ACIDIC CONDITIONS ARE NOT OBLIGATORY FOR ONSET OF BUTANOL FORMATION BY CLOSTRIDIUM-BEIJERINCKII (SYNONYM, CLOSTRIDIUM-BUTYLICUM)
ACIDIC CONDITIONS ARE NOT OBLIGATORY FOR ONSET OF BUTANOL FORMATION BY CLOSTRIDIUM-BEIJERINCKII (SYNONYM, CLOSTRIDIUM-BUTYLICUM)
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DOI：
10.1128/aem.46.2.321-327.1983
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发表时间：
1983-01-01
影响因子：
4.4
通讯作者：
CHEN, JS
中科院分区：
文献类型：
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作者：
GEORGE, HA;CHEN, JS
在间歇培养条件下，研究了可能引发丁醇生产代谢转变的因素。beijerinckii（synoynm，C.丁基）VPI 13436。维持在pH 6.8的培养物产生的丁醇几乎与没有pH控制的培养物一样多，这表明无论是培养物pH的变化还是酸性条件本身都不总是需要启动溶剂形成。丁醇生产开始时的乙酸盐和丁酸盐水平取决于维持培养物的pH。维持在pH 6.8的培养物可以通过人工降低pH至5.0或通过添加乙酸盐加丁酸盐而不改变pH来加速溶剂生产（但单独使用两种酸都无效）。溶剂的产生与较慢的生长速率和一般代谢有关，并且没有显示出成熟孢子形成的要求。显然，代谢减慢，这可能是由几个条件，是机械相关的丁醇生产的开始。产溶剂细胞的提取物含有乙酰乙酸脱羧酶活性和较高的NADP+连接的丁醇脱氢酶和较低的氢化酶活性比产酸细胞的提取物。溶剂生产似乎没有涉及催化H2氧化的能力增强。
Factors that may initiate the metabolic transition for butanol production were investigated in batch cultures of C. beijerinckii (synoynm, C. butylicum) VPI 13436. Cultures maintained at pH 6.8 produced nearly as much butanol as those incubated without pH control, indicating that neither a change in the culture pH nor acid conditions per se are always required to initiate solvent formation. Acetate and butyrate levels at the onset of butanol production were dependent on the pH at which the cultures were maintained. Cultures maintained at pH 6.8 could be accelerated into solvent production by artificially lowering the pH to 5.0 or by the addition of acetate plus butyrate without a pH change (but neither acid alone was effective). Solvent production was associated with slower rates of growth and general metabolism, and it did not show a requirement for mature spore formation. Evidently, a slowdown in metabolism, which may be brought about by several conditions, is mechanistically related to the onset of butanol production. Extracts of solvent-producing cells contained acetoacetate decarboxylase activity and higher NADP+-linked butanol dehydrogenase and lower hydrogenase activities than extracts of acid-producing cells. Solvent production did not appear to involve an enhanced ability to catalyze H2 oxidation.