PRODUCTION OF L-DOPA(3,4-DIHYDROXYPHENYL-L-ALANINE) FROM BENZENE BY USING A HYBRID PATHWAY

As an alternative approach to the production of L-DOPA from a cheap ra w material, we constructed a hybrid pathway consisting of toluene diox ygenase, toluene cis-glycol dehydrogenase, and tyrosine phenol-lyase. In this pathway, catechol is formed from benzene through the sequentia l action of toluene dioxygenase and toluene cis-glycol dehydrogenase, and L-DOPA is synthesized from the resulting catechol in the presence of pyruvate and ammonia by tyrosine phenol-lyase cloned from Citrobact er freundii. When the hybrid pathway was expressed in E. coil, product ion of L-DOPA was as low as 3 mM in 4 h due to the toxic effect of ben zene on the cells. In order to reduce lysis of cells, Pseudomonas aeru ginosa was employed as an alternative, which resulted in accumulation of about 14 mM L-DOPA in 9 h, showing a stronger resistance to benzene . (C) 1998 John Wiley & Sons, Inc.