Characterization of the biological conversion of naphthalene to (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene in direct micellar systems

The whole cell biological conversion of naphthalene to (+)-cis-(1R,2S)-dihy droxy-1,2-dihydronaphthalene by the E. coli JM109(pPS1778) recombinant stra in carrying the naphthalene dioxygenase and regulatory genes cloned from Ps eudomonas fluorescens N3 in micellar systems has been investigated using bi ochemical and chemico-physical techniques. Reverse and direct micellar syst ems have been tested. Non-ionic surfactants (Tween and Triton X series) wer e found not to inhibit either the growth of the bacteria and the expression of the hydroxylating dioxygenase enzyme in such systems and were utilized in order to speed up the naphthalene conversion by increasing its solubilit y and also its bioavailability. The phase behavior of the direct micellar s ystem was characterized through light scattering and other chemico-physical techniques. Further addition of isopropyl-palmitate 1-2% v/v to the micell ar systems resulted in an increase of the apparent substrate concentration in solution and particularly its bioavailability thus allowing faster catal ytic conversions resulting in an increase in productivity for the process. Since the cis-dihydrodiols are acquiring considerable potential as chiral p ool synthons in asymmetric synthesis for a variety of industrial processes, possible applications for efficient small and large-scale production of su ch compounds are discussed. (C) 1999 Elsevier Science B.V. All rights reser ved.