Microbial biodegradation

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

The microbial degradation of azimsulfuron and its effect on the soil bacterial community

Abstract: Aims: Azimsulfuron is a recently introduced sulfonylurea herbicide useful in controlling weeds in paddy fields. To date very little information is available on the biodegradation of this pesticide and on its effect on the soil microbial community. The aim of this work was to study its biodegradation both in slurry soil microcosms and in batch tests with mixed and pure cultures. Methods and Results: Azimsulfuron was applied to forest bulk soil in order to study its effect on the structure of the bacterial soil community, as detectable by denaturant gradient gel electrophoresis (DGGE) analyses. Biodegradation and abiotic processes were investigated by HPLC analyses. In addition, a microbial consortium was selected, that was able to use azimsulfuron as the sole energy and carbon source. One of the metabolites produced by the consortium was isolated and identified through LC-MS analyses. Cultivable bacteria of the consortium were isolated and identified by 16S rDNA sequencing (1400 bp). Conclusions: Azimsulfuron treatment seems to have the ability to cause changes in the bacterial community structure that are detectable by DGGE analyses. It is easily biodegraded both in microcosms and in batch tests, with the formation of an intermediate that was identified as 2-methyl-4-(2-methyl-2H-tetrazol-5-yl)-2H-pyrazole-3-sulfonamide. Significance and Impact of the Study: The study increases the knowledge on the biodegradation of azimsulfuron and its effects on the soil microbiota.

Surfactants and Bacterial Bioremediation of Polycyclic Aromatic Hydrocarbon Contaminated Soil—Unlocking the Targets

Abstract: The activities of man produce significant levels of toxic polycyclic aromatic hydrocarbon compounds (PAHs), which have been identified as excellent candidates for biodegradative removal from contaminated sites. PAHs strongly sorb to soil particles and can also partition into a nonaqueous phase, often limiting bioavailability. In this context, synthetic surfactants and biosurfactants will be discussed as a means to mobilize and solubilize PAHs, potentially increasing bioavailability and subsequent microbial degradation. The fundamentals of bioremediation will be discussed as an important tool that can be used to reduce, remove, or attenuate pollutants at PAH-contaminated sites.

Biodegradation of phenanthrene by fungi screened from nature.

Abstract: Microbial degradation of Phenanthrene with several fungi screened from nature was conducted to select fungi for the bioremediation ofPhenanthrene. Thrichoderma sp. S019, a fungus collected from soil, had the highest rate of degradation on the agar medium containing Phenanthrene. Maximal degradation (72%) was obtained when Trichoderma sp. S019 was incubated for 30 days after the addition of 0.1 mM of Phenanthrene to the liquid medium. Furthermore, the degradation of Phenanthrene was affected by the addition of a carbon source, the addition of a nitrogen source and agitation. Also, 1,2-Dioxygenase and 2,3-Dioxygenase were produced by Trichoderma sp. S019 in a liquid medium. These enzymes play an important role in the metabolism of substrates, revealing a high stereoselectivity for initial dioxygenase and enzymatic hydration since the K-region of phenanthrene was the major site of metabolism. Phenanthrene was indeed degraded by Trichoderma sp. S019 because 1-Hydroxy-2-naphthoic acid, Salicyaldehyde, Salicylic acid and Catechol, considered to be the intermediates in the bioremediation of Phenanthrene, were detected among the reaction products.

Biodegradation of decabromodiphenyl ether (BDE 209) by a newly isolated bacterium from an e-waste recycling area

Abstract: Polybrominated diphenyl ethers (PBDEs) have become widespread environmental pollutants all over the world. A newly isolated bacterium from an e-waste recycling area, Stenotrophomonas sp. strain WZN-1, can degrade decabromodiphenyl ether (BDE 209) effectively under aerobic conditions. Orthogonal test results showed that the optimum conditions for BDE 209 biodegradation were pH 5, 25 °C, 0.5% salinity, 150 mL minimal salt medium volume. Under the optimized condition, strain WZN-1 could degrade 55.15% of 65 μg/L BDE 209 under aerobic condition within 30 day incubation. Moreover, BDE 209 degradation kinetics was fitted to a first-order kinetics model. The biodegradation mechanism of BDE 209 by strain WZN-1 were supposed to be three possible metabolic pathways: debromination, hydroxylation, and ring opening processes. Four BDE 209 degradation genes, including one hydrolase, one dioxygenase and two dehalogenases, were identified based on the complete genome sequencing of strain WZN-1. The real-time qPCR demonstrated that the expression level of four identified genes were significantly induced by BDE 209, and they played an important role in the degradation process. This study is the first to demonstrate that the newly isolated Stenotrophomonas strain has an efficient BDE 209 degradation ability and would provide new insights for the microbial degradation of PBDEs.