Enhanced biotransformation of carbon tetrachloride by Acetobacterium woodii upon addition of hydroxocobalamin and fructose

The objective of this study was to evaluate the effect of hydroxocobalamin (OH-Cbl) on transformation of high concentrations of carbon tetrachloride ( CT) by Acetobacterium woodii (ATCC 29683). Complete transformation of 470 m u M (72 mg/liter [aqueous]) CT was achieved by A. woodii within 2.5 days, w hen 10 mu M OH-Cbl was added along with 25.2 mM fructose, This was approxim ately 30 times faster than A. woodii cultures (live or autoclaved) and medi um that did not receive OH-Cbl and 5 times faster than those controls that did receive OH-CM, but either live A. woodii or fructose was missing. CT tr ansformation in treatments with only OH-Cbl was indicative of the important contribution of nonenzymatic reactions. Besides increasing the rate of CT transformation, addition of fructose and OH-Cbl to live cultures increased the percentage of [C-14]CT transformed to (CO2)-C-14 (Up to 31%) and C-14-l abeled soluble materials (principally L-lactate and acetate), while decreas ing the percentage of CT reduced to chloroform and abiotically transformed to carbon disulfide. (CS2)-C-14 represented more than 35% of the [C-14]CT i n the presence of reduced medium and OH-Cbl. Conversion of CT to CO was a p redominant pathway in formation of CO2 in the presence of live cells and ad ded fructose and OH-Cbl. These results indicate that the rate and distribut ion of products during cometabolic transformation of CT by A. woodii can be improved by the addition of fructose and OH-Cbl.