Hashsham S A, Freedman D L
Center for Microbial Ecology and Department of Civil and Environmental Engineering, Michigan State University, E. Lansing, Michigan 48824, USA.
Appl Environ Microbiol. 1999 Oct;65(10):4537-42. doi: 10.1128/AEM.65.10.4537-4542.1999.
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 microM (72 mg/liter [aqueous]) CT was achieved by A. woodii within 2.5 days, when 10 microM OH-Cbl was added along with 25.2 mM fructose. This was approximately 30 times faster than A. woodii cultures (live or autoclaved) and medium that did not receive OH-Cbl and 5 times faster than those controls that did receive OH-Cbl, but either live A. woodii or fructose was missing. CT transformation 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 [(14)C]CT transformed to (14)CO(2) (up to 31%) and (14)C-labeled soluble materials (principally L-lactate and acetate), while decreasing the percentage of CT reduced to chloroform and abiotically transformed to carbon disulfide. (14)CS(2) represented more than 35% of the [(14)C]CT in the presence of reduced medium and OH-Cbl. Conversion of CT to CO was a predominant pathway in formation of CO(2) in the presence of live cells and added fructose and OH-Cbl. These results indicate that the rate and distribution of products during cometabolic transformation of CT by A. woodii can be improved by the addition of fructose and OH-Cbl.
本研究的目的是评估羟钴胺素（OH-Cbl）对伍氏醋杆菌（ATCC 29683）转化高浓度四氯化碳（CT）的影响。当添加10 microM OH-Cbl和25.2 mM果糖时，伍氏醋杆菌在2.5天内实现了470 microM（72 mg/升[水相]）CT的完全转化。这比未添加OH-Cbl的伍氏醋杆菌培养物（活的或高压灭菌的）和培养基快约30倍，比添加了OH-Cbl但缺少活的伍氏醋杆菌或果糖的对照组快5倍。仅用OH-Cbl处理时CT的转化表明了非酶促反应的重要贡献。除了提高CT的转化速率外，向活培养物中添加果糖和OH-Cbl还增加了[(14)C]CT转化为(14)CO(2)（高达31%）和(14)C标记的可溶性物质（主要是L-乳酸和乙酸盐）的百分比，同时降低了CT还原为氯仿和非生物转化为二硫化碳的百分比。在存在还原培养基和OH-Cbl的情况下，(14)CS(2)占[(14)C]CT的35%以上。在存在活细胞、添加的果糖和OH-Cbl的情况下，CT转化为CO是形成CO(2)的主要途径。这些结果表明，添加果糖和OH-Cbl可以提高伍氏醋杆菌对CT共代谢转化过程中产物的速率和分布。
