Abstract Poly-γ-glutamic acid (γ-PGA) is a retaining agent; it has applications in the food, medicine, agriculture, cosmetics and wastewater treatment industries. Most of the γ-PGA producing strains belong to the genus Bacillus. This study reports on a novel γ-PGA producing species. Bacillus siamensis SB1001 was screened and isolated from organically cultivated soybeans exhibiting a high γ-PGA producing ability. The fermentation medium and culture parameters for γ-PGA production by Bacillus siamensis SB1001 were optimized by statistical methods. The sucrose, l -glutamic acid and dipotassium phosphate in the medium were shown to be the significant factors of the γ-PGA production, and the optimum medium obtained consisted of the following: 106.86 g/L sucrose, 69.84 g/L l -glutamic acid and 2.39 g/L dipotassium phosphate. Using the optimized medium, 25.22 g/L γ-PGA were produced with a productivity of 1.05 g/L/h. The γ-PGA obtained had a molecular weight of 7.9 × 105 Da and a polydispersity index of 2.34, and the ratio of d -/L-glutamic acid was 89.71%:10.29%. To the best of our knowledge, this is the first report of γ-PGA production by B. siamensis strain. B. siamensis SB1001 has great potential as an industrial γ-PGA producer.

中文翻译：

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一种新分离的暹罗芽孢杆菌SB1001用于聚γ-谷氨酸的大规模生产

摘要 聚-γ-谷氨酸（γ-PGA）是一种保留剂；它在食品、医药、农业、化妆品和废水处理行业都有应用。大多数产生γ-PGA的菌株属于芽孢杆菌属。本研究报告了一种新的 γ-PGA 生产物种。暹罗芽孢杆菌 SB1001 是从有机栽培大豆中筛选和分离的，具有高 γ-PGA 生产能力。通过统计方法优化了暹罗芽孢杆菌SB1001生产γ-PGA的发酵培养基和培养参数。培养基中蔗糖、L-谷氨酸和磷酸二钾是γ-PGA产量的重要因素，得到的最佳培养基如下：蔗糖106.86 g/L，L-谷氨酸69.84 g/L酸和 2.39 g/L 磷酸二钾。使用优化的介质，以 1.05 g/L/h 的生产率生产了 25.22 g/L γ-PGA。得到的γ-PGA分子量为7.9×105 Da，多分散指数为2.34，d-/L-谷氨酸比为89.71%：10.29%。据我们所知，这是 B. siamensis 菌株生产 γ-PGA 的第一份报告。B. siamensis SB1001 作为工业 γ-PGA 生产商具有巨大潜力。