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 chloroform

Abstract: Chloroform (CF) is largely produced by both anthropogenic and natural sources. It is detected in ground and surface water sources and it represents the most abundant halocarbon in the atmosphere. Microbial CF degradation occurs under both aerobic and anaerobic conditions. Apart from a few reports describing the utilization of CF as a terminal electron acceptor during growth, CF degradation was mainly reported as a cometabolic process. CF aerobic cometabolism is supported by growth on short-chain alkanes (i.e., methane, propane, butane, and hexane), aromatic hydrocarbons (i.e., toluene and phenol), and ammonia via the activity of monooxygenases (MOs) operatively divided into different families. The main factors affecting CF cometabolism are (1) the inhibition of CF degradation exerted by the growth substrate, (2) the need for reductant supply to maintain MO activity, and (3) the toxicity of CF degradation products. Under anaerobic conditions, CF degradation was mainly associated to the activity of methanogens, although some examples of CF-degrading sulfate-reducing, fermenting, and acetogenic bacteria are reported in the literature. Higher CF toxicity levels and lower degradation rates were shown by anaerobic systems in comparison to the aerobic ones. Applied physiological and genetic aspects of microbial cometabolism of CF will be presented along with bioremediation perspectives.

Comparative degradation of organophosphorus insecticides in soil: specificity of enhanced microbial degradation

Abstract: Laboratory experiments investigated the comparative degradation of six organophosphorus insecticides in soil as affected by enhanced microbial degradation. The degradation rates and product distributions of chlorpyrifos, fonofos, ethoprop, terbufos, and phorate were not dramatically altered in soils containing microbial populations adapted to rapidly degrade isofenphos. An Arthrobacter sp. isolated from soils with a history of isofenphos use rapidly metabolized isofenphos in pure culture but did not metabolize or cometabolize any of the other five organophosphorus insecticides. Likewise, only fonofos was rapidly degraded in soil with a long history of fonofos use. None of the organophosphorus insecticides were rapidly degraded in soil containing carbofuran-degrading microbial populations. Results indicate that the phenomenon of enhanced microbial degradation of soil insecticides may exhibit some degree of specificity.

Microbial degradation of nitroaromatic compounds.

Abstract: Publisher Summary This chapter presents an overview of microbial degradation of nitroaromatic compounds. Nitroaromatics are produced on a massive scale in the manufacture of dyes, plastics, and explosives. Their discharge in wastewater and application as pesticides have broadened their environmental impact and called for solutions for remediation of these toxic compounds. The use of microorganisms to transform or eliminate nitroaromatics has been proposed in effluent treatment and land reclamation. While microbial strains utilizing nitrobenzoates or nitrophenols were isolated from contaminated sources several decades ago, microbial action on 2,4,6-trinitrotoluene (TNT) was largely limited to nitro group reduction and formation of azoxy derivatives which may complex with humus. However, recent work has identified organisms capable of using TNT as the sole carbon and nitrogen source. Finally, the versatile white rot fungus also merits further attention in nitroaromatic degradation.