Marine College, Shandong University, Weihai, 264209, Shandong, China.
Bioprocess Biosyst Eng. 2020 Oct;43(10):1813-1821. doi: 10.1007/s00449-020-02372-y. Epub 2020 May 12.
Addition of exogenous astaxanthin for improving ε-poly-L-lysine (ε-PL) production in Streptomyces griseofuscus was investigated in this study. By this unique strategy, the ε-PL production in shaker-flask fermentation was 2.48 g/L, which was 67.5% higher than the control at the addition dosage of 1.0 g/L, owing to the oxidation resistance of astaxanthin. In fed-batch fermentation, the ε-PL production reached 36.1 g/L, a 36.3% increase compared to the control. Intracellular response for oxidation in S. griseofuscus such as ROS generation and lipid peroxidation was reduced by astaxanthin addition. Illumina RNA deep sequencing (RNA-seq) technology further revealed that S. griseofuscus with astaxanthin addition showed down-regulated transcriptions of genes involved in oxidative stress. This research proved that the beneficial effect of astaxanthin addition was far better than glutathione (GSH) owing to the stronger antioxidant capacity, and provided a novel approach to regulate ε-PL synthesis.
本研究探讨了添加外源虾青素对提高灰色链霉菌生产 ε-聚赖氨酸（ε-PL）的影响。通过这种独特的策略，在摇瓶发酵中 ε-PL 的产量达到 2.48 g/L，比对照组添加 1.0 g/L 时提高了 67.5%，这归因于虾青素的抗氧化能力。在分批补料发酵中，ε-PL 的产量达到 36.1 g/L，与对照组相比提高了 36.3%。虾青素的添加降低了灰色链霉菌细胞内的氧化反应，如 ROS 的产生和脂质过氧化。Illumina RNA 深度测序（RNA-seq）技术进一步表明，添加虾青素的灰色链霉菌中与氧化应激相关的基因转录水平下调。本研究证明，虾青素的添加效果远远优于谷胱甘肽（GSH），因为虾青素具有更强的抗氧化能力，为调节 ε-PL 合成提供了一种新方法。
