Dual-phase fermentation enables Actinobacillus succinogenes 130ZT to be a potential role for high-level lactate production from the bioresource

Initial oxygen aeration enabled Actinobacillus succinogenes 130ZT to be regarded as a novel type of lactic-acid-producing strain in subsequent anaerobic cultivation. Lactic acid production increased 32-fold, up to the final titers of 135.6 ± 0.14 g L−1 with an overall yield of 0.96 ± 0.09 g g−1 glucose and 2.94 ± 0.03 g L−1 h−1 productivity. The metabolites at the end of dual-phase fermentation by 130ZT were (in parentheses: the mol end product formed/100 mol glucose) succinic acid (37), acetic acid (69), formic acid (21), and lactic acid (193). Carbon flux distribution shifted toward to lactate in the bi-staged cultivation, where C3 flux increased and C4 flux reduced. The enzyme assay revealed that the lactate dehydrogenase (LDH) activity in dual-phase process was nearly 18-fold higher than the values in mono-phase process.