Zhang Qianqian, Xiong Zhiyue, Sun Lei, Tian Xiwei, Tian Guiwei, Yang Yiming, Li Xu, Wang Yonghong, Chu Ju
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, P.O. box 329, Shanghai, 200237, People's Republic of China.
Wilmar Biotechnology R&D Center Co., Ltd, Shanghai, 200137, China.
Bioresour Bioprocess. 2021 Sep 3;8(1):84. doi: 10.1186/s40643-021-00433-y.
In this study, the effect of biosurfactant sophorolipids (SLs) on Rhizomucor miehei lipase (RML) fermentation by Aspergillus oryzae was investigated. With the exogenous addition of 0.3% (w/v) SLs in the initial medium, the RML activity reached 430.0 U/mL, an increase of 25.0% compared to the control group. Subsequently, the physiological metabolic responses of A. oryzae to the addition of SLs were further explored. The results showed that though SLs had almost no effect on the RML secretion, it would affect the morphology of the cells. During the late phase of the fermentation, the proportion of middle pellets, which was generally considered as an energetic and stable state for enzyme production was increased with the addition of SLs. Simultaneously, the viscosity of fermentation broth was reduced, which facilitated the increase of oxygen transfer, thereby improving the RML production. Finally, it could be found that the addition of SLs significantly increased the contents of precursor amino acids, especially for those rank first and second of the RML composition, and it could promote the synthesis of RML.
在本研究中，考察了生物表面活性剂槐糖脂（SLs）对米曲霉发酵生产米根霉脂肪酶（RML）的影响。在初始培养基中外源添加0.3%（w/v）的SLs时，RML活性达到430.0 U/mL，相较于对照组提高了25.0%。随后，进一步探究了米曲霉对添加SLs的生理代谢响应。结果表明，虽然SLs对RML的分泌几乎没有影响，但会影响细胞形态。在发酵后期，添加SLs使通常被认为是有利于产酶且稳定的中等大小菌球的比例增加。同时，发酵液的黏度降低，这有利于提高氧传递，从而提高RML的产量。最后发现，添加SLs显著增加了前体氨基酸的含量，尤其是在RML组成中排名第一和第二的氨基酸，并且能够促进RML的合成。
