期刊
PROCESS BIOCHEMISTRY
卷 98, 期 -, 页码 76-82出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.procbio.2020.08.003
关键词
Adaptive evolution; Acid tolerance; Actinobacillus succinogenes; Succinic acid; Membrane composition
资金
- National Key R&D Program of China [2019YFA0905700]
- National Natural Science Foundation of China [21706124, 21978130]
- Natural Science Foundation of Jiangsu Province [BK20170997]
- Jiangsu Synergetic Innovation Center for Advanced Bio-Manufacture Postgraduate Research & Practice Innovation Program of Jiangsu Province
- National Students' Platform for Innovation and Entrepreneurship Training Program [201910291168Y]
Fermentation at low pH is an efficient way to improve the competitiveness of biological succinic acid-producing process. Actinobacillus succinogenes shows good performance of succinic acid production under anaerobic conditions, but its succinic acid production capability at the low-pH is inefficient due to the poor acid resistance. Herein, a mutant A. succinogenes BC-4 with improved cell growth and succinic acid production under weak acid conditions was obtained by adaptive evolution. The specific growth rate and succinic acid production of BC-4 reached 0.13 g/L/h and 20.77 g/L, which were increased by 3.25- and 2.95- fold, respectively compared with the parent strain under anaerobic condition at pH 5.8. The activities of specific enzymes with ATP generation were significantly enhanced under weak acidic conditions, resulting in 1.28-fold increase in the maximum ATP level. Membrane fatty acid composition analysis demonstrated that the ratio of saturated to unsaturated fatty acids was decreased from 1.62 to 1.44 in mutant BC-4, leading to improved intracellular pH homeostasis. Furthermore, the change from long-chain to median-chain fatty acid might lower the permeability of H+ into cytoplasm for survival under acid stress. These results indicated that A. succinogenes BC-4 is a promising candidate for succinic acid production under weak acid condition.
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