Reductive degradation of pyrazine-2-carboxylate by a newly isolated Stenotrophomonas sp. HCU1.

A bacterium growing on pyrazine-2-carboxylate broth was isolated, purified and identified as a strain of Stenotrophomonas sp. based on polyphasic taxonomic analyses and designated as strain HCU1. 16S rRNA gene sequence of strain HCU1 showed 98.7% sequence similarity with the type strain of Stenotrophomonas maltophilia belonging to Gammaproteobacteria. Growth of strain HCU1 was demonstrated when pyrazine-2-carboxylate was used as a sole source of nitrogen. Ring reduction of pyrazine-2-carboxylate was shown as increase in absorbance at 268 nm and the reduced product was confirmed as 1,2,5,6-tetrahydropyrazine-2-carboxylate, while a ring opened product, 2-amino-2-hydroxy-3-(methylamino) propanoic acid (with a loss in carbon atom), indicated a reductive degradation of pyrazine-2-carboxylate by strain HCU1.