Biocatalytic transformation of [(2-hydroxyethyl)thio]acetic acid and thiodiglycolic acid from thiodiglycol by Alcaligenes xylosoxydans ssp xylosoxydans (SH91)

A Gram-negative bacterium, Alcaligenes xylosoxydans ssp. xylosoxydans (SH91 ), consumed thiodiglycol (TDG), the nontoxic hydrolysis product of sulfur m ustard, as a primary carbon source and transformed TDG to commercially rele vant chemical pre cure ors, [(2-hydroxyethyl)thio] acetic acid (HETA) and t hiodiglycolic acid (TD GA). Aerobic fed batch and repeated batch experiment s were run to compare the molar yields of HETA and TDGA that result under d ifferent operating policies. In repeated batch experiments, 35% of the TDG was converted to HETA. Under the conventional batch process and a repeated fed batch process, the HETA yields were reduced (21% and 18%, respectively) , while the yield of TDGA was increased (47% and 31%, respectively). This w ork demonstrated that cell growth associated biocatalytic transformations w ere manipulated to achieve a desired byproducts profile through an understa nding of the specific reaction and cell growth kinetics and by altering the reaction operating policy accordingly.