Department of Environmental Engineering, Da-Yeh University, Changhua, Taiwan.
Bioresour Technol. 2011 Feb;102(4):3966-9. doi: 10.1016/j.biortech.2010.11.066. Epub 2010 Nov 21.
Sequential fermentation for the production of two invaluable biopolymers, levan and poly-ε-lysine (ε-PL), has been successfully developed. It involves fermentation of Bacillus subtilis (natto) Takahashi in sucrose medium to produce levan, separation of levan product from small remaining sugar molecules by ultrafiltration and fermentation of the remnant from levan production by Streptomyces albulus to produce ε-PL. In the process, 50-60 g/L of levan was produced (100% recovery after precipitation by ethanol). The remnant from levan production with glucose adjusted to 30 g/L and with combined use of yeast extract (10 g/L), (NH(4))(2)SO(4) (2g/L) and basal salts was proven to be suitable for ε-PL production. 4.37 g/L of ε-PL accumulation (85% recovery after purification) was reached in 72 h using two-stage fermentation with control of pH. The process of using remnant (waste) from levan fermentation for the second biopolymer (ε-PL) production is unprecedented and the products obtained are environmental-friendly.
已成功开发出一种用于生产两种极具价值的生物聚合物——蔗聚糖和聚-ε-赖氨酸（ε-PL）的连续发酵方法。该方法涉及在蔗糖培养基中发酵纳豆芽孢杆菌（纳豆）以生产蔗聚糖，通过超滤从剩余的小糖分子中分离蔗聚糖产物，并通过白色链霉菌发酵蔗聚糖生产的残余物来生产ε-PL。在此过程中，可生产出 50-60g/L 的蔗聚糖（乙醇沉淀后 100%回收）。将蔗聚糖生产的残余物中的葡萄糖调整至 30g/L，并使用酵母提取物（10g/L）、(NH4)2SO4（2g/L）和基础盐进行组合使用，被证明适合用于ε-PL 的生产。通过 pH 控制的两阶段发酵，可在 72 小时内达到 4.37g/L 的ε-PL 积累（纯化后 85%回收）。使用蔗聚糖发酵的残余物（废物）进行第二种生物聚合物（ε-PL）生产的方法是前所未有的，并且获得的产品是环保的。
