餐厨垃圾发酵生产乳酸的工艺优化

Process optimization for lactic acid production from kitchen waste

为提高餐厨垃圾发酵生产乳酸的效率,采用Plackett-Burman和中心复合两种统计试验方法对影响发酵的因素进行初筛和优化.Plackett-Burman实验的结果表明,影响乳酸发酵的正向显著性因素有乳酸菌TD175、糖化酶、吐温80、纤维素酶;灭菌是负显著性因素.通过中心复合试验设计,确定最佳发酵工艺:乳酸菌接种量6.6%,糖化酶160U/g,纤维素酶60U/g,吐温800.08%,温度45℃.最佳工艺条件下发酵40h,乳酸产量能达到66.13g/L,每克干垃圾产乳酸0.53g.餐厨垃圾的乳酸发酵无需灭菌、无需额外营养物,具有良好的经济效益和应用前景.

Plaekett- Burman and central composite designs were employed to screen and optimize the significant factors for the enhancement of lactic acid production from kitchen waste. The results of Plackett - Burman experiments showed that lactic acid bacteria TD175, glucoamylase, tween80 and cellulase were the positive significant factors, while sterilization affected the fermentation negatively. Optimum conditions for the lactic acid fermentation of kitchen waste were determined by central composite design as follows ： TD175 6.6% , glu eoamylase 160 U/g, cellulase 60 U/g, Tween -80 0. 08% and temperature 45 ℃. Under these conditions, lactic acid concentration in the fermentation broth reached 66. 13 g/L after 40 h, and about 0. 53 g lactic acid was produced from one gram of dry kitchen waste. Lactic acid production from kitchen waste need not sterilization operation and extra nutrient, thus it is very economical.