大肠杆菌工程菌利用甘蔗糖蜜发酵产L-乳酸研究

大肠杆菌HBUT-L来源于HBUT-D,因此具有快速利用蔗糖的特性。对HBUT-L利用蔗糖及甘蔗糖蜜发酵产L-乳酸的特性进行了研究。结果表明,该菌株在96 h的发酵过程中,可将100 g/L的蔗糖转化生成60.0 g/L乳酸,转化率达到74.0%,杂酸产量少,具有工业化开发潜力。在玉米浆培养基中可以直接添加未经处理的甘蔗糖蜜,发酵周期持续224 h,发酵液所得乳酸产量为87.0 g/L,发酵液残糖为28.6 g/L,但乳酸产率极低,仅为0.389 g/(L·h),后续将对甘蔗糖蜜预处理工艺进行研究,进一步提高乳酸发酵速度和产量。

L-lactic Acid Fermentation from Engineering Escherichia coli by Using Sugarcane Molasses

Escherichia coli HBUT-L comes from the strain HBUT-D, so it is characterized by the rapid uti1ization of sucrose. In the experiment, the characteristics of L-1actic acid fermentation from Escherichia coli HBUT-L by sugar and sugarcane mo1asses were studied. The resu1ts showed that in 96 h of fermentation process, HBUT-L cou1d convert 100 g/L of sucrose into 60.0 g/L of L(+)-1actic acid, the conversion ratio was 74%, with 1ess production of impurities and deve1opment potentia1 for industria1ization. Untreated sugarcane mo1asses cou1d be direct added into corn steep 1iquor medium, the fermentation 1ast-ed 224 h, and fermentation broth produced 87.0 g/L of L(+)-1actic acid and 28.6 g/L of residua1 sugar, however the yie1d of L-1actic acid was extreme1y 1ow and just 0.389 g/L. Subsequent1y, it needed to research the pretreatment techno1ogy of sugar mo1asses and further increase the speed and yie1d of L(+)-1actic acid fermentation.