Microorganisms in soils and waters convert many synthetic organic chemicals to inorganic products. Other compounds are transformed only by cometabolism. These microbial processes may lead to environmental detoxication, the formation of new toxicants, or the biosynthesis of persistent products. Type reactions are proposed for major categories of enzymatic transformation of synthetic chemicals in soils, natural waters, and sewage. Some organic molecules are resistant to microbial attack, and explanations for the persistence of such compounds are suggested.

https://science.sciencemag.org/content/sci/211/4478/132.full.pdf

Biodegradation of Chemicals of Environmental Concern

[4] Trypsinogens and trypsins of various species

Considerable progress has been made in the last few years in understanding the mechanisms of microbial degradation of halogenated aromatic compounds. Much is already known about the degradation mechanisms under aerobic conditions, and metabolism under anaerobiosis has lately received increasing attention. The removal of the halogen substituent is a key step in degradation of halogenated aromatics. This may occur as an initial step via reductive, hydrolytic or oxygenolytic mechanisms, or after cleavage of the aromatic ring at a later stage of metabolism. In addition to degradation, several biotransformation reactions, such as methylation and polymerization, may take place and produce more toxic or recalcitrant metabolites. Studies with pure bacterial and fungal cultures have given detailed information on the biodegradation pathways of several halogenated aromatic compounds. Several of the key enzymes have been purified or studied in cell extracts, and there is an increasing understanding of the organization and regulation of the genes involved in haloaromatic degradation. This review will focus on the biodegradation and biotransformation pathways that have been established for halogenated phenols, phenoxyalkanoic acids, benzoic acids, benzenes, anilines and structurally related halogenated aromatic pesticides. There is a growing interest in developing microbiological methods for clean-up of soil and water contaminated with halogenated aromatic compounds.

Microbial breakdown of halogenated aromatic pesticides and related compounds

(1980). Chlorinated Phenols: Occurrence, Toxicity, Metabolism, And Environmental Impact. CRC Critical Reviews in Toxicology: Vol. 7, No. 1, pp. 1-35.

Chlorinated Phenols: Occurrence, Toxicity, Metabolism, And Environmental Impact

Chemical/biochemical detection of spoilage

A “MUSTY” taint in chicken eggs has been attributed to the presence of 2,3,4,6-tetrachloroanisole (I) in litter shavings by Engel, de Groot and Weurman1, who showed that the feeding of small amounts of this compound to chickens caused a musty taint in both eggs and broiler meat. The samples of shavings that contained 2,3,4,6-tetrachloroanisole (I) also contained pentachloroanisole (II). Following recent occurrences of musty taint in the UK broiler industry, we have examined chicken carcasses and broiler house litter for the presence of chloroanisoles and investigated their origin.

2,3,4,6-tetrachloroanisole association with musty taint in chickens and microbiological formation

The cause and origin of musty taint in chicken from broiler systems has been established as 2,3,4,6-tetrachloroanisole formed by microbial methylation of 2,3,4,6-tetrachlorophenol present as a wood preservative on shavings used as litter. At least three of the fungi found in poultry litter (Scopulariopsis brevicaulis, Aspergillus sydowi and Penicillium crustosum) can effect this methylation. 2,3,4,6-Tetrachloroanisole formed in the litter was taken up by the chickens. The levels in various chicken tissues and factors affecting uptake and loss have been investigated.

Chloroanisoles as a cause of musty taint in chickens and their microbiological formation from chlorophenols in broiler house litters.

http://www.jbc.org/content/243/5/1022.full.pdf

Non-heme Iron Proteins V. THE AMINO ACID SEQUENCE OF RUBREDOXIN FROM PEPTOSTREPTOCOCCUS ELSDENII

Summary: Isolates of 26 fungal species from broiler house litter were screened for their ability to metabolize and methylate 2,3,4,6-tetrachlorophenol over a five-day period, by adding the chlorophenol to cultures after mycelial pellets were established on a complete growth medium. Under these conditions, 99 of the 116 isolates tested metabolized the chlorophenol and 68 of these produced 2,3,4,6-tetrachloro-anisole. The proportion of the chlorophenol methylated to the chloroanisole differed widely with the isolate, even within species. The highest methylation was observed with Penicillium corylophilum; certain other isolates, notably of P. brevicompactum, metabolized almost all the chlorophenol without forming the chloroanisole. Progress studies with these species suggested that there is more than one route for the metabolism of 2,3,4,6-tetrachlorophenol. In tests with suspensions of mixed bacterial populations from broiler house litter, the chlorophenol was metabolized but no methylation was detected.

/pdf/metabolism-of-2-3-4-6-tetrachlorophenol-by-micro-organisms-4se9ah2ld2.pdf

John L. Peel

Papers

2,3,4,6-tetrachloroanisole association with musty taint in chickens and microbiological formation

Chloroanisoles as a cause of musty taint in chickens and their microbiological formation from chlorophenols in broiler house litters.

Non-heme Iron Proteins V. THE AMINO ACID SEQUENCE OF RUBREDOXIN FROM PEPTOSTREPTOCOCCUS ELSDENII

Metabolism of 2,3,4,6-tetrachlorophenol by micro-organisms from broiler house litter.