Characterization of hydrocarbon degrading microorganisms from Glycine max and Zea mays phytoremediated crude oil contaminated soil.

Microbe-plant partnership in phytoremediation involves a synergistic interaction that leads to degradation of contaminants. The identification and characterization of these microorganisms is fundamental in environmental management. This study is aimed at investigating the influence of Glycine max and Zea mays on microbial make-up and differentiation of soil bacterial and fungal isolates in crude oil contaminated soil. We employed conventional technique of microbial isolation and gene sequencing to evaluate the microbial composition in crude oil contaminated soil. The microorganisms were isolated from crude oil contaminated soil (0%, 4%, 8%) and were identified using 16S rRNA gene (for bacteria) and Internal Transcribed Spacer (ITS) gene (for fungi). We observed a change in the microbial cell density with respect to treatment conditions implying a shift in microbial dynamics to total hydrocarbon utilizing bacteria as the dominant microbes. The sequence data revealed five bacteria strain; Klebsiella aerogenes strain 77, Klebsiella aerogenes strain UISO178, Salmonella enterica strain ABUH7, Klebsiella aerogenes strain M242 and Enterobacter sp. NCCP-607 and three fungi strains; Galactomyces geotrichum strain CBS, Aspergillus niger strain YMCHA73 and Trichoderma virens isolate A701. Annotation analysis using FGENESB and gene scan revealed proteins involved in various metabolic processes and hydrocarbon utilization. GHOSTKOLA output revealed several genetic elements and pathways such as DnaA, PYG, mrcA, environmental, cellular and genetic information processing and degradation enhancers. Our findings show that G. max and Z. mays in association with bacteria can enhance ecosystem restoration of crude oil contaminated soil.

Electrochemical reduction of Cr(VI) in water: lessons learned from fundamental studies and applications.

Converting toxic Cr(vi) to benign Cr(iii) would offer a solution to decontaminate drinking water. Electrochemical methods are ideally suited to carry out this reduction without added external reductants. Achieving this transformation at low overpotentials requires mediating the transfer of protons and electrons to Cr(vi). In this review thermodynamic parameters will be discussed to understand Cr(vi) speciation in water and identify reduction pathways. The electrochemical reduction of Cr(vi) at bare electrodes is reviewed and mechanistic considerations are discussed. Works on modified electrodes are compared to identify key parameters influencing the reduction. An overview of current applications to Cr(vi) reduction is briefly discussed to link fundamental studies to applications.