BACTERIA AND THE BIODEGRADATION OF CHEMICALS ACHIEVED NATURALLY, BY COMBINATION, OR BY CONSTRUCTION

The natural potential of bacteria for the biological degradation of sy nthetic compounds is greater than is commonly supposed and extends to many heteroarenes and even some chloroarenes. An increase in the numbe r of substituents on the aromatic ring or a certain substitution patte rn is what confers xenobiotic character to a compound. In addition, wh en enzymes with low substrate specificity encounter foreign compounds with random variations, products with very strong xenobiotic character often result. In this case, changing the conditions or introducing a cooperation between several different types of bacteria can be used to degrade these compounds. Finally, mineralization, the complete breakd own of organic substances into carbon dioxide and inorganic salts, of xenobiotics previously regarded as persistent can be achieved by takin g advantage of natural or induced gene transfer to construct hybrid de gradative pathways. After an introduction to the world of bacteria and their place in nature, we will describe their natural potential for b iodegradation with reference to aliphatic and aromatic hydrocarbons. T he discussion will then turn to the types of the substituents that con fer xenobiotic properties to compounds and how these compounds are deg raded despite their xenobiotic character.