Enzymatic Bioremediation: From Enzyme Discovery to Applications

Abstract

1. Enzymatic bioremediation is potentially a rapid method of removing environmental pesticide residues. Applications include the treatment of residues resulting from agricultural production and processing industries, such as the treatment of irrigation waters, surface-contaminated fruit and vegetables and spent dip liquors. 2. A specific application for some organophosphate-degrading enzymes involves detoxification of nerve agent stockpiles. Effective and affordable remediation requires highly specialized enzymes, so protein engineering techniques are being used to improve properties of various source enzymes to enhance catalytic rates, stability and substrate range. 3. Trials with an optimized organophosphate-degrading enzyme have shown the feasibility of such technology in various applications. 4. The enzymes developed for environmental remediation for specific pesticide classes also have applications as antidotes for high-dose pesticide poisonings and as prophylaxis for people at risk of high pesticide doses.

Fungal Biodegradation of Organophosphorus Insecticides and their Impact on Soil Microbial Population

“…Nonetheless, microbial degradation is considered the major determining factor of the organophosphrus fate in the environment and is often the main process of pesticide degradation in soils, representing the safest, least disruptive and most cost-effective treatment method [30,31]. The results of the present study revealed that fungal degradion of profenofos, diazinon and malathion increased with increasing incubation peroid but at the same time decreased with increasing initial concentrations of insecticides (Tables 5 and 6).…”

“…The effects of different temperatures (20,25,30,35 and 40°C) on diazinon, profenofos and malathion biodegradation in the mineral salts medium are presented in Tables 7 and 8 Means followed by the same letters are not significantly different in each insecticide; -ve, growth not detected 18.01 ± 0.65a 0.0 ± 0.0c 0.00 ± 0.0b 0.00 ± 0.0b Means followed by the same letters are not significantly different in each insecticide The results showed that the increase in temperature enhances the degradation rate of diazinon, profenofos and malathion up to 30°C and 35°C with using M. anisopliae and trichoderma respectively. Recently, it has been reported by many researchers that optimization of different environmental factors can play a vital role in accelerating the process of insecticides biodegradation [38,39].…”

Biochemistry of Microbial Degradation of Hexachlorocyclohexane and Prospects for Bioremediation

“…Bioremediation technologies potentially have four types of applications involving the cleanup of contaminated soils, liquid wastes, stockpiles, and commodities (149,171). All four are relevant to HCH, even though it is no longer in widespread use as an insecticide.…”

The enzymatic basis for pesticide bioremediation

“…Two closely related (~90 % sequence identity) bacterial phosphotriesterases have been extensively characterised: OpdA from Agrobacterium radiobacter [56], and OPH from Pseudomonas diminuta [57] and Flavobacterium [58]. Field trials of OpdA as a bioremediation agent have been conducted [4], and it is already in use as a commercial product to detoxify OP residues in various contaminated wastes, sold under the brand name LandGuard TM from Orica Watercare (Australia) at a cost to user considerably lower than the pesticides themselves.…”

“…The subject of pesticide bioremediation has been considered in several excellent recent reviews covering bioaugmentation, biostimulation [2,3] and enzymatic bioremediation [3,4].…”