摘要
为了解循环酶解过程对玉米秸秆酶解糖化的影响及循环酶解液对隐球酵母SCTCC300292发酵产油脂的影响,通过HPLC检测玉米秸秆循环酶解液的糖组分及含量,比较菌株SCTCC300292利用循环酶解液及同等糖浓度合成培养基的油脂发酵效果.结果显示:蒸汽爆破玉米秸秆的循环酶解过程使酶的添加量降低了40%,前5轮酶解液的糖组分和含量基本一致,葡萄糖、木糖和阿拉伯糖的平均含量为33.63 g/L、10.55 g/L和4.02 g/L,最后一步酶解虽然不添加新的酶和底物仍继续产糖,整个酶解过程的糖转化率由74.84%提高至82.32%,糖得率由479.4 g/kg提高至527.36 g/kg,且产糖速率较高约2.20 g L^(-1) h^(-1).菌株SCTCC300292利用玉米秸秆的循环酶解液完成了6轮油脂发酵,前5轮发酵的生物量、油脂产量和油脂含量基本一致且平均值分别为10.84 g/L、5.08 g/L和46.86%,其最终油脂得率提高至54.6 g/kg.本研究表明快速循环酶解过程可促进玉米秸秆的彻底水解并降低生物转化成本,可为进一步实现高效、经济、环保的生物炼制提供参考.
The aim was to study the effect of the cycle process of enzymatic hydrolysis on the enzymatic saccharification of corn stover, and on the microbial lipid production performance of the oleaginous yeast Cryptococcus podzolicus SCTCC300292 using the enzymatic hydrolysate for cycles. The sugar component of the enzymatic hydrolysate was determined by HPLC. Lipid fermentation reactions of strain SCTCC300292 using the corn stover hydrolysate for cycles and synthetic media were compared. The cycle process of enzymatic hydrolysis by recycling enzymatic waste was demonstrated on steam explosion–pretreated corn stover for six cycles. Enzyme loadings were reduced by 40% and resulted in consistent sugar concentration in the first five cycles, where the average concentrations of glucose, xylose, and arabinose were 33.63 g/L, 10.55 g/L, and 4.02 g/L, respectively. The enzymatic hydrolysis at the last step resulted in lower sugar concentration because no free biomass or enzymes were added. Throughout the process of enzymatic hydrolysis, sugar conversion increased from 74.84% to 82.32%, and sugar yield increased from 479.4 g/kg to 527.36 g/kg with a high sugar release rate （2.20 g L-1 h-1）. The lipid fermentation by strain SCTCC300292 using the enzymatic hydrolysate for cycles showed consistent lipid production in the first five cycles, where the mean values of biomass, lipid yield, and lipid content were 10.56 g/L, 5.03 g/L, and 47.60%, respectively, and the total lipid coefficient reached 54.6 g/kg in the whole biorefinery process. The results of this study indicate that the cycle process of enzymatic hydrolysis by recycling of enzymatic waste may promote hydrolysis of corn stover completely and reduce the costs of bioconversion; these data provided insights for improvement of the biorefinery.
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2017年第6期984-989,共6页
Chinese Journal of Applied and Environmental Biology
基金
"十二五"科技支撑计划项目(2014BAD02B02)
国家微生物资源平台项目(NIMR-2016-8)
四川省科技厅项目(2014GZX0005
18ZDYF1802
2017TJPT0001)资助~~
关键词
玉米秸秆
循环酶解
隐球酵母
油脂发酵
corn stover
enzymatic hydrolysis cycle
Cryptococcus podzolicus
lipid fermentation
