Toxins microbial degradation

The toxin may undergo microbial degradation either while it is free in soil solution or while it is adsorbed. This could destroy all or part of the toxin, and there is evidence that most of the natural organic chemical groups that contain allelopathic compounds can be metabolized by some microorganism. The possibility always exists, however, that the microbial degradation product from the metabolism of an active toxin will itself be an allelopathic chemical. 

There has been considerable interest in the use of plants for bioremediation and this merits a rather extensive discussion. Plants can play an important role in bioremediation for several reasons (1) they can transport contaminants from the soil, (2) they can metabolize the contaminants after uptake, or (3) they can produce exudes that support microbial activity for degradation of the contaminants. In addition, bacteria can produce metabolites that counter the effect of toxins produced by fungi, and serve as biocontrol agents that diminish the need for the application of agrochemicals. Plant exudates play an important role in supporting the growth and activity of bacteria that carry out the degradation of contaminants in the rhizosphere and rhizoplane (the external surface of roots... 

Procedures aimed at reducing or detoxifying aflatoxins and/or their effects have been reviewed by Phillips et al. (35), and include technological procedures for food and feeds and chemical degradation, as well as biocontrol and microbial inactivation, dietary modification and chemoprotection, and reduction in toxin bioavailability via selective chemisorption with clay. 

Cytochrome P-450s are the best-known class of hydroxylation enzyme. Their active sites contain a heme iron that forms a highly activated oxygenating species that reacts by a radical mechanism. In higher animals, they function primarily in metabolite degradation as part of pathways that clear unnatural substances such as toxins and drugs. Hydroxylation inaeases polarity that facilitates further derivatization by other detoxification enzymes or excretion of the hydroxylated products. Other P-450 family members are involved in secondary metabolite biosynthesis, particularly in plants and microbial cells (Figure 1.6). 

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