Matta-el-Ammouri G, Janati-Idrissi R, Junelles A M, Petitdemange H, Gay R
Biochimie. 1987 Feb;69(2):109-15. doi: 10.1016/0300-9084(87)90242-2.
The actions of butyric and acetic acids on acetone-butanol fermentation are investigated. Production of butyric and acetic acids are controlled by the extracellular concentrations of both acids: acetic acid added to the medium inhibits its own formation but has no effect on butyric acid formation, and added butyric acid inhibits its own formation but not that of acetic acid. The ratio of end metabolites depends upon acetic and butyric acid quantities excreted during the fermentation. In contrast to acetic acid, which specifically increases acetone formation, butyric acid increases both acetone and butanol formations. Acetate and butyrate kinase activities were also examined. Both increase at the start of fermentation and decrease when solvents appear in the medium. Coenzyme A transferase activity is weak in the acidogenic phase and markedly increases in the solvent phase. Acetic and butyric acids appear to be co-substrates. On the basis of these results, a mechanism of acetic and butyric acid pathways, coupled to solvent formation by C. acetobutylicum glucose fermentation is proposed.
研究了丁酸和乙酸对丙酮-丁醇发酵的作用。丁酸和乙酸的产生受两种酸的细胞外浓度控制：添加到培养基中的乙酸会抑制其自身的形成，但对丁酸的形成没有影响，而添加的丁酸会抑制其自身的形成，但不会抑制乙酸的形成。终产物的比例取决于发酵过程中分泌的乙酸和丁酸的量。与特异性增加丙酮形成的乙酸不同，丁酸会增加丙酮和丁醇的形成。还检测了乙酸激酶和丁酸激酶的活性。两者在发酵开始时增加，当培养基中出现溶剂时降低。辅酶A转移酶活性在产酸阶段较弱，在溶剂阶段显著增加。乙酸和丁酸似乎是共同底物。基于这些结果，提出了与丙酮丁醇梭菌葡萄糖发酵形成溶剂相关的乙酸和丁酸途径的机制。
