Screening and evaluation of some green algal strains (Chlorophyceae) isolated from freshwater and soda lakes for biofuel production

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Evolution and Emergence of Antibiotic Resistance in Given Ecosystems: Possible Strategies for Addressing the Challenge of Antibiotic Resistance

Antibiotics were once considered the magic bullet for all human infections. However, their success was short-lived, and today, microorganisms have become resistant to almost all known antimicrobials. The most recent decade of the 20th and the beginning of the 21st century have witnessed the emergence and spread of antibiotic resistance (ABR) in different pathogenic microorganisms worldwide. Therefore, this narrative review examined the history of antibiotics and the ecological roles of antibiotics, and their resistance. The evolution of bacterial antibiotic resistance in different environments, including aquatic and terrestrial ecosystems, and modern tools used for the identification were addressed. Finally, the review addressed the ecotoxicological impact of antibiotic-resistant bacteria and public health concerns and concluded with possible strategies for addressing the ABR challenge. The information provided in this review will enhance our understanding of ABR and its implications for human, animal, and environmental health. Understanding the environmental dimension will also strengthen the need to prevent pollution as the factors influencing ABR in this setting are more than just antibiotics but involve others like heavy metals and biocides, usually not considered when studying ABR

Targeted 16S rRNA amplicon analysis reveals the diversity of bacterial communities in carwash effluents

Follow the DOI link at the top of the record to access the full-text on the publisher's websiteThis study aimed to analyze the bacterial diversity in carwash effluents and to determine their potential for use in microbial degradation of environmental contaminants. Nine carwash effluent samples were collected for physicochemical and bacterial community diversity analysis using multi-digital probes and 16S rRNA gene amplicon sequencing respectively. The pH of all effluent samples was neutral to slightly alkaline. Oil and grease concentrations ranged from 15.3 to 49.7 mg/L. 16S gene amplicon sequencing of the nine samples produced 45,934-sequence reads, which translated to 13 bacterial phyla, 26 classes, and 43 genera. The most dominant phyla were Proteobacteria, Bacteroidetes, Firmicutes, and Fusobacteria. Canonical correspondence analysis (CCA) showed that the distribution of the phyla Proteobacteria, Bacteroidetes, Acidobacteria, and Verrucomicrobia was influenced by the presence of oil and grease, total petroleum hydrocarbons-gasoline range organics (GRO-TPH), and metals species (Pb, Cu, and Zn). The dominant bacterial genera found in the present study were previously proven to biodegrade hydrocarbons, and their presence in carwash effluents could bode well for in situ natural bioremediation of these contaminated sites.University Of South AfricaEnvironmental Science

Unveiling the Potency and Harnessing the Antibacterial Activities of Plant Oils against Foodborne Pathogens

The rising concerns regarding antibiotic resistance and the harmful effects of synthetic preservatives have led to an increasing interest in exploring natural alternatives. Plant oils have been traditionally used for their antimicrobial properties, but systematic investigations into their efficacy against foodborne pathogens are necessary for potential applications in food preservation. This study aimed to evaluate the antibacterial potential of various plant oils (neem, coconut, castor, and olive oil) against common foodborne pathogens and analyze their chemical composition using gas chromatography–mass spectrometry (GC-MS). The oils were tested against foodborne pathogens using the disk diffusion method. Minimum inhibitory concentrations (MICs) were determined to assess the potency of the oils. GC-MS was employed to identify the compounds present in each oil. Neem oil exhibited significant antibacterial activity against all tested pathogens, with pronounced effects against Staphylococcus aureus and Bacillus cereus. Coconut oil showed notable activity against Listeria monocytogenes. Castor oil displayed moderate activity, while olive oil exhibited minimal antibacterial effects. The GC-MS analysis revealed a diverse array of compounds in neem oil, which is likely to contribute to its potent antibacterial properties. Neem and coconut oils, owing to their rich bioactive components, emerged as promising candidates for the development of natural antimicrobial agents. These brief findings support the potential application of plant oils in food preservation and emphasize the need for further research into understanding the underlying mechanisms and optimizing their use

Assessing the Potential of Some Freshwater and Saline Microalgae as Biodiesel Feedstock

