Co-metabolic formation of substituted phenylacetic acids by styrene-degrading bacteria.

Some soil bacteria are able to metabolize styrene via initial side-chain oxygenation. This catabolic route is of potential biotechnological relevance due to the occurrence of phenylacetic acid as a central metabolite. The styrene-degrading strains 1CP, ST, and the novel isolates sp. Kp5.2 and sp. CWB2 were investigated with respect to their applicability to co-metabolically produce substituted phenylacetic acids. Isolates were found to differ significantly in substrate tolerance and biotransformation yields. Especially, ST was identified as a promising candidate for the production of several phenylacetic acids. The biotransformation of 4-chlorostyrene with cells of strain ST was shown to be stable over a period of more than 200 days and yielded about 38 mmol g after nearly 350 days. Moreover, 4-chloro-α-methylstyrene was predominantly converted to the ()-enantiomer of the acid with 40% enantiomeric excess.