POSSIBLE REGULATORY ROLE FOR NONAROMATIC CARBON-SOURCES IN STYRENE DEGRADATION BY PSEUDOMONAS-PUTIDA CA-3

Styrene metabolism in styrene-degrading Pseudomonas putida CA-3 cells has been shown to proceed via styrene oxide, phenylacetaldehyde, and p henylacetic acid. The initial step in styrene degradation by strain CA -3 is oxygen-dependent epoxidation of styrene to styrene oxide, which is subsequently isomerized to phenylacetaldehyde. Phenylacetaldehyde i s then oxidized to phenylacetic acid. Styrene, styrene oxide, and phen ylacetaldehyde induce the enzymes involved in the degradation of styre ne to phenylacetic acid by P. putida CA-3. Phenylacetic acid-induced c ells do not oxidize styrene or styrene oxide, Thus, styrene degradatio n by P. putida CA-3 can be subdivided further into an upper pathway wh ich consists of styrene, styrene oxide, and phenylacetaldehyde and a l ower pathway which begins with phenylacetic acid. Studies of the repre ssion of styrene degradation by P. putida CA-3 show that glucose has n o effect on the activity of styrene-degrading enzymes. However, both g lutamate and citrate repress styrene degradation and phenylacetic acid degradation, shelving a common control mechanism on upper pathway and lower pathway intermediates.