Microalgae have attracted a major interest in biofuel, food and feed stock sectors as they can accumulate lipids, proteins and carbohydrates in large amounts within short periods of time. The selection of the most suitable algal species for biofuel production is based on key parameters such as lipids, fatty acids composition and characteristics. This paper describes the bioprospecting and molecular screening of 21 microalgal strains isolated from different fresh and saline water habitats by analysing their biomass, lipids and fatty acid profiles, used for estimating biodiesel properties. Biomass productivity amongst the strains varied from 142.5±13.4 to 622.8±14.0 mg/L. Seven strains viz. Acutodesmus sp. TST2, Scenedesmus sp. PK1, Desmodesmus armatus TTT1, Desmodesmus armatus FW005, Neochloris sp. RP2, Stichococcus bacillaris LU1 and Hegewaldia sp. LC1 showed a lipid mass fraction of >25% on a dry basis. Fatty acid profiling showed that fatty acids with carbon chain length of C16–C18 such as palmitic, oleic and linoleic acids were major fatty acids in all the isolated species. Three strains viz. Acutodesmus sp. TST2, Stichococcus bacillaris LU1 and Hegewaldia sp. LC1 accumulated high lipid content (>28% dwt), with higher levels of fatty acid profiles of C16–C18 (>70%) indicating their potential as sources of biodiesel with suitable biodiesel properties of high cetane number (57–59), low viscosity (4.73–4.85 mm2/s), lower iodine value (54.4–68.5 gl2/100 g), relative cloud point 9–13 °C) and negative cold filter plugging point (–2 to –6 °C) in accordance with international standards

High-throughput amplicon sequencing datasets of microbial community in soils irrigated by quicklime and fly ash-treated acid mine drainage water

In water-stressed regions, the use of treated acid mine drainage (AMD) water for irrigated agriculture has been suggested as an alternative to address the shortage of fresh water sources. However, the short and long-term impact of using such (un)treated AMD water on soil health, particularly the microbiome structure and functional capacity, is not known. We present high-throughput amplicon sequence (HTS) datasets of purified microbial metacommunity DNA of soils under Irish potato production irrigated by quicklime and fly ash treated AMD water. The irrigation treatments included quicklime treated AMD water (A1Q and A2Q; n = 16), and quicklime and fly ash-treated AMD water (AFQ; n = 5), untreated AMD water (uAMD; n = 7) and control group using tap water (n = 5). The V1-V3 hypervariable region of the 16S rRNA gene from each sample were sequenced on an Illumina MiSeq to generate these HTS datasets. The raw sequences underwent quality-checking, demultiplexing into FASTQ files, and processing using MOTHUR pipeline (v1.40.0). Th quality reads classified into taxonomic ids (phylum, class, order, family, and genus) using the Naïve Bayesian classifier algorithm against the SILVA database (v132) and were assigned to operational taxonomic units (OTUs) based on the pairwise distance matrix (Euclidean distance matrix). The applicability of the HTS datasets was confirmed by microbial taxa at the phylum level. All HTS datasets are available through the BioSample Submission Portal under the BioProject ID PRJNA974836 (https://www.ncbi.nlm.nih.gov/bioproject/974836)

Investigating Industrial Effluent Impact on Municipal Wastewater Treatment Plant in Vaal, South Africa

Industrial effluents with high concentrations of toxic heavy metals are of great concern because of their persistence and non-degradability. However, poor operation and maintenance of wastewater treatment infrastructure is a great concern in South Africa. In this study, physico-chemical parameters and heavy metals (HMs) concentration of wastewater from five different industries, Leeuwkuil wastewater treatment plant (WWTP) inflow and effluent, and Vaal River water samples were monitored between January and September 2017, to investigate the correlation between heavy metal pollution and the location of industries and ascertain the effectiveness of the municipal WWTP. Physico-chemical variables such as pH, biological oxygen demand (BOD), dissolved oxygen (DO), chemical oxygen demand (COD), total dissolved solids (TDS) and electrical conductivity (EC) exhibited both temporal and spatial variations with the values significantly higher in the industrial samples. Inductively coupled plasma optical emission spectrometry (ICP-OES) results also showed that aluminium (Al), copper (Cu), lead (Pb) and zinc (Zn) were significantly higher in industrial effluents (p < 0.05), with only Zn and Al exhibiting significant seasonal variability. Statistical correlation analysis revealed a poor correlation between physicochemical parameters and the HMs compositional quality of wastewater. However, toxic HMs (Zn, Cu and Pb) concentrations in treated wastewater from WWTP were above the permissible limits. Although the WWTP was effective in maintaining most of the wastewater parameters within South African Green drop Standards, the higher Cu, Zn, Pb and COD in its final effluent is a concern in terms of Vaal river health and biological diversity. Therefore, we recommend continuous monitoring and maintenance of the WWTPs infrastructure in the study area

