BIOCONVERSION OF MALEIC-ACID TO FUMARIC-ACID BY PSEUDOMONAS-ALCALIGENES STRAIN XD-1

Microorganisms which produce fumaric acid from maleic acid were screen ed. Strain XD-1 was selected as the best strain. Based on its taxonomi cal characteristics, this strain was concluded to be a Pseudomonas alc aligenes strain. Addition of toluene to the reaction mixture enhanced the bioconversion of maleic acid to fumaric acid. The conversion activ ity was stable at up to 45 degrees C. Under the optimum conditions, th e fumaric acid productivity of the strain reached 41.9 g/l at 6 h of i ncubation. However, when the incubation time was extended to more than 6 h, the fumaric acid was converted to L-malic acid.