玉米浆是玉米湿磨工业的主要副产品,在工业发酵中被广泛用作经济有效的营养源。然而,玉米浆影响发酵性能的潜在机制仍不清楚。该研究发现添加不同浓度的玉米浆可以促进谷氨酸棒杆菌(Corynebacterium glutamicum)发酵生产L-高丝氨酸。为探究添加玉米浆对L-高丝氨酸合成途径相关的基因与代谢通路的影响,利用转录组学分析并挖掘其潜在的关键基因,最终通过定量逆转录聚合酶链反应进行验证。结果表明,编码醛脱氢酶Ald的cg3096在玉米浆高效促进L-高丝氨酸发酵生产中发挥着主要作用,这可能部分归因于细胞内NADPH供应水平的提高。此外,过表达cg3096可以显著提高底物转运(amt、cg0922、urtABC)和利用基因(cg0535-cg0536)的表达水平。综上所述,该研究结果揭示了cg3096在L-高丝氨酸高水平生产中的基本功能和潜在机制,为玉米浆在发酵过程中高效利用提供了新的视角。
Corn steep liquor (CSL) is a major by-product of the corn wet milling industry, widely employed as a cost-effective nutrient source in industrial fermentations.However, the underlying mechanisms by which CSL affected the fermentation performance remain largely unclear.This study observed that the addition of CSL at varying concentrations facilitated the fermentative production of L-homoserine in Corynebacterium glutamicum.To explore the effects of adding CSL on genes and metabolic pathways related to the L-homoserine synthesis pathway, transcriptome analysis was used to explore its potential novel genes and finally verified by quantitative reverse transcription polymerase chain reaction.Results revealed that the cg3096, coding for an aldehyde dehydrogenase Ald, was essential for effectively promoting the fermentation of CSL to produce L-homoserine.This efficient production of L-homoserine may be partially attributed to the increased levels of intracellular NADPH supply.Further investigation implied that overexpression of cg3096 also resulted in increased expression levels of some substrate transport (amt, cg0922, urtABC) and utilization genes (cg0535-cg0536).Collectively, the findings revealed the essential function and possible mechanism of cg3096 in achieving a high level of L-homoserine production, providing new perspectives on the effectiveness of CSL in fermentation.
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