Department of Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing 100083, China.
College of Energy and Power Engineering, Inner Mongolia University of Technology, 49 Aimin Road, Xincheng District, Huhhot 010051, China.
Bioresour Technol. 2017 Oct;241:915-921. doi: 10.1016/j.biortech.2017.06.005. Epub 2017 Jun 7.
The feasibility of lactic acid production from Sophora flavescens residues (SFRs) pretreated with sodium hydroxide with the reutilization of the pretreated liquor during fermentation was investigated. After sodium hydroxide pretreatment, 67.5% of the lignin was removed, and hydrolysis efficiency increased from 37.3% to 79.2%. The reutilization of pretreated liquor at 50% loading during open fermentation of unwashed SFR increased lactic acid production by 34.1%. The pretreated liquor acted as pH buffer and resulted in stable pH and high cellulase activity during fermentation. Inhibitors in the pretreated liquor did not affect the growth of lactic acid bacteria but severely inhibited the growth of ethanol-producing yeast. Consequently, lactic acid production increased and ethanol production was zero at 50% loading. Water consumption during pretreatment and fermentation with 50% pretreated liquor was 1.341L per 100g SFR, which was 67.6% lower than that during fermentation with washed SFR.
考察了用氢氧化钠预处理苦豆子残渣（SFR）并在发酵过程中再利用预处理液生产乳酸的可行性。氢氧化钠预处理后，木质素去除率达到 67.5%，水解效率从 37.3%提高到 79.2%。在未洗涤 SFR 的开放式发酵中，以 50%负载量再利用预处理液可使乳酸产量提高 34.1%。预处理液在发酵过程中起到 pH 缓冲剂的作用，使 pH 稳定，纤维素酶活性高。预处理液中的抑制剂不会影响乳酸菌的生长，但会严重抑制乙醇生产酵母的生长。因此，在 50%负载量时，乳酸产量增加，乙醇产量为零。用 50%预处理液进行预处理和发酵的耗水量为每 100g SFR 1.341L，比用洗涤 SFR 进行发酵时降低了 67.6%。
