Discovery of Microbial "Aldoxime-Nitrile Pathway" and Its Application to Nitrile Synthesis

点击翻译按钮获取中文摘要

Discoveries of an accumulation of amides by the use of new bacterial enzyme "nitrile hydratase" led to the successful application of nitrile hydratase to the industrial production of various amides. Nitrile hydratase e has become one of the most important industrial enzymes. We have been successful in the enzymatic synthesis of nitriles from aldoximes by using the new microbial enzyme aldoxime dehydratase, which works in newly proposed "Aldoxime-Nitrile Pathway".(1) The distribution of aldoxime dehydratase in microorganisms was shown to be relatively wide among microorganisms.(2) Phenylacetaldoxime dehydratase has been purified, characterized and its gene cloned from Bacillus sp. Strain OxB-1 and expressed in E. coli JM 109.(3) We screened for microorganisms to convert E-pyridine-3-aldoxime to the corresponding nitrile and isolated Rhodococcus sp. YH3-3 from soil. The cells containing the inducible enzyme catalyzed the stoichiometric dehydration of aldoximes to form nitriles. Various nitriles were synthesized at preparative scales from 10-100 mM aldoximes under optimized reaction conditions. We also optimized conditions for large-scale synthsis of aryl-and alkyl-nitriles in high yields from the corresponding aldoximes by Escherichia coli JM109/poxd90F cells expressing phenylacetaldoxime dehydratase from Bacillus sp. strain OxB-1. We synthesized various ary1- and alky1-nitriles from the corresponding aldoximes by the transformant cells.(4) Aldoxime dehydratase has been purified, characterized and its gene cloned and sequenced from Rhodococcus globerulus A-4 and expressed in E. coli JM 109. The gene for the enzyme was shown to be linked with the nitrile hydratase gene.