ecological landscape. While there are numerous reports on the microbial quality of domestic municipal effluents and their perceived environmental effects, there are limited reports devoted to the study of bacterial diversity of effluents from individual industries before they are mixed up with other sources. This study analyzed both the physicochemical parameters and bacterial community structures of different industrial wastewaters using Illumina high-throughput sequencing platform. Industrial wastewater with temperature ranging from 18.9 to 21.5 °C, and total dissolved solid (TDS) levels at up to 4611 mg/L, appeared to be predominated by Proteobacteria (44.44–75.86%) with the exception of the Capegate sample where Actinobacteria (39.66%) were the highest. Sulfur levels were significantly higher (p?<?0.05) in Dixon wastewater constituting higher populations of sulfur reducing bacteria (SRB) compared to the other sites. Diversity index (Shannon-H index) and richness estimator (Chao1 index) ranged from 974 (Capegate) to 4552 (Dixon) and 6.04 (Dixon) to 4.15 (CWI), respectively. Multivariate analysis results highlighted that the bacterial communities were strongly shaped by physicochemical variables. The top 10 operational taxonomic units (OTUs) of each industrial sample had the potential to play important roles in the bioremediation and biodegradation of pollutants. Dominant OTUs belonging to the phyla Planctomyces from the Chemreem sample could not be classified to any genera and are likely to represent novel species.     

Synthetic extreme environments: overlooked sources of potential biotechnologically relevant microorganisms

Synthetic extreme environments like carwash effluent tanks and drains are potential sources of biotechnologically important microorganisms and molecules which have, however, remained unexplored. Using culture‐ and molecular‐based methods, a total of 17 bacterial isolates belonging to the genera Shewanella, Proteus, Paenibacillus, Enterobacter and Citrobacter, Aeromonas, Pseudomonas and Pantoea were identified. Hydrocarbon utilization and enzyme production screening assays showed that Aeromonas sp. CAC11, Paenibacillus sp. CAC12 and Paenibacillus sp. CAC13 and Citrobacter sp. PCW7 were able to degrade benzanthracene, naphthalene and diesel oil, Paenibacillus sp. CAC12 and Paenibacillus sp. CAC13 could produce cellulase enzyme, while Proteus sp. BPS2, Pseudomonas sp. SAS8 and Proteus sp. CAL3 could produce lipase. GC‐MS analysis of bacterial secondary metabolites resulted in identification of 107 different compounds produced by Proteus sp. BPS2, Paenibacillus sp. CAC12, Pseudomonas sp. SAS8, Proteus sp. CAL3 and Paenibacillus sp. CAC13. Most of the compounds identified by both GC‐MS and LC‐MS have previously been determined to have antibacterial, antifungal and/or anticancer properties. Further, microbial metabolites which have previously been known to be produced only by plants or microorganisms found in natural extreme environments were also identified in this study. This research has revealed the immense bioresource potential of microorganisms inhabiting synthetic extreme environments.     

Winter Planktonic Microbial Communities in Highland Aquatic Habitats

Winter conditions in aquatic habitats of the temperate zone markedly differ from those present in warmer seasons, nevertheless, relatively scarce information is available on planktonic microbial composition, as sites are not easily accessible and it was supposed traditionally that microbial activity is low during this cold period. Since microorganisms could have great impact on the ecosystem even during winter, we explored various sites in the Eastern Carpathians regarding the abundance and taxonomic composition of planktonic microorganisms. Although many of the studied environments were extreme habitats, planktonic microbial communities were abundant and mostly diverse with the presence of previously unidentified taxa.     

Comparative metagenomics and functional profiling of crude oil-polluted soils in Bodo West Community,Ogoni, with other sites of varying pollution history

The impact of long-term crude oil pollution on soil microbial community structure in Bodo West Community, Ogoniland, Nigeria, was investigated to determine the amenability of the soil to microbial mediated remediation. Crude oil-polluted and pristine soil samples were collected approximately from 0 to 30 cm depth for both chemical and microbiological analyses. Total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAH) were determined using gas chromatograph–mass spectrophotometer (GC-MS). The soil microbiome was determined using the Illumina MiSeq platform. Results from this study were then compared with publicly available data from other oil-polluted sites. Taxonomic biomarkers and pathways associated with oil-polluted soils were detected using bioinformatics pipelines. TPH in the polluted and pristine soils were 7591 mg/kg and 199.70 mg/kg respectively, while the values of PAHs were significantly higher (p < 0.05) in the oil-polluted soil. Predictive functional and biomarker analysis demonstrated that microbes detected in the oil-polluted environment were involved in different metabolic pathways for degradation of a broad set of xenobiotic aromatic compounds. Established hydrocarbon degraders belonging to the families Alcanivoracaceae and Oceanospirillaceae were mostly detected in the oil-polluted soils. Sneathiella, Parvibaculum, Sphingobium, and Oceanicaulis were among biomarker taxa. The bacterial families Acidithiobacillaceae and Desulfobacteraceae were differentially more abundant in Bodo West spill site than any other site used for comparison. Furthermore, differentially represented species in our study site and other oil-polluted sites ranged from 21 to 42 bacterial families. The findings from this study revealed the bacterial community had a strong dependence on hydrocarbons and that acid-tolerant bacterial families can as well contribute significantly to biodegradation in the site and other polluted sites in Ogoniland usually known to have an acidic pH. Further research on Bodo West spill site will reveal the novel enzymes and pathways for enhanced microbial mediated eco-restoration.

     

Antifungal azoles and azole resistance in the environment: current status and future perspectives—a review

Reviews in Environmental Science and Bio/Technology - Following their extensive use, azole antifungals may enter the environment through the discharge of domestic, industrial and hospital...     

Diversity and functional profile of bacterial communities at Lancaster acid mine drainage dam,South Africa as revealed by 16S rRNA gene high-throughput sequencing analysis

Extremophiles - This study surveyed physicochemical properties and bacterial community structure of water and sediments from an acid mine drainage (AMD) dam in South Africa. High-throughput...