The biorefinery industry has processed lignocellulosic biomass for the production of bio-based products, which accompanies with the generation of proteins in waste streams. Glutamate (Glu) is a non-essential amino acid rich in various sources of protein waste. To explore the usefulness of Glu, Glu metabolism in Escherichia coli was deciphered by the genetic approach. Key pathways involving Glu catabolism were identified, and the analysis of end product profiles revealed the flux distribution in central metabolism. Using ethanol as an example, the rate-limiting reaction catalyzed by aspA was manipulated to adjust the cataplerostic flux in the tricarboxylic acid cycle. This in turn redistributes the flux between glycolysis and gluconeogenesis. Consequently, it improves the ethanol production which reaches 85% of the theoretical yield. Overall, the result of this study indicates that Glu is a new renewable source with a potential application in biorefinery and biotechnology.

生物炼油业已经加工了木质纤维素生物质，以生产生物基产品，并伴随着废物流中蛋白质的产生。谷氨酸（Glu）是一种非必需氨基酸，富含各种蛋白质废物来源。为了探索Glu的有用性，通过遗传方法破译了大肠杆菌中的Glu代谢。确定了涉及Glu分解代谢的关键途径，对最终产物谱的分析揭示了中枢代谢中的通量分布。以乙醇为例，aspA催化的限速反应调节三羧酸循环中的催化过氧化通量。反过来，这又重新分配了糖酵解和糖异生之间的通量。因此，它可以提高乙醇产量，达到理论收率的85％。总体而言，这项研究的结果表明，Glu是一种新的可再生资源，在生物精炼和生物技术中具有潜在的应用。