In this study, Rhodococcus pyridinivorans cells containing hyperactive acyltransferase was immobilized on various macromolecules based-polymeric matrices and used to improve acetohydroxamic acid production. The calcium-alginate-based matrix retained the maximum residual activity up to 97.8% as compared to free cells (576 U/mg of dry cell weight). After immobilization, cells exhibited a significant improvement in their tolerance towards pH, temperature, and metal ions as potent enzyme inhibitors. Immobilized cells showed 25.5-fold higher thermal stability at 60 °C to control (free cells). Compared to free cells, immobilized cells exhibited a high bioconversion of acetamide and hydroxylamine-HCl to acetohydroxamic acid up to 96% molar conversion. Repeated bench-scale production at 3-L culture, immobilized cells showed 9.5-fold higher residual conversion as compared to control (100%), after five cycles of reuses. The product characterization achieved high purity (97%) of acetohydroxamic acid. This finding showed high feasibility to achieve efficient conversion that can be scaled up to the industrial level for biotechnological application.

Graphical Abstract

中文翻译：

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生物工艺放大生产乙酰异羟肟酸的高活性酰基转移酶的固定化吡啶红球菌

在本研究中，嗜吡啶红球菌含有高活性酰基转移酶的细胞被固定在各种基于大分子的聚合物基质上，用于提高乙酰异羟肟酸的产量。与游离细胞（576 U/mg 干细胞重量）相比，基于藻酸钙的基质保留了高达 97.8% 的最大残留活性。固定化后，细胞对 pH、温度和金属离子作为强效酶抑制剂的耐受性显着提高。与对照（游离细胞）相比，固定化细胞在 60 °C 下的热稳定性提高了 25.5 倍。与游离细胞相比，固定化细胞表现出乙酰胺和羟胺-HCl 向乙酰异羟肟酸的高生物转化率，摩尔转化率高达 96%。在 3-L 培养中重复进行小规模生产，固定化细胞的残留转化率比对照 (100%) 高 9.5 倍，经过五次重复使用。产品表征实现了高纯度 (97%) 的乙酰异羟肟酸。这一发现显示了实现有效转化的高度可行性，该转化可以扩大到生物技术应用的工业水平。

图形概要