Formation of β-Cyanoalanine by Cyanide-resistant Strain Enterobacter sp. 10-1

Abstract

A cyanide-tolerant strain was isolated from a soil sample, and identified as belonging to the genus Enterobacter. The microorganism accumulated a compound which produced a green color with ninhydrin, in culture fluid containing sodium cyanide and sodium fumarate. This compound was isolated from the culture fluid in crystalline form by using ion exchange resin column chromatography, and was identified as β-cyano-L-alanine (β-CNAla). The compound accumulated in the culture fluid with the growth of the microorganism, and the amount of β-CNAla accumulated depended on the amount of sodium cyanide added. Both intact cells and a cell-free extract of the microorganism catalyzed the formation of β-CNAla from O-acetyl-L-serine with sodium cyanide as substrates. The β-CNAla-forming enzyme was found to be localized in both the cytoplasm and cytoplasmic membrane of this microorganism.