Pesticides in Foods: Towards Bioremediation Biocatalysts?

Abstract

The presence of hazardous chemical compounds in foods is a growing concern in almost every country. Although some toxins come from microbial contamination, a major part comes from residues of pesticides used for plant health and food preservation. Despite plans to decrease their use, the concentration of hazardous residues encountered in food is growing. The societal solution to this issue is to find alternatives to chemicals and replace the most hazardous by biodegradable, fewer toxic compounds. However, as this greener transition takes some time, any transitory solution to decrease the risks of contamination is welcome. Among them, the stimulation of microbial pesticide degradation in food in a similar way to bioremediation in the environment would be very positive. In this review, we present the problem of food contamination, focusing on organophosphates and organochlorines, and the various possibilities of microbial decontamination. We discuss the possible use of microbial biocatalysts as a biopreservation tool. We conclude that, although this process is very promising, it lacks research taking into account the various degradation products and the elaboration of screening procedures able to choose some rare, efficient biopreservation strains.

The function of microbial enzymes in breaking down soil contaminated with pesticides: a review

“…Bacteria and fungi are the primary organisms engaged in biodegradation [ 5 , 22 , 25 – 27 ]. Bacterial species discovered to be capable of pesticide degradation often belong to the genera Flavobacterium , Burkholderia , Arthrobacter , Azotobacter , and Pseudomonas [ 5 , 12 , 18 , 24 , 28 , 29 ]. Once these biotas are released to the soil, they are capable of quickly developing and they breakdown particular pesticide compounds that serve as carbon and energy source to these soil microorganisms, opening the way for the remediation of pesticide-contaminated sites [ 9 , 15 , 18 , 30 ].…”

“…Reduction reactions may occur even though relatively uncommon [ 9 , 38 ]. Cytochrome P450 (CYP) [ 28 ], flavin-dependent monooxygenases (FMO) [ 18 , 20 ], and hydrolases [ 9 , 11 , 20 , 28 , 29 , 34 ] have all been documented to play key roles in the oxidation and reduction of pesticides. CYP undergoes mono-oxygenation processes that metabolize a variety of pesticides, including aldrin through epoxidation, parathion by oxidative desulfurization, and alachlor and atrazine via N -dealkylation [ 30 , 39 ].…”

“…While AChE is not capable of degrading OP compounds, the enzyme catalysts found in microbial species have been reported to capable of degrading OP compounds [ 11 , 21 , 29 ]. The most extensively researched are the OP hydrolyzing enzymes, which have emerged as an intriguing approach for decontaminating OP substances.…”

“…The most extensively researched are the OP hydrolyzing enzymes, which have emerged as an intriguing approach for decontaminating OP substances. The six primary OP hydrolases are organophosphate hydrolase (OpdA), diisopropylfluorophosphatase (DFPase), phosphotriesterase or OP hydrolases (PTE or OPH), paraoxonase (PON1), organophosphate acid anhydrolase (OPAA), and SsoPox [ 9 , 11 , 28 , 29 ].…”

“…The OpdA enzyme has a barrel structure with a heterobinuclear Fe–Zn metal core, which leads to an increase in specific activity when cobalt is added [ 9 ]. The OpdA enzyme has been shown to hydrolyze a broad range of OP pesticides, including chlorpyrifos, diazinon, dichlorvos, dimethoate, malathion, methyl parathion, and ethyl parathion [ 19 , 29 ]. To illustrate, the hydrolysis of diazinon, an OP insecticide, by the phosphotriesterases OpdA yields diethyl thiophosphoric acid and 2-isopropyl-4 methyl-pyrimidin-6-ol [ 19 ].…”