Microbial biodegradation

About: Microbial biodegradation is a research topic. Over the lifetime, 1647 publications have been published within this topic receiving 75473 citations.

Advances in microbial biodegradation of chlorpyrifos

Abstract: Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate) an organophosphate pesticide is one of the most commonly used insecticide, acaricide and termiticide in agriculture, households and public health. The exposure of this moderately hazardous pesticide creates health concerns due to choline esterase inhibition, neurotoxicity, psychological and immunological effects. The microbial bioremediation of chlorpyrifos is a viable option for cleaning up the contaminated sites with its eco-friendliness, high efficiency and costeffectiveness. Several researchers reported potential bacterial strains like Pseudomonas sp., Arthrobacter sp., Bacillus sp., Klebsiella sp., Serratia marcescens, Enterobacter sp., Stenotrophomonas sp., Sphingomonas sp., Flavobacterium sp. etc., fungal strains such as Phanerochaete chrysosporium, Aspergillus terreus, Verticillium sp., Trichoderma harzianum, etc. and cyanobacteria like Anabaena sp., Aulosira fertilissima, Phormidium valderianum for chlorpyrifos degradation. The microbes capable of producing biosurfactants increase biodegradation efficiency of chlorpyrifos by improving bioavailability of the xenobiotic compound by developing critical micellar concentration. The complete detoxification of the pesticide occurs with those microbes that also degrade its metabolites and avoid its accumulation in the environment. The cloning of mpd gene from chlorpyrifos degrading bacterial strains to Escherichia coli helps in developing its biodegradation capability. This paper focuses on the advancements in chlorpyrifos biodegradation for the efficient onsite remediation of the contaminated environment.

Biochemical properties and biodegradation of dissolved organic matter from soils

Abstract: Various biologically mediated processes are involved in the turnover of dissolved organic matter (DOM) in soil; however, relatively little is known about the dynamics of either the microbial community or the individual classes of organic molecules during the decomposition of DOM. We examined the net loss of DOC, the mineralisation of C to CO2 and the degradation of DOC from six different soils by soil microorganisms. We also quantified the changes in the concentrations of protein, carbohydrate and amino acid C during microbial biodegradation. Over a 70-day incubation period at 20°C, the mineralisation of DOC to CO2 was described by a double exponential model with a labile pool (half-life, 3–8 days) and a stable pool (half-life, 0.4–6 years). However, in nearly all cases, the mass loss of DOC exceeded the C released as CO2 with significant deviations from the double exponential model. Comparison of mass DOC loss, CO2 production and microbial cell counts, determined by epifluorescence microscopy, showed that a proportion of the lost DOC mass could be accounted for by microbial assimilation. Carbohydrate and protein C concentrations fluctuated throughout the incubation with a net change of between 3 to 13 and −30 to 22.4% initial DOC, respectively. No amino acid C was detected during the incubation period (level of detection, 0.01 mg C l−1).

Correlation of Microbial Degradation Rates with the Chemical Structure

Abstract: Structure/reactivity relations are investigated experimentally and theoretically for the microbial degradation of 35 substituted phenols and anilines by adapted mixed cultures of bacteria. From the results one can conclude that the initial attack of the aromatic nucleus has an electrophilic character and is ratelimiting. The results are suitable for predictions of biodegradation rates of organic compounds and facilitate understanding of the mechanism of degradation.

Microbial degradation and treatment of polycyclic aromatic hydrocarbons and plasticizers

Abstract: Rhodococcus erytropolis and Pseudomonas sp. rapidly degrade many kinds of polycyclic aromatic hydrocarbon (PAH) compounds such as phenanthrene and phthalate esters such as di(2-ethylhexyl) phthalate, used as plasticizers. These compounds were efficiently removed from wastewater by inoculating viable cells of Rhodococcus erythropolis and Pseudomonas sp. into activated sludge as a biological treatment system. The rapid PCR method and fluorescent antibody techniques were successfully applied for tracing the specified microorganisms, which were inoculated into a mixed culture system. The relationship of microflora to the removal rate of these compounds such as phthalate esters in inoculated biological treatment systems was examined. The metabolic pathway was investigated and enzymes were purified.