Pathways for the Degradation of Styrene

Abstract

The monomer styrene can be degraded by various microorganisms under aerobic and anaerobic conditions. Therefore, several peripheral pathways are employed yielding few central intermediates as 3-vinylcatechol, phenylacetic acid, benzoic acid, or 2-ethylhexanol. However, the anaerobic breakdown of styrene is less extensively described compared to the aerobic metabolization, and for the latter mainly Pseudomonads and Actinobacteria have been studied. There is only one styrene-specific pathway, designated side-chain oxidation, reported so far, while all other routes can be considered as unspecific. Thus microorganisms possessing pathways for toluene and biphenyl via direct ring cleavage, for example, can breakdown styrene as well. Besides these degradation capabilities, the partial metabolic activity of higher organisms is mentioned which often yields marker compounds, mandelic acid and phenylglyoxylic acid.