Development of a bioconversion process for production of cis-1S,2R-indandiol from indene by recombinant Escherichia coli constructs

Recombinant Escherichia coli cells expressing the toluene dioxygenase (TDO) genes from Pseudomonas putida convert indene to cis-1S,2R-indandiol, a pot entially important intermediate for the chemical synthesis of the HIV-1 pro tease inhibitor, Crixivan. A bioconversion process was developed through op timization of medium composition and reaction conditions at the shake-flask and 23-l fermenter scales. A cis-1,2-indandiol productivity of approx. 100 0 mg/l was achieved with construct TDO123, which represents a 50-fold incre ase over the initial titer. Varying the bioconversion conditions did not ch ange the enantiomeric excess (e.e.) for the 1S,2R enantiomer from about 30% , suggesting that toluene dioxygenase intrinsically converts indene to 1S,2 R- and 1R,2S-indandiols at a ratio of 2:1. Further inclusion of the Pseudom onas dehydrogenase gene in construct D160-1 led to the production of chiral ly pure cis-1S,2R-indandiol (e.e. > 99%)as a result of the selective degrad ation of the 1R,2S enantiomer, with the overall yield (650 mg/l) proportion ally reduced. A single stage process was developed for D160-1 and scaled up to the 23-1 fermenter, achieving a cis-1S,2R-indandiol titer of 1200 mg/l.