Microbial biodegradation

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

Quantifying microbial utilization of petroleum hydrocarbons in salt marsh sediments by using the 13C content of bacterial rRNA.

Abstract: Natural remediation of oil spills is catalyzed by complex microbial consortia. Here we took a wholecommunity approach to investigate bacterial incorporation of petroleum hydrocarbons from a simulated oil spill. We utilized the natural difference in carbon isotopic abundance between a salt marsh ecosystem supported by the 13 C-enriched C4 grass Spartina alterniflora and 13 C-depleted petroleum to monitor changes in the 13 C content of biomass. Magnetic bead capture methods for selective recovery of bacterial RNA were used to monitor the 13 C content of bacterial biomass during a 2-week experiment. The data show that by the end of the experiment, up to 26% of bacterial biomass was derived from consumption of the freshly spilled oil. The results contrast with the inertness of a nearby relict spill, which occurred in 1969 in West Falmouth, MA. Sequences of 16S rRNA genes from our experimental samples also were consistent with previous reports suggesting the importance of Gamma- and Deltaproteobacteria and Firmicutes in the remineralization of hydrocarbons. The magnetic bead capture approach makes it possible to quantify uptake of petroleum hydrocarbons by microbes in situ. Although employed here at the domain level, RNA capture procedures can be highly specific. The same strategy could be used with genus-level specificity, something which is not currently possible using the 13 C content of biomarker lipids. Coastal environments are threatened by petroleum spills ranging from low-level discharges to catastrophic accidents. Large spills commonly are followed by clean-up efforts, but complete containment is rare. In all cases, remediation ultimately depends on microbial degradation. The rate of this natural bioremediation varies with physical and biological factors (temperature, wind and wave action, macroecology, and microbial community diversity), all of which have been extensively studied and reviewed (3, 4, 23, 27, 42, 69).

Dynamics of soil microbial populations involved in 2,4-D biodegradation revealed by FAME-based Stable Isotope Probing.

Abstract: Stable Isotope Probing (SIP) is a powerful tool for analysing the fate of pesticides in soil. Together with FAME (Fatty Acid Methyl Esters), it can help identify biodegradation pathways and recycling into the microbial biomass. The fate of ring-labelled 13C-2,4-dichlorophenoxyacetic acid or 2,4-D (C2,4-D) was determined in soil during a 6-month incubation. The distribution of 13C among the microbial biomass, the CO2 respired, the water, methanol and dichloromethane soluble fractions, and the residual non-extracted bulk soil was measured. Molecular analyses were carried out on the lipid and the non-extractable fractions. After 8 days, about half of the initial amount of C2,4-D was mineralised; the other half remained in soil as non-extractable residues (NER). C2,4-D continued to be mineralised, suggesting that NER were still bioavailable. Analysis of C2,4-D-enriched FAME contained in the lipid fraction suggested that a succession of microbial populations was involved in 2,4-D biodegradation. This is possibly due to the change of 2,4-D availability. The C2,4-D yield coefficient and degrader diversity evolved during the incubation, providing corroboratory evidence that different physiological groups were active during the incubation. The 13C-labelled microbial community was always less diverse than the total community, even at the end of the incubation, suggesting that the cross-feeding community is also a specific part of the total community. This work shows that molecular analysis of 13C-labelled pesticides is a useful tool for understanding both chemical and biological aspects of their fate in soil.

Microbial Degradation of Indole and Its Derivatives

Abstract: Indole and its derivatives, including 3-methylindole and 4-chloroindole, are environmental pollutants that are present worldwide. Microbial degradation of indole and its derivatives can occur in several aerobic and anaerobic pathways; these pathways involve different known and characterized genes. In this minireview, we summarize and explain the microbial degradation of indole, indole-3-acetic acid, 4-chloroindole, and methylindole.

Microbial degradation of xenobiotic, aromatic pollutants in humic water.

Abstract: The microbial degradation of a number of 14C-labeled, recalcitrant, aromatic pollutants, including trichloroguaiacol and di-, tri-, and pentachlorophenol, was investigated in aquatic model systems in the laboratory. Natural, mixed cultures of microorganisms in the water from a brown-water lake with a high content of humic compounds mineralized all of the tested substances to a higher degree than did microorganisms in the water from a clear-water lake. Dichlorophenol was the most rapidly degraded pollutant.