Microbial biodegradation

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

Microbial degradation of ethylenediaminetetraacetate in soils and sediments.

Abstract: [14C]ethylenediaminetetraacetate (EDTA) was shown to be slowly biodegraded to 14CO2 in soils and sediments under aerobic conditions and by microorganisms in mixed liquid culture. EDTA chelates of Cu, Cd, Zn, Mn, Ca, and Fe added to soil were equally degraded, while Ni-EDTA was degraded more slowly.

Microbial degradation of the herbicide atrazine and its 2-hydroxy analog in submerged soils

Abstract: the site of application to waters Soil-applied pesticides transported by erosion from and sediments are subject to conditions sufficiently different from those of aerated soils to alter pesticide persistence. Microbial degradation of '4C ring-labeled 2-choro--ethylamino-6-isopropylamino-s-triazine (atrazine) and Its 2-hydroxy analog (hydroxyatrazine) in submerged soils was studied by measurement of 'tCO. evolution and chromatographic se aration of metabolites in soil extracts. In 90 days, 1.67% of hydroxyatrazineC was evolved as ICO2, whereas only 0.005% of atrazine1C was recovered as 'ICO,.. With an energy source added to the soil, 3.8% of hydroxyatrazineIYC was recovered as JV CO, in 60 days. Chemi­ cal hydrolysis of atrazine to hydroxyatrazine is the principal pathway of detoxi­ cation in soil and is conducive to ring cleavage and total breakdown by microbes. Biological dealkylation without dehalogination occurs simultaneously; 2-chlor-4­ amino-6-isopropylamino-s-traizine was identified by TLC in the extracts from atrazine­ treated soil. Ring-labeled atrazine or hydroxyatrazine in soil did not evolve 4 COi. or 'YCHq4gas when the system was subjected to an anaerobic condition. Total breakdown of atrazine is expected to be slower in submerged sediments than In aerated soils because of the higher pH and restricted aeration of sediments.

Microbial Degradation of Alkanes

Abstract: Petroleum hydrocarbons are introduced into the environment through excessive use of fuels and accidental spills during transportation and storage. Alkanes, a major fraction of crude oil, are saturated hydrocarbons and hence are chemically inert as non-polar molecules. However, a number of bacterial and fungal genera have been reported to degrade even high molecular weight alkanes in both aerobic and anaerobic conditions. The degradation process mainly involved enzymes such as methane monooxygenase (MMO), alkane hydroxylase and cytochrome P450 monooxygenase. Besides, a number of environmental factors affect the degradation of alkanes in soils.

Bioremediation of a crude oil - polluted soil by application of fertilizers

Abstract: pollution is a worldwide threat to the environment and the remediation of oil-contaminated soils, sediments and water is a major challenge for environmental research. Bioremediation is a useful method for soil remediation, if pollutant concentrations are moderate and non-biological techniques are not economical. The bioremediation consists strategy of actively aerating the soils and adding fertilizer in order to promote oil biodegradation by indigenous microorganisms. The objective of this study was to investigate whether agricultural fertilizers (N, P, K) enhance the microbial degradation of petroleum hydrocarbons in soil. Artificially polluted soil with %1density of crude oil was used and then fertilizers were applied in 3 levels of 0, 1 and 2 ton/ha in 3 replicates. The soils were kept in 30 oC and 60 percent of field capacity condition for 5 to 10 weeks. To provide the necessary aeration, the soils were tilled twice a week by shovel. Soil sample were analyzed for hydrocarbon-degrading heterophic bacteria count and some soil chemical properties. Residual oil was measured by oil soxhlet extraction method, and gas chromatography. The results showed that the hydrocarbon-degrading and heterotrophic bacteria count in all the treatments increased with time and heterotrophic bacteria population increased from 6×10 3 cfu/g soil to 1.4×10 8 cfu/g soil. Also, soil C/N ratio decreased from 6 to 3. The results indicated that the applied fertilizer increased the degradation of the hydrocarbons compared with the control. Gas chromatography results showed that normal paraffin and isopernoid (Phitane and Pristane) decreased in the range of 45 to 60 percent in all treatments. Furthermore, the results showed that the application of fertilizers at 2 ton/ha rate in oil-contaminated soil lead to greater rates of biodegradation after 5 weeks indicating the feasibility of bioremediation.