Natural Products and Glyco-Biotechnology Research Group, Liaoning Provincial Key Laboratory of Carbohydrates, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, People's Republic of China.
World J Microbiol Biotechnol. 2013 Oct;29(10):1923-30. doi: 10.1007/s11274-013-1357-6. Epub 2013 Apr 27.
Lactobacillus brevis 3-A5 was isolated and expected to produce mannitol efficiently by regulating pH in batch and fed-batch fermentations. In 48 h batch fermentations with free and constant pH, the optimal pH for cell growth and mannitol production in the first 24 h of incubation was 5.5, whereas that for mannitol production in the second 24 h of incubation was 4.5. To achieve high cell density and mannitol yield simultaneously, a dual-stage pH control strategy was proposed based on the kinetic analysis of mannitol production. The pH value was controlled at 5.5 for the first 12 h of fermentation and subsequently shifted to 4.5 until the fermentation was completed. Under dual-stage pH control fermentation, a 103 g/L yield of mannitol with a volumetric production rate of 3.7 g/L/h was achieved after 28 h. The dual-stage pH control fed-batch fermentation strategy was further developed to improve mannitol yield, wherein the yield increased by 109 % to 215 g/L after 98 h of fermentation. This value is the highest yield of mannitol ever reported using L. brevis.
短乳杆菌 3-A5 被分离出来，并通过在分批和补料分批发酵中调节 pH 值，有望高效生产甘露醇。在自由恒 pH 值的 48 h 分批发酵中，细胞生长和甘露醇生产的最佳初始 24 h pH 值为 5.5，而随后 24 h 的最佳 pH 值为 4.5。为了同时实现高细胞密度和甘露醇产量，基于甘露醇生产的动力学分析，提出了一种两级 pH 控制策略。发酵前 12 h 将 pH 值控制在 5.5，随后降至 4.5，直至发酵结束。在两级 pH 控制发酵下，经过 28 h 发酵可获得 103 g/L 的甘露醇产率，比体积产率为 3.7 g/L/h。进一步开发了两级 pH 控制补料分批发酵策略来提高甘露醇产量，发酵 98 h 后产量增加 109%，达到 215 g/L。这是使用短乳杆菌生产甘露醇的最高产量。
