副干酪乳杆菌ZG19发酵烟草废水产L-乳酸的响应面优化

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（Lactobacillusparacasei）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。

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

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 Lactobacillusparacasei 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 application value.