副干酪乳杆菌ZG19发酵烟草废水产L-乳酸的响应面优化

Optimization of fermentation process conditions of Lactobacillus paracasei ZG19 using tobacco wastewater for L-lactic acid production with response surface methodology

烟草废水中含有大量的可溶性糖、含氮化合物和矿物质等营养成分。为资源化利用烟草废水,以本实验室分离并保藏的一株产L-乳酸的副干酪乳杆菌(Lactobacillus paracasei)ZG19为发酵菌株,以烟草废水为发酵底料,L-乳酸产量为响应值,采用响应面法(RSM)优化发酵工艺。通过Plackett-Burman试验筛选出对L-乳酸产量影响最显著的因素,进一步设计爬坡试验逼近最优区域,然后设计Box-Behnken响应面优化,分析并确定最佳发酵工艺。结果表明,在发酵温度39℃、发酵时间30 h、菌种接种量10%条件下,得到L-乳酸实际产量为15.16 g/L,与预测值(15.35 g/L)拟合度达到98.76%,L-乳酸产量显著提高。因此,采用此方法得到的优化工艺合理而有效,具有实际应用价值。

Tobacco wastewater contains large amounts of soluble sugar, nitrogen compounds, minerals and other nutrients. For resource utilization of tobacco wastewater, using L-lactic acid-producing Lactobacillus par^acasei ZG19 which isolated and preserved in laboratory as fermentation strain, with tobacco wastewater as fermentation substrate and L-lactic acid yield as response value, the fermentation process was optimized using response surface methodology （RSM）. By Plackett-Burman （PB） design, the most significant factors affecting the yield of L-lactic acid were screened. Based on the results of PB design, the steepest ascent experiment was designed to approach the optimal region, and by BBD-RSM optimization, the optimal fermentation process was analyzed and determined. The results showed that with conditions of inoculum 10 %, fermentation temperature 39 ^ and time 30 h, the actual yield of L-lactic acid was 15.16 g/L and the fitting degree was 98.76% with the predicted value of 15.35 g/L. The yield of L-lactic acid increased significantly after optimization. Therefore, the optimal fermentation process was reasonable and available, which had practical applica-tion value.