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A homofermentative Bacillus sp. BC-001 and its performance as a potential L-lactate industrial strain

Thitiprasert, Sitanan, Kodama, Kentaro, Tanasupawat, Somboon, Prasitchoke, Phatthanon, Rampai, Tanapawarin, Prasirtsak, Budsabathip, Tolieng, Vasana, Piluk, Jiraporn, Assabumrungrat, Suttichai, Thongchul, Nuttha
Bioprocess and biosystems engineering 2017 v.40 no.12 pp. 1787-1799
Bacillus (bacteria), calcium, fermentation, fermenters, glucose, heat tolerance, lactic acid, pH, saccharification, starch, sucrose
Bacillus sp. BC-001 was first reported as a potent thermotolerant and homofermentative strain for an industrial-scale L-lactate production. In a flask culture, this isolate fermented both glucose and sucrose to lactate with high yield (0.96 and 0.87 g/g) and productivity (2.8 and 2.6 g/L h), respectively. The higher lactate production performance was obtained in the simultaneous saccharification and fermentation of liquefied starch (150.1 g/L final titer, 0.98 g/g yield, 3.2 g/L h productivity) and the fed-batch glucose fermentation (139.9 g/L final titer, 0.96 g/g yield, 2.9 g/L h productivity). Significant increase in lactate productivity (5.5–6.1 g/L h) was obtained from the high/heavy-inoculum seed in the stirred tank fermentor. Both calcium bases and monovalent bases were successfully employed for pH control during lactate fermentation by this isolate resulting in a versatile and simple operation. By the two-phase fermentation using the high/heavy-inoculum seed of BC-001, the fermentation reproducibility was acquired toward the pilot-scale fermentors.