Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology & Business University (BTBU), Beijing, 100048, People's Republic of China.
College of Life Science, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.
Microb Cell Fact. 2022 Jul 16;21(1):140. doi: 10.1186/s12934-022-01867-5.
Poly-γ-glutamic acid (γ-PGA) is a biopolymer and has various applications based on its biocompatibility, non-toxicity, and edibility. Low-molecular-weight (Mw)-γ-PGA has promising applications in agriculture and pharmaceuticals. It is traditionally produced by enzymatic hydrolysis. Cost-effective bioproduction of low-Mw-γ-PGA is essential for commercial application of γ-PGA.
Bacillus subtilis 242 is a newly isolated low-Mw-γ-PGA-producing strain. To develop cost-effective production of γ-PGA using this newly isolated strain, cane molasses and corn steep liquor were used to produce γ-PGA. The concentration of cane molasses was optimized and 100 g/L cane molasses resulted in high γ-PGA production. The effects of yeast extract and corn steep liquor on γ-PGA yield were investigated. High concentration of γ-PGA was obtained in the medium with corn steep liquor. A concentration of 32.14 g/L γ-PGA was achieved in fed-batch fermentation, with a productivity of 0.67 g/L/h and a percentage yield (g/g) of 106.39%. The Mw of γ-PGA was 27.99 kDa.
This study demonstrated the potential application of B. subtilis 242 for cost-effective production of low-Mw-γ-PGA from cane molasses.
聚-γ-谷氨酸（γ-PGA）是一种生物聚合物，具有生物相容性、无毒和可食用等特点，因此具有广泛的应用。低分子量（Mw）-γ-PGA 在农业和制药领域具有广阔的应用前景。传统上，它是通过酶解生产的。低分子量 γ-PGA 的经济高效生产对于 γ-PGA 的商业应用至关重要。
枯草芽孢杆菌 242 是一种新分离的低分子量 γ-PGA 生产菌株。为了利用这种新分离的菌株进行经济高效的 γ-PGA 生产，使用甘蔗糖蜜和玉米浆来生产 γ-PGA。优化了甘蔗糖蜜的浓度，结果表明 100 g/L 的甘蔗糖蜜可实现高 γ-PGA 产量。考察了酵母提取物和玉米浆对 γ-PGA 产量的影响。在含有玉米浆的培养基中可获得高浓度的 γ-PGA。在分批补料发酵中，γ-PGA 的浓度达到 32.14 g/L，生产速率为 0.67 g/L/h，产率（g/g）为 106.39%。γ-PGA 的 Mw 为 27.99 kDa。
本研究表明枯草芽孢杆菌 242 可用于从甘蔗糖蜜中经济高效地生产低分子量 γ-PGA。
