响应面分析法和氮源改进优化L-赖氨酸发酵工艺

Fermentation improvement of L-lysine by response surface analysis and additional nitrogen source

为提高赖氨酸发酵的产酸浓度、糖酸转化率等发酵指标,通过Plackett-Burman实验设计筛选出培养基中对赖氨酸发酵影响最大的成分为蛋氨酸、糖蜜和谷氨酸,再通过响应面设计实验对这3种成分进行优化,得到最适含量为蛋氨酸0.195g/L,糖蜜15.70mL/L,谷氨酸0.215g/L,赖氨酸浓度从1.90g/100mL提高至2.25g/100mL。发酵培养基中加入10g/L的(NH4)2SO4作为改进氮源,赖氨酸浓度可进一步提高至2.41g/100mL,发酵周期由30h缩短至25h。通过优化培养基和改进氮源,可以显著降低赖氨酸的生产成本,提高产品收益。

To increase L-lysine concentration and conversion ratio, methionine, molasses and glutamate proved to be the most significant factors in the fermentative medium by Placket-Burman experiments.In response surface methodology design experiments, these three factors＇ optimum concentrations were respectively 0.195g/L, 15.70mL/L and 0.215g/L, when L-lysine production was improved from 1.90g/100mL to 2.25g/100mL.When additional lOg/L（NH4） 2SO4 was added into the fermentative medium, L-lysine production was further increased to 2.41g/lOOmL,and fermentation period was decreased from 30 hours to 25 hours.By optimizing medium and improvirg nitrogen source, productior cost of L-lysie was greatly decreased.