Frank C, Schwarz U, Matthies C, Drake H L
Department of Ecological Microbiology, BITOEK, University of Bayreuth, D-95440 Bayreuth, Germany.
Arch Microbiol. 1998 Nov;170(6):427-34. doi: 10.1007/s002030050663.
When the acetogen Clostridium formicoaceticum was cultivated on mixtures of aromatic compounds (e.g., 4-hydroxybenzaldehyde plus vanillate), the oxidation of aromatic aldehyde groups occurred more rapidly than did O-demethylation. Likewise, when fructose and 4-hydroxybenzaldehyde were simultaneously provided as growth substrates, fructose was utilized only after the aromatic aldehyde group was oxidized to the carboxyl level. Aromatic aldehyde oxidoreductase activity was constitutive (activities approximated 0. 8 U mg-1), and when pulses of 4-hydroxybenzaldehyde were added during fructose-dependent growth, the rate at which fructose was utilized decreased until 4-hydroxybenzaldehyde was consumed. Although 4-hydroxybenzaldehyde inhibited the capacity of cells to metabolize fructose, lactate or gluconate were consumed simultaneously with 4-hydroxybenzaldehyde, and lactate or aromatic compounds lacking an aldehyde group were utilized concomitantly with fructose. These results demonstrate that (1) aromatic aldehydes can be utilized as cosubstrates and have negative effects on the homoacetogenic utilization of fructose by C. formicoaceticum, and (2) the consumption of certain substrates by this acetogen is not subject to catabolite repression by fructose.
当乙酸生成菌甲酸乙酸梭菌在芳香族化合物混合物（如4-羟基苯甲醛加香草酸）上培养时，芳香醛基团的氧化比O-去甲基化发生得更快。同样，当同时提供果糖和4-羟基苯甲醛作为生长底物时，果糖仅在芳香醛基团被氧化到羧基水平后才被利用。芳香醛氧化还原酶活性是组成型的（活性约为0.8 U mg-1），并且在果糖依赖性生长期间添加4-羟基苯甲醛脉冲时，果糖的利用速率降低，直到4-羟基苯甲醛被消耗。虽然4-羟基苯甲醛抑制细胞代谢果糖的能力，但乳酸或葡萄糖酸盐与4-羟基苯甲醛同时被消耗，并且乳酸或缺乏醛基的芳香族化合物与果糖同时被利用。这些结果表明：（1）芳香醛可作为共底物利用，并对甲酸乙酸梭菌果糖的同型乙酸生成利用产生负面影响；（2）这种乙酸生成菌对某些底物的消耗不受果糖的分解代谢物阻遏作用。
