一株新型耐盐芽孢杆菌 F29 增强聚-γ-谷氨酸生产的研究
Enhanced Poly-γ-Glutamic Acid Production by a Newly Isolated Bacillus halotolerans F29.
机构信息
Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, People's Republic of China.
Lab of Biorefinery, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, 201210, People's Republic of China.
出版信息
J Microbiol. 2024 Aug;62(8):695-707. doi: 10.1007/s12275-024-00153-w. Epub 2024 Aug 20.
Poly-γ-glutamic acid (γ-PGA) is a promising biopolymer for various applications. In this study, we isolated a novel γ-PGA-producing strain, Bacillus halotolerans F29. The one-factor-at-a-time method was used to investigate the influence of carbon sources, nitrogen sources, and culture parameters on γ-PGA production. The optimal carbon and nitrogen sources were sucrose and (NH)SO, respectively. The optimal culture conditions for γ-PGA production were determined to be 37 °C and a pH of 5.5. Response surface methodology was used to determine the optimum medium components: 77.6 g/L sucrose, 43.0 g/L monosodium glutamate, and 2.2 g/L KHPO. The γ-PGA titer increased significantly from 8.5 ± 0.3 g/L to 20.7 ± 0.7 g/L when strain F29 was cultivated in the optimized medium. Furthermore, the γ-PGA titer reached 50.9 ± 1.5 g/L with a productivity of 1.33 g/L/h and a yield of 2.23 g of γ-PGA/g of L-glutamic acid with the optimized medium in fed-batch fermentation. The maximum γ-PGA titer reached 45.3 ± 1.1 g/L, with a productivity of 1.06 g/L/h when molasses was used as a carbon source. It should be noted that the γ-PGA yield in this study was the highest of all reported studies, indicating great potential for the industrial production of γ-PGA.
聚-γ-谷氨酸(γ-PGA)是一种很有前途的生物聚合物,可应用于各种领域。在本研究中,我们分离到一株产γ-PGA 的新菌株,即耐盐芽孢杆菌 F29。采用单因素法考察了碳源、氮源和培养条件对γ-PGA 生产的影响。结果表明,最佳碳源和氮源分别为蔗糖和(NH4)2SO4。最佳产γ-PGA 条件为:37℃、pH5.5。采用响应面法优化培养基成分,确定的最佳培养基组成为:77.6 g/L 蔗糖、43.0 g/L 谷氨酸钠和 2.2 g/L KH2PO4。在优化后的培养基中,F29 菌株的γ-PGA 产量从 8.5±0.3 g/L 显著提高到 20.7±0.7 g/L。进一步在补料分批发酵中,当用优化后的培养基培养时,γ-PGA 产量达到 50.9±1.5 g/L,生产强度为 1.33 g/L/h,γ-PGA 对 L-谷氨酸的得率为 2.23 g/g。当以糖蜜为碳源时,γ-PGA 的最大产量达到 45.3±1.1 g/L,生产强度为 1.06 g/L/h。需要注意的是,本研究中的 γ-PGA 产量在所有已报道的研究中是最高的,这表明 γ-PGA 的工业化生产具有巨大潜力。