Conditions Optimizing and Application of Laccase-mediator System (LMS) for the Laccase-catalyzed Pesticide Degradation

Abstract

A high capacity of laccase from Trametes versicolor capable of degrading pesticides has been revealed. The conditions for degrading of five selected pesticides including chlorpyrifos, chlorothalonil, pyrimethanil, atrazine and isoproturon with the purified laccases from Trametes versicolor were optimized. The results showed that the optimum conditions for the highest activity were pH at 5.0 and temperature at 25 °C. The best mediators were violuric acid for pyrimethanil and isoproturon, vanillin for chlorpyrifos, and acetosyringone and HBT for chlorothalonil and atrazine, respectively. The laccase was found to be stable at a pH range from 5.0 to 7.0 and temperature from 25 to 30 °C. It was observed that each pesticide required a different laccase mediator concentration typically between 4.0–6.0 mmol/L. In the experiment, the degradation rates of pyrimethanil and isoproturon were significantly faster than those of chlorpyrifos, chlorothalonil and atrazine. For example, it was observed that pyrimethanil and isoproturon degraded up to nearly 100% after 24 hours while the other three pesticides just reached up 90% of degradation after 8 days of incubation.

Pilot scale production of extracellular thermo‐alkali stable laccase from Pseudomonas sp. S2 using agro waste and its application in organophosphorous pesticides degradation

“…A number of researchers have shown the ability of fungal laccase enzyme using a mediator to degrade pesticide in agricultural soil . Enzymes produced from Trametes versicolor were capable of degrading 5 pesticides including atrazine, pyrimethanil, chlorpyrifos, isoproturon and chlorothalonil at a temperature of 25 °C in the presence of mediator violuric acid, vanillin, acetosyringone and HBT . Trametes versicolor laccase exhibited efficient degradation of nerve agents O‐ethyl S‐[N,N‐diisopropylaminoethyl] methylphospho nothiolate (VX), O‐ethyl‐S‐[2‐(diisopropylamino)ethyl] phenylphosphonothioate (PhX) and RVX using ABTS as mediator .…”

“…36 Enzymes produced from Trametes versicolor were capable of degrading 5 pesticides including atrazine, pyrimethanil, chlorpyrifos, isoproturon and chlorothalonil at a temperature of 25 ∘ C in the presence of mediator violuric acid, vanillin, acetosyringone and HBT. 6 phenylphosphonothioate (PhX) and RVX using ABTS as mediator. 37 In another study, among nine tested mediators, syringaldehyde and acetosyringone play a very important role in the degradation of halogenated pesticide.…”

“…Many approaches have been investigated for their effective reduction such as photooxidation and chemical degradation . More recently, enzymatic catalysis has received increasing attention, with ligninolytic enzymes, especially laccase, being of great interest due to its wide range of substrates …”

“…4 More recently, enzymatic catalysis has received increasing attention, with ligninolytic enzymes, especially laccase, being of great interest due to its wide range of substrates. 5,6 Laccases are ubiquitously found glycoproteins, ranging from various fungi to higher plants. They are mainly produced from fungi especially white rot and have been extensively exploited for application in industrial processes due to their high redox potential.…”

Biodegradation of atrazine and ligninolytic enzyme production by basidiomycete strains 

“…Despite the limitations imposed by the incomplete atrazine biodegradation by basidiomycetes in pure cultures, studies applying puri ed ligninolytic enzymes under controlled conditions, or adopting cocultures involving soil bacteria and deuteromycetes, have been successful in achieving complete dissipation of atrazine and detoxi cation of contaminated substrates [4,18,19]. White-rot fungi bioremediation approaches also present the advantage of being low cost processes, once fungal species are usually not fastidious; being mainly saprophytes, their growth can be easily supported by the organic residues, in laboratory culture conditions or in the eld [20].…”