组合微生物利用发酵秸秆产乳酸效果的研究

Effects of combinations of microorganisms on lactic acid production using fermentation straw

为了更好的利用玉米芯、玉米秸秆等农业废弃物,提高其综合利用率,减少传统化学方法及秸秆焚烧过程造成的环境污染,试验采用里氏木霉与鸡腿菇混合发酵产粗酶液降解秸秆等废弃物,再利用米根霉将废弃物转化为乳酸。此试验中以商品纤维素酶处理的玉米芯及秸秆为对照进行乳酸发酵试验。鸡腿菇与里氏木霉按5∶2的接种比例,接种时间间隔为12 h,在26℃,150 r/min培养3 d,此时漆酶酶活比鸡腿菇单独发酵酶活提高106%。用以上两菌混合发酵3 d的粗酶液在50℃,pH 5.0,120 r/min下酶解原材料84 h,酶解得率为55.2%,米根霉再转化酶水解液产乳酸量为3.69 g/L,糖酸转化率为67.40%。

This study investigated the production of ligninase and L-lactic acid from mixed fermentation with Trichoderrna reesei, Coprinus comatus, and Rhizopus oryzae. Under optimal conditions with an inoculation proportion of C. cornatus to T. reesei of 5：2, a time interval of 12 h, shake rotation speed of 150 r/min, after inocubation for 3 d at 26%, the laccase activity reached 3 267.1 U/mL, an increase of 106% compared to single cultures. The agricultural wastes were treated for 84 h with crude enzymes extracted from the mixed fermentation of T. reesei and C. comatus at pH 5.0, 50℃with a shaking speed 120 r/min： A 55.2%hydrolysis rate was obtained. The hydrolysed sugar was transformed into L-lactic acid by R. oryzae. Under optimal conditions, 3.36 g/L L-lactic acid was produced and the sugar conversion rate reached 67.40%.