Physiological analysis of the improved ε-polylysine production induced by reactive oxygen species
Physiological analysis of the improved ε-polylysine production induced by reactive oxygen species
复制标题
活性氧诱导提高 β-聚赖氨酸产量的生理分析
DOI：
10.1007/s00253-022-12343-w
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发表时间：
2022-12-31
影响因子：
5
通讯作者：
Zeng，Xin
中科院分区：
文献类型：
--
作者：
Yue，Chaoping;Su，Zhiwei;Zeng，Xin
ε-聚赖氨酸（ε-polylysine，ε-PL）是链霉菌在酸性和好氧条件下产生的产物，其产生不可避免地导致活性氧（reactive oxygen species，ROS）的快速产生。结果在本研究中，我们发现适当剂量的细胞内ROS（约3.3 μ molH 2 O2/gDCW）可以诱导一种生理修饰，促进ε-PL的产生（1.2 ~ 1.5g/L）。结果表明，该菌的菌落和菌丝球较大，菌丝活力强、聚集性好、健壮，具有较强的活性氧解毒能力。生理研究表明，适当剂量的活性氧在转录和酶水平上激活了磷酸戊糖途径的代谢，有利于生物量的积累。赖氨酸的生物合成也在转录调控过表达、关键基因的转录和酶活性增加、TCA循环中代谢产物的更大池、补充途径和二氨基庚二酸途径方面得到促进。此外，通过TCA循环的活化代谢、更大的NADH池和更高的电子传递系统活性来确保能量供应。HrdD和pls基因转录水平的提高进一步促进了ε-PL的生物合成。意义这些结果表明，适当剂量的细胞内活性氧可以作为一种诱导信号激活ε-PL的生物合成，这为进一步调控细胞内活性氧的浓度以维持ε-PL的生物合成奠定了基础，具有重要的理论和实际意义。适当剂量的活性氧能提高菌丝体的活力和抗氧化能力。ROS增加赖氨酸合成代谢、能量供应和pls表达。
IntroductionEpsilon-poly-L-lysine (ε-PL) is produced byStreptomycesspecies in acidic and aerobic conditions, which inevitably induces rapid generation of reactive oxygen species (ROS). The devastating effects of ROS on biomolecules and cell vitality have been well-studied, while the positive effects of ROS are rarely reported.ResultsIn this study, we found that a proper dose of intracellular ROS (about 3.3 μmol H2O2/g DCW) could induce a physiological modification to promote the ε-PL production (from 1.2 to 1.5 g/L). It resulted in larger sizes of colony and mycelial pellets as well as vibrant, aggregated, and more robust mycelia, which were of high capability of ROS detoxication. Physiological studies showed that appropriate doses of ROS activated the metabolism of the pentose phosphate pathway at both transcriptional and enzymatic levels, which was beneficial for biomass accumulation. The biosynthesis of lysine was also promoted in terms of transcriptional regulatory overexpression, increased transcription and enzymatic activity of key genes, larger pools of metabolites in the TCA cycle, replenishment pathway, and diaminoheptanedioic acid pathway. In addition, energy provision was ensured by activated metabolism of the TCA cycle, a larger pool of NADH, and higher activity of the electron transport system. Increased transcription ofHrdDandplsfurther accelerated the ε-PL biosynthesis.SignificanceThese results indicated that ROS at proper intracellular dose could act as an inducing signal to activate the ε-PL biosynthesis, which laid a foundation for further process regulation to maintain optimal ROS dose in industrial ε-PL production and was of theoretical and practical significance.Key points•A proper dose of intracellular ROS positively influences the ε-PL production.•Proper dose of ROS enhanced the mycelial activity and antioxidative capability.•ROS increased lysine synthesis metabolism, energy provision and pls expression.Graphical Abstract