Screening of microorganisms producing cold-active oxidoreductases to be applied in enantioselective alcohol oxidation. An Antarctic survey

Combinatory Library of Microorganisms in the Selection of Reductive Activity Applied to a Ketone Mixture: Unexpected Highlighting of an Enantioselective Oxidative Activity

Biocatalytic processes are increasingly used in organic synthesis for the preparation of targeted molecules or the generation of molecular diversity. The search for the biocatalyst is often the bottleneck in the development of the process. We described a combinatorial approach for the selection of active strains from a library of microorganisms. In order to show the potential of the method we applied it to a mixture of substrates. We were able to select yeast strains capable of producing enantiopure alcohol from corresponding ketones with very few tests and highlight tandem reaction sequences involving several microorganisms. We demonstrate an interest in the kinetic study and the importance of incubation conditions. This approach is a promising tool for generating new products.

Degraded Metabolites of Phlorizin Promote Germination of Valsa mali var. mali in its Host Malus spp

Plant pathogenic fungi are able to utilize the principal metabolites of their hosts, which is one reason pathogens can so seriously harm the plants, although the mechanisms behind this utilization are not always clear. Valsa mali var. mali is a pathogenic fungus specific to the plant genus Malus. The fungus can seriously endanger apple crops and has caused serious economic losses. Phlorizin (1), the principal component in the stems, roots, and leaves of Malus pumila and M. sieversii, was able to promote spore germination of Valsa mali var. mali (Vmm-30) significantly over 120-168 h in a non-nutritional suspension. Compared with the control, the concentrations of nine phenolic compounds (3-11) in the stems of M. pumila increased after inoculation with Vmm-30. Moreover, compounds 3, 4, and 9-11 were able to promote the germination of Vmm-30 spores over 24-36 h, which was a significantly shorter time than that of phlorizin. High-performance liquid chromatography with diode-array detection (HPLC-DAD) and ultraperformance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) analyses further suggested that compounds 2-11 were the degradation products of phlorizin (1) and are produced through carbon oxidation cracking, decarboxylation, and oxidation reactions. This suggests that the degradation of phlorizin is able to effectively promote the growth of Vmm-30. The Vmm-30 strain is therefore able to utilize the principal metabolite phlorizin to generate a series of degradation products, which further promote its germination and the infection of its host plants in the genus Malus.

Applications of Marine-Derived Microorganisms and Their Enzymes in Biocatalysis and Biotransformation, the Underexplored Potentials

Biodiversity has been explored in the search for novel enzymes, including forests, savannas, tundras, deserts, and finally the sea. Marine microorganisms and their enzymes are capable of being active in high-salt concentration, large range of temperature, and high incidence of light and pressure, constituting an important source of unique biocatalysts. This review presents studies employing whole-cell processes of marine bacteria and fungi, aiming for new catalysts for different reactions in organic synthesis, such as reduction, oxidation, hydroxylation, hydrolysis, elimination, and conjugation. Genomics and protein engineering studies were also approached, and reactions employing isolated enzymes from different classes (oxidoreductases, hydrolases, lyases, and ligases) were described and summarized. Future biotechnological studies and process development should focus on molecular biology for the obtention of enzymes with interesting, fascinating and enhanced properties, starting from the exploration of microorganisms from the marine environment. This review approaches the literature about the use of marine-derived bacteria, fungi, and their enzymes for biocatalytic reactions of organic compounds, promoting a discussion about the possibilities of these microorganisms in the synthesis of different substances.

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

Here, we report the 4.12-Mb draft genome sequence of Arthrobacter sp. strain 7749, isolated from marine sediment samples of the Antarctic Peninsula, using enriched medium with (RS)-1-(4-phenyl)-ethanol as a carbon source. This genome sequence will provide relevant information for applications in enantioselective alcohol oxidation to improve industrial catalytic processes.

Resolution of enantiopure (S)-1-(1-napthyl) ethanol from racemic mixture by a novel Bacillus cereus isolate

Chiral intermediates have wide application and high demand in pharmaceutical, agricultural, and other biotechnological industries for the preparation of bulk drug substances or fine chemicals. (S)-1-(1-napthyl) ethanol is an important synthetic intermediate of mevinic acid analog and a potential inhibitor of 3-hydroxy methyl glutaryl coenzyme A reductase enzymes which is rate limiting for cholesterol synthesis. The present study focuses on the resolution of (RS)-1-(1-napthyl) ethanol using whole cell biotransformation approach. The screening of microbial strains for the specific conversion were performed by the enrichment techniques using (RS)-1-(1-napthyl) ethanol. Evaluation of resolution, i.e., the enantioselective conversion of (R)-1-(1-napthyl) ethanol into 1-acetonapthone and production of (S)-1-(1-napthyl) ethanol with high purity were carried out. Among the isolates, a novel strain Bacillus cereus WG3 was found to be potent for the resolution and conversion of (S)-1-(1-napthyl) ethanol. This strain showed 86% conversion of (R)-1-(1-napthyl) ethanol and 95% yield of S-1-(1-napthyl) ethanol with 80% ee after 24 h. Further, the optimization of biotransformation reactions was carried out and the optimal parameters were found to be pH 7.0 and temperature 30 °C.

Lipase-catalyzed kinetic resolution of aryltrimethylsilyl chiral alcohols

Lipase-catalyzed kinetic resolution of aryltrimethylsilyl chiral alcohols through a transesterification reaction was studied. The optimal conditions found for the kinetic resolution of m- and p-aryltrimethylsilyl chiral alcohols, led to excellent results, high conversions (c = 50%), high enantiomeric ratios (E > 200) and enantiomeric excesses for the remaining (S)-alcohol and (R)-acetylated product (>99%). However, kinetic resolution of o-aryltrimethylsilyl chiral alcohols did not occur under the same conditions applied to the other isomers.