REACTOR COMPARISONS FOR THE BIODEGRADATION OF THIODIGLYCOL, A PRODUCTOF MUSTARD GAS HYDROLYSIS

An environmentally benign method for the mineralization of sulfur must ard has been proposed involving chemical hydrolysis of sulfur mustard to thiodiglycol, and then the biological degradation of thiodiglycol t o generate biomass and gaseous carbon dioxide. Alcaligenes xylosoxidan s (SH91) was isolated based on its ability to utilize thiodiglycol as a sole carbon source. This article compares different biological react or designs and experimentally assesses their relative effectiveness in degrading thiodiglycol using pure cultures of SH91. The reactor confi gurations studied are batch, continuous stirred-tank reactor (CSTR), a nd CSTR with cell recycle. From the results, it is clear that the CSTR with cell recycle offers superior performance for a given residence t ime or volume. These pure culture data are necessary for accurate desi gn of a pilot-scale system where mixed cultures will be employed becau se of a possible incomplete chemical hydrolysis step.