Enantioselective sulfoxidation using Streptomyces glaucescens GLA.0

Abstract

Application of Streptomyces glaucescens as a whole-cell oxidative biocatalyst without using an external cofactor.

Reviewing a plethora of oxidative-type reactions catalyzed by whole cells ofStreptomycesspecies

“…The latter is a natural product isolated from Juglans mandshurcia Maximowicz, which has anti-leishmanial and antidiabetic activities. 70 Among different cultures, S. griseus NRRL B8090 gave the highest conversion, and the subsequent trials with the whole cells for a preparative scale conversion of 150 mg naphthalene resulted in 81 mg of the pure product aer 72 h. Furthermore, another derivative, 2-methyl-1,4naphthoquinone (31), was converted to the corresponding hydroxyl compounds (32) with the whole cells of the same Streptomyces strain (Scheme 10). 70 Gurram et al (2009) reported the use of S. griseus NCIM 2622, among ve tested actinomycetes, to catalyze the oxidation of meloxicam ( 33), a non-steroidal anti-inammatory drug, into two metabolites: 5-hydroxymethyl meloxicam (34) and trace amounts of 5-carboxy meloxicam (35) (Scheme 11), with a higher biological activity.…”

“…Furthermore, cloning and expression of the enzymes involved the oxidation reactions will be useful for understanding the enzyme features for activity and stability, and for designing better enzymes. Selective heteroatom oxidations have just been reported for some Streptomyces species, 32,88 in addition to specic oxidation of unactivated C-H bonds, 78,80 which opens up the possibilities for further studies on identifying the enzymes involved in such species. Development of expression hosts for the genes from Streptomyces species is yet another aspect that would be needed for increasing the utilization of these important biocatalysts.…”

“…For example, the oxidative P450 enzyme system was induced in S. griseus upon growing on soybean our as enriched media. [30][31][32][33][34] Genistein, the major component of soybean our, was responsible for induction of enzyme expression although it inhibited cell growth due to its bacteriostatic effect. 35 In a study related to hydroxylation of vitamin D 3 derivatives catalyzed by S. sclerotialus FERM BP-1370 and S. roseosporus FERM BP-1574 grown in two different media, P450 enzyme was produced only in the enriched medium containing bacto-soytone, corn steep liquor and a high concentration of glucose.…”

“…This evokes cells to express enzymes responsible for substrate conversion or metabolism to less toxic compounds as has been reported for transformation of several substrates using the whole cells of Streptomyces. 32,[37][38][39] Streptomyces species might transform low concentrations of substrates unless the cells are induced by specic substrates. Remarkably, the resting (recombinant) cells of S. avermitilis, expressing isoavone Omethyl transferase, oxidized daidzein at a concentration not exceeding 100 mM.…”

“…We have recently checked the capability of S. glaucescens GLA.0 for asymmetric sulfoxidation using thioanisole (62) as a prochiral aromatic sulfide model. 32 The substrate was converted to the pure isomer of phenyl methyl sulfoxide ( R -PMSO) (63) at a high yield of 90% and excellent ee exceeding 99% employing the growing bacterial culture. Different parameters were varied to optimize the reaction conditions reaching higher yields of the product and smaller amounts of phenyl methyl sulfone (64) as a byproduct.…”