Screening of Microorganisms Producing Cold-Active Oxidoreductases to Be Applied in Enantioselective Alcohol Oxidation. An Antarctic Survey

Abstract

Several microorganisms were isolated from soil/sediment samples of Antarctic Peninsula. The enrichment technique using (RS)-1-(phenyl)ethanol as a carbon source allowed us to isolate 232 psychrophile/psychrotroph microorganisms. We also evaluated the enzyme activity (oxidoreductases) for enantioselective oxidation reactions, by using derivatives of (RS)-1-(phenyl)ethanol as substrates. Among the studied microorganisms, 15 psychrophile/psychrotroph strains contain oxidoreductases that catalyze the (S)-enantiomer oxidation from racemic alcohols to their corresponding ketones. Among the identified microorganisms, Flavobacterium sp. and Arthrobacter sp. showed excellent enzymatic activity. These new bacteria strains were selected for optimization study, in which the (RS)-1-(4-methyl-phenyl)ethanol oxidation was evaluated in several reaction conditions. From these studies, it was observed that Flavobacterium sp. has an excellent enzymatic activity at 10 °C and Arthrobacter sp. at 15 and 25 °C. We have also determined the growth curves of these bacteria, and both strains showed optimum growth at 25 °C, indicating that these bacteria are psychrotroph.

Enantioselective reduction of flavanone and oxidation of cis- and trans-flavan-4-ol by selected yeast cultures

“…The same selectivity was observed in deracemization of 1-aryl ethanol in the cultures of C. parapsilosis ATCC 7330 [36], Candida albicans CCT 0776 [37] and some bacterial strains [39,40], which proceeded via enantioselective oxidation of the (S)-enantiomer. In our previous research concerning bioreduction of propiophenone we observed that during incubation of propiophenone in the cultures of all tested microorganisms, longer biotransformation time resulted in a drop in a percent content of the S-alcohol, along with an increase in a percent content of the R-alcohol.…”

Lipase-Catalyzed Kinetic Resolution of Aryltrimethylsilyl Chiral Alcohols

“…The enantioenriched alcohols 1b , 1c , 1e and 1f obtained from the bromodesilylation reactions (section 3.4.1) were submitted to chiral GC and HPLC analysis, and the values found for retention times were in agreement with enantiopure samples and those described in the literature for enantioenriched compounds [ 42 , 43 , 44 , 45 ]. The absolute configuration of compounds 2b , 2c , 2e and 2f were attributed by analogy of those found to its bromide derivatives.…”

“…The enantioenriched bromides 1b , 1c , 1e and 1f were submitted to chiral GC and HPLC analysis, and the retention times were compared with those described in the literature [ 42 , 43 , 44 , 45 ]. Thus, absolute configuration of enantioenriched aryltrimethylsilyl ( S )-alcohols and ( R )-acetates were determined by analogy to the results found for the bromophenyl ( S )-alcohols.…”

Draft Whole-Genome Sequence of Psychrotrophic Arthrobacter sp. Strain 7749, Isolated from Antarctic Marine Sediments with Applications in Enantioselective Alcohol Oxidation

“…Arthrobacter sp. strain 7749 was isolated from Antarctic marine sediments based on its ability to oxidize ( RS )-1-phenylethanol derivatives with extremely high selectivity for ( S )-enantiomers at low temperatures ( 4 , 5 ). Thus, the genome report of the psychrotrophic strain 7749 will provide valuable information for the identification of cold-active and enantioselective oxidoreductases.…”