Urocanic Acid-producting Mutants of Brevibacterium ammoniagenes

Abstract

A urocanase-deficient mutant KY 10550 was derived from a wild-type strain of Brevibacterium ammoniagenes ATCC 6872. It quantitatively converted L-histidine into urocanic acid.
A 2-thiazo-DL-alanine (histidine analog)-resistant derivative of KY 10550, designated as UTA-55, accumulated 200 μg/ml of urocanic acid in a culture medium containing 15% sugar without supplemention of L-histidine. The urocanic acid productivity of UTA-55 was improved by successive addition of resistant markers; higher histidine analogs-resistance, purine analogs-resistance and streptomycin-resistance. Finally selected mutant strain FTGSA-7 accumlated 7.3mg/ml of urocanic acid.
In the cource of the strain improvement, the mutants which accumulate L-histidine, imidazolelactate, imidazoleacetate or other substances were obtained.