Whole-cell systems offer many benefits for biochemical production, such as relatively easy enzyme control and higher tolerance toward harsh environments, than purified enzymes. These systems can be applied to many bioconversion reactions, but they sometimes require cofactor regeneration units to support reactions at high substrate concentrations. Here, we examined l-glutamate oxidase (GOX) from Streptomyces sp. X119-6, which produces α-ketoglutarate (α-KG) from l-glutamate, and catalase (KatE) from Escherichia coli, which removes hydrogen peroxide generated by GOX. After optimizing the expression vector, pH, strains, culture conditions, and isopropyl β-d-1-thiogalactopyranoside concentration, we compared their efficiency to that of a previously reported GOX from Streptomyces mobaraensis. Our results indicated that GOX from Streptomyces sp. X119-6 and KatE increased α-KG production by 2.76-fold. This GOX required high levels of α-KG as an amino donor to convert 5-aminovaleric acid to glutaric acid. Performing the reaction at pH 8 enabled us to avoid the exogenous addition of catalase, but severe substrate inhibition was observed, resulting in the production of 287 mM glutaric acid. This α-KG regeneration system has potential for improving production in various aminotransferase systems.

与纯化酶相比，全细胞系统为生化生产提供了许多好处，例如相对容易的酶控制和对恶劣环境的更高耐受性。这些系统可以应用于许多生物转化反应，但它们有时需要辅因子再生单元来支持高底物浓度下的反应。在这里，我们检查了来自链霉菌属的l-谷氨酸氧化酶 (GOX) 。X119-6，从l-谷氨酸产生α-酮戊二酸 ( α- KG) ，从大肠杆菌中产生过氧化氢酶 (KatE) ，去除 GOX 产生的过氧化氢。优化表达载体，pH值，菌株，培养条件，和异丙基后β -d -1-硫代吡喃半乳糖苷浓度，我们将它们的效率与先前报道的来自Streptomyces mobaraensis 的GOX 的效率进行了比较。我们的结果表明来自链霉菌属的GOX 。X119-6 和 KatE 将α -KG 产量提高了 2.76 倍。该 GOX 需要高水平的α- KG 作为氨基供体才能将 5-氨基戊酸转化为戊二酸。在 pH 8 下进行反应使我们能够避免外源性添加过氧化氢酶，但观察到严重的底物抑制，导致产生 287 mM 戊二酸。这种α- KG 再生系统具有提高各种转氨酶系统产量的潜力。