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【目的】从代谢流量分配的角度,探讨Genome shuffling导致链霉菌ε-聚赖氨酸合成量提升的原因。【方法】从葡萄糖耐受型的亲本菌株Streptomyces sp.AS32和ε-聚赖氨酸耐受型的亲本菌株Streptomyces albulus F15出发,进行三轮Genome shuffling,筛选得到ε-聚赖氨酸产量提高的链霉菌株Streptomyces sp.AF3-44,采用通量分析方法构建链霉菌ε-聚赖氨酸合成代谢网络,并对上述3株菌的代谢通量进行比较。【结果】AF3-44的ε-聚赖氨酸摇瓶产量为3.1 g/L,较AS32和F15分别提高了34%和29%。3株菌株中AS32三羧酸循环(TCA)的代谢通量最高;F15磷酸戊糖途径(PPP)代谢通量最高;AF3-44流向赖氨酸合成前体天冬氨酸以及ε-聚赖氨酸的通量最高,TCA和PPP通量位于两亲本菌株的中间水平,其中TCA中流向异柠檬酸的通量分别为AS32和F15的77%和116%,PPP中流向5-磷酸核酮糖的通量分别为AS32和F15的149%和92%。【结论】Genome shuffling导致了代谢流的重新分布,流向前体赖氨酸和ε-聚赖氨酸通量的增加,以及PPP和TCA通量配比的改变是链霉菌ε-聚赖氨酸合成量增加的重要因素。
【Objective】 The purpose of this study was to explore the reasons why Genome shuffling led to the increase of Streptomyces ε-polylysine from the view of metabolic flux distribution. 【Method】 Three rounds of Genome shuffling were performed starting from the glucose tolerant parent strain Streptomyces sp. AS32 and the ε-polylysine-tolerant parent strain Streptomyces albulus F15. The yield of ε-polylysine was increased Streptomyces sp.AF3-44 was used to construct the metabolic network of Streptomyces spp-ε-polylysine, and the metabolic fluxes of these three strains were compared. 【Result】 The yield of ε-polylysine shake flask of AF3-44 was 3.1 g / L, which was 34% and 29% higher than that of AS32 and F15, respectively. The metabolic flux of AS32 tricarboxylic acid cycle (TCA) was the highest among the three strains. The F15 pentose phosphate metabolic pathway (PPP) had the highest metabolic flux. AF3-44 flowed to lysine to synthesize aspartic acid and ε- The flux of TCA and PPP was at the middle level between the two parent strains, and the flux of TCA to isocitrate was 77% and 116% of that of AS32 and F15 respectively. The flux of sugar was 149% and 92% of AS32 and F15, respectively. 【Conclusion】 Genome shuffling resulted in the redistribution of metabolic flux, the increase of the flux of precursor lysine and ε-polylysine, and the change of the ratio of PPP and TCA fluxes were Streptomyces ε-polylysine Synthesis of an important factor in the increase.