Ali Memon Kashif, Liu Xiuping, Li Jiaqian, Zhu Xingyu, Sen Biswarup, Wang Guangyi
Center of Marine Environmental Ecology, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, China.
Antioxidants (Basel). 2023 Apr 30;12(5):1034. doi: 10.3390/antiox12051034.
Media supplementation has proven to be an effective technique for improving byproduct yield during microbial fermentation. This study explored the impact of different concentrations of bioactive compounds, namely alpha-tocopherol, mannitol, melatonin, sesamol, ascorbic acid, and biotin, on the sp. TWZ-97 culture. Our investigation revealed that alpha-tocopherol was the most effective compound in reducing the reactive oxygen species (ROS) burden, both directly and indirectly. Adding 0.7 g/L of alpha-tocopherol led to an 18% improvement in biomass, from 6.29 g/L to 7.42 g/L. Moreover, the squalene concentration increased from 129.8 mg/L to 240.2 mg/L, indicating an 85% improvement, while the squalene yield increased by 63.2%, from 19.82 mg/g to 32.4 mg/g. Additionally, our comparative transcriptomics analysis suggested that several genes involved in glycolysis, pentose phosphate pathway, TCA cycle, and MVA pathway were overexpressed following alpha-tocopherol supplementation. The alpha-tocopherol supplementation also lowered ROS levels by binding directly to ROS generated in the fermentation medium and indirectly by stimulating genes that encode antioxidative enzymes, thereby decreasing the ROS burden. Our findings suggest that alpha-tocopherol supplementation can be an effective method for improving squalene production in sp. TWZ-97 culture.
培养基添加已被证明是提高微生物发酵过程中副产物产量的有效技术。本研究探讨了不同浓度的生物活性化合物，即α-生育酚、甘露醇、褪黑素、芝麻酚、抗坏血酸和生物素，对sp. TWZ-97培养物的影响。我们的研究表明，α-生育酚是直接和间接减轻活性氧（ROS）负担最有效的化合物。添加0.7 g/L的α-生育酚使生物量提高了18%，从6.29 g/L提高到7.42 g/L。此外，角鲨烯浓度从129.8 mg/L增加到240.2 mg/L，提高了85%，而角鲨烯产量从19.82 mg/g增加到32.4 mg/g，提高了63.2%。此外，我们的比较转录组学分析表明，添加α-生育酚后，参与糖酵解、磷酸戊糖途径、三羧酸循环和甲羟戊酸途径的几个基因被上调。添加α-生育酚还通过直接结合发酵培养基中产生的ROS以及间接刺激编码抗氧化酶的基因来降低ROS水平，从而减轻ROS负担。我们的研究结果表明，添加α-生育酚可能是提高sp. TWZ-97培养物中角鲨烯产量的有效方法。
