Highly enantiomeric reduction of acetophenone and its derivatives by locally isolated Rhodotorula glutinis

Abstract

Ninety isolates of microorganisms belonging to different taxonomical groups (30 bacteria, 20 yeast, and 40 fungi) were previously isolated from various samples. These isolates were screened as reducing agents for acetophenone 1a to phenylethanol 2a. It was found that the isolate EBK-10 was the most effective biocatalyst for the enantioselective bioreduction of acetophenone. This isolate was identified as Rhodotorula glutinis by the VITEK 2 Compact system. The various parameters (pH 6.5, temperature 32 degrees C, and agitation 200 rpm) of the bioreduction reaction was optimized, which resulted in conversions up to 100% with >99% enantiomeric excesses (ee) of the S-configuration. The preparative scale bioreduction of acetophenone 1a by R. glutinis EBK-10 gave (S)-1-phenylethanol 2a in 79% yield, complete conversion, and >99% ee. In addition, R.glutinis EBK-10 successfully reduced various substituted acetophenones.

Highly Enantioselective Production of Chiral Secondary Alcohols with Candida zeylanoides as a New Whole Cell Biocatalyst

“…Isolated enzymes are extremely selective and recyclable catalysts, but are usually very expensive and not readily accessible due to the limited availability of cosubstrates and cofactors of the biocatalyst . On the other hand, whole cells are small factories, especially advantageous since they are equipped with all the metabolic ways for the regenerations of necessary cofactors, well protected within their natural cellular environment and several different microorganisms were successfully shown to be used for these biotransformation reactions . These examples showed that different microorganisms belonging to bacteria, yeast or fungi can act as different biotransformation agents with different final yields and ee values and finding new microbial species with biotransformation potential is crucial.…”

Synthesis of Enantiomerically Enriched Drug Precursors by Lactobacillus paracasei BD87E6 as a Biocatalyst

“…Compound 2h can be used for the synthesis of ( S )‐rivastigmine which has a great potential for the treatment of Alzheimer's disease. Optically active phenylethanol and its derivatives are useful building blocks for the synthesis of complex molecules as the alcohol functionality can be easily transformed, without racemization into other functional groups . ( S )‐Rivastigmine synthesis has been reported in the literature in 7 steps, but ( S )‐rivastigmine could be synthesized starting from the ( R )‐ 2h compound in both less steps and cheaper.…”

“…Optically active phenylethanol and its derivatives are useful building blocks for the synthesis of complex molecules as the alcohol functionality can be easily transformed, without racemization into other functional groups. [23] (S)-Rivastigmine synthesis has been reported in the literature [13] in 7 steps, but (S)rivastigmine could be synthesized starting from the (R)-2h compound in both less steps and cheaper. In addition, a chiral molecule was synthesized in small scale with 99% enantioselectivity for the synthesis of (S)-rivastigmine with the commercially purchased pure enzyme in the literature.…”

Preparation of Enantiomerically Pure (S)‐(−)‐1‐(1′‐naphthyl)‐ethanol by the Fungus Alternaria alternata

“…One methodology that has been very successful and has become a common one for preparation of chiral compounds is biotransformation. An extensive collection of biocatalysts have been reported to assist biotransformations . Biocatalysts have many advantages compared to chemical catalysts.…”

“…An extensive collection of biocatalysts have been reported to assist biotransformations. [4][5][6] Biocatalysts have many advantages compared to chemical catalysts. Chemical catalysts produce toxic waste and a large range of by-products, whereas biocatalysts are biodegradable, and provide a clean and environment-friendly way to carry out chemical reactions under mild reaction conditions and great selectivity for the substrate.…”