Community diversity metrics, interactions, and metabolic functions of bacteria associated with municipal solid waste landfills at different maturation stages

Abstract Municipal landfills are hot spots of dynamic bioprocesses facilitated by complex interactions of a multifaceted microbiome, whose functioning in municipal landfills at different maturing stages is poorly understood. This study determined bacterial community composition, interaction conetworks, metabolic functions, and controlling physicochemical properties in two landfills aged 14 and 36 years. High throughput sequencing revealed a similar distribution of bacterial diversity, evenness, and richness in the 14‐ and 36‐year‐old landfills in the 0–90 cm depth. At deeper layers (120–150 cm), the 14‐year‐old landfill had significantly greater bacterial diversity and richness indicating that it is a more active microcosm than the 36‐year‐old landfill, where phylum Epsilonbacteraeota was overwhelmingly dominant. The taxonomic and functional diversity in the 14‐year‐old landfill was further reflected by the abundant presence of indicator genera Pseudomonas,Lutispora,Hydrogenspora, and Sulfurimonas coupled with the presence of biomarker enzymes associated with carbon (C), nitrogen (N), and sulfur (S) metabolism. Furthermore, canonical correspondence analysis revealed that bacteria in the 14‐year‐old landfill were positively correlated with high C, N, S, and phosphorus resulting in positive cooccurrence interactions. In the 36‐year‐old landfill, negative coexclusion interactions populated by members of N fixing Rhizobiales were dominant, with metabolic functions and biomarker enzymes predicting significant N fixation that, as indicated by interaction network, potentially inhibited ammonia‐intolerant bacteria. Overall, our findings show that diverse bacterial community in the 14‐year‐old landfill was dominated by copiotrophs associated with positive conetworks, whereas the 36‐year‐old landfill was dominated by lithotrophs linked to coexclusion interactions that greatly reduced bacterial diversity and richness

Microbial Surfactants: The Next Generation Multifunctional Biomolecules for Applications in the Petroleum Industry and Its Associated Environmental Remediation

Surfactants are a broad category of tensio-active biomolecules with multifunctional properties applications in diverse industrial sectors and processes. Surfactants are produced synthetically and biologically. The biologically derived surfactants (biosurfactants) are produced from microorganisms, with Pseudomonas aeruginosa, Bacillus subtilis Candida albicans, and Acinetobacter calcoaceticus as dominant species. Rhamnolipids, sophorolipids, mannosylerithritol lipids, surfactin, and emulsan are well known in terms of their biotechnological applications. Biosurfactants can compete with synthetic surfactants in terms of performance, with established advantages over synthetic ones, including eco-friendliness, biodegradability, low toxicity, and stability over a wide variability of environmental factors. However, at present, synthetic surfactants are a preferred option in different industrial applications because of their availability in commercial quantities, unlike biosurfactants. The usage of synthetic surfactants introduces new species of recalcitrant pollutants into the environment and leads to undesired results when a wrong selection of surfactants is made. Substituting synthetic surfactants with biosurfactants resolves these drawbacks, thus interest has been intensified in biosurfactant applications in a wide range of industries hitherto considered as experimental fields. This review, therefore, intends to offer an overview of diverse applications in which biosurfactants have been found to be useful, with emphases on petroleum biotechnology, environmental remediation, and the agriculture sector. The application of biosurfactants in these settings would lead to industrial growth and environmental sustainability