School of Food and Biological Engineering,Hefei University of Technology
考察小麦秸秆的预处理方式对球拟假丝酵母(Starmerella bombicola)利用其糖化液发酵产槐糖脂(SLs)的影响，并对发酵进行优化。分别选择稀酸预处理(DAP)、NaOH预处理(SHP)和SO3微热爆预处理(STMEP)对小麦秸秆进行预处理，使用纤维素酶酶解糖化后将糖化液用于SLs的发酵，采用补加葡萄糖和活性炭脱毒的方法提高SLs的产量。结果显示，SHP最利于小麦秸秆的酶解糖化，所得糖化液中葡萄糖含量达61.30 g/L，其次为STMEP和DAP，葡萄糖含量分别为48.33 g/L和40.00 g/L。STMEP糖化液中抑制物的总含量最低，其次为SHP和DAP。S. bombicola可以直接利用上述糖化液发酵产SLs，但发酵特性有所不同。SHP和STMEP糖化液更利于酸型槐糖脂(ASL)的积累，相比于化学合成培养基，其产量分别提高了74.27%和92.33%，达到100.45 g/L和110.86 g/L。补加葡萄糖和活性炭脱毒可以进一步提高SLs的产量。对于SHP糖化液，补加葡萄糖及其与活性炭脱毒的联合可将ASL的产量进一步提高至124.49 g/L；对于STMEP糖化液，则可将内酯型槐糖脂(LSL)的产量进一步提高至32.02 g/L，与化学合成培养基的LSL发酵水平相当。因此，小麦秸秆具备发酵产SLs的潜力，且不同预处理方式及发酵方式可用于获得不同类型的SLs，本研究有助于降低SLs的生产成本并拓展其应用领域。
The effects of pretreatment methods of wheat straw on sophorolipids (SLs) fermentation by Starmerella bombicola were investigated, and the fermentation parameters were optimized. Dilute acid pretreatment (DAP), sodium hydroxide pretreatment (SHP) or sulfur trioxide microthermal explosion pretreatment (STMEP) were chosen to pretreat wheat straw to enhance the following enzymatic saccharification. Then, the saccharification liquids were used for SLs fermentation, respectively. Glucose supplement and activated carbon detoxification were used to improve SLs production. The results showed that SHP was the most favorable method for enzymatic saccharification of wheat straw, and the glucose content reached 61.30 g/L, followed by STMEP and DAP, with glucose content of 48.33 g/L and 40.00 g/L, respectively. The total content of inhibitors in STMEP saccharification liquid was the lowest, followed by SHP and DAP. S. bombicola could directly use the above saccharification solution to produce SLs, but the fermentation characteristics were different. Compared to the control chemical synthesis medium, SHP and STMEP saccharification medium were more conducive to acidic sophorolipid (ASL) accumulation, and the yield increased by 74.27% and 92.33% to 100.45 g/L and 110.86 g/L. Glucose addition and activated carbon detoxification could further improve SLs production. For SHP saccharification medium, glucose addition combined with activated carbon detoxification further increased ASL production to 124.49 g/L; For STMEP saccharification medium, lactonic sophorolipid (LSL) production was further increased to 32.02 g/L, which was similar to the LSL fermentation level of chemical synthesis medium. Therefore, wheat straw had potential for SLs production, and different pretreatment methods and fermentation methods can be used to obtain different types of SLs. The present study is benificial to reduce the production cost of SLs and expand its application field.