蔗渣发酵生产L-乳酸

Sugarcane baggage for production of L-lactic

酶解是纤维质原料用于生物发酵前的关键步骤。为了找到一种高效、低成本和低能耗的蔗渣酶解工艺,本实验研究了蔗渣酶解的底物浓度、pH、酶用量、温度、时间对蔗渣酶解后还原糖释放量的影响,并对酶解的3个主要因素——温度、pH和酶量进行正交实验分析,最终得到蔗渣浓度为8%,酶液6.9 mL,在温度43.9℃、pH为4.3条件下糖化时间14h,还原糖浓度可达54 g/L以上。将糖化液用于发酵实验,发现干酪乳杆菌N-2在酶解液培养基中45℃发酵120 h乳酸产量达到32.5 g/L;对代谢产物进行高效液相分析发现发酵产物为乳酸,几乎没有其他副产物产生。

Enzymatic saccharification of lignocellulose biomass is critical for microbial fermentation. In order to improve the saccharification efficiency and to reduce the production cost and energy consumption,we assessed the impacts of varying parameters on sugar release from enzymatic digestion of sugarcane baggage,including substrate concentration,pH,enzyme dosage,temperature and time. Specially,the three main factors,pH,enzyme dosage,temperature,were evaluated through orthogonal test method. Results showed that the highest sugar release could reach over 54 g /L for 14 h at 43. 9℃ with 8% of sugarcane baggage,6. 9 mL of enzyme silution and pH of 4. 3. Lactic acid yield reached to 32. 5 g /L at 45℃ for 120 h by Lactobacillus casei N-2. High performance liquid metabolite was used to analyze the production,results showed that the production of the strain was lactic acid,and almost without other by-products.