College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, People's Republic of China.
World J Microbiol Biotechnol. 2012 Jan;28(1):91-7. doi: 10.1007/s11274-011-0795-2. Epub 2011 Jun 2.
A bioflocculant with high flocculating activity, LC13-SF, produced by strain LC13(T) which was in a viable but nonculturable (VBNC) state, and which was woken up by Rpf (resuscitation promoting factor), was systematically investigated with regard to its fermentation conditions and flocculating activity. The key parameters influencing the bioflocculant LC13-SF were investigated through measuring the optical density at 660 (OD(660)) of the fermentation liquid and the optical density at 550 (OD(550)) of the centrifugal supernatant. The flocculating efficiency and the Zeta potentials were chosen as the response variables for the study of the flocculating activity. The results showed that the optimal conditions for bioflocculant LC13-SF production were a fermentation time of 72 h, an initial pH of 7.0, a fermentation temperature of 30°C and a shaking speed of 150 r/min. The optimized flocculating process was as follows: a final volume percentage of bioflocculant LC13-SF and 0.5% (w/w) CaCl(2) were 1.5 and 5%, respectively in a 4 g/L Kaolin suspension, and the system pH was adjusted to 8.0. Under these conditions, the flocculating efficiency and the absolute value of the Zeta potential reached 94.83% and 4.37, respectively.
一株产具有高絮凝活性生物絮凝剂 LC13-SF 的 LC13(T) 菌，处于存活但非可培养（VBNC）状态，由 Rpf（复苏促进因子）唤醒，对其发酵条件和絮凝活性进行了系统研究。通过测量发酵液的 660nm 吸光度（OD（660））和离心上清液的 550nm 吸光度（OD（550）），确定了影响生物絮凝剂 LC13-SF 的关键参数。絮凝效率和 Zeta 电位被选为研究絮凝活性的响应变量。结果表明，生物絮凝剂 LC13-SF 生产的最佳条件为发酵时间 72h、初始 pH 值 7.0、发酵温度 30°C 和摇床转速 150r/min。优化的絮凝过程如下：在 4g/L 高岭土悬浮液中，生物絮凝剂 LC13-SF 的最终体积百分比为 1.5%（w/w），CaCl2 为 0.5%，系统 pH 值调至 8.0。在此条件下，絮凝效率和 Zeta 电位的绝对值分别达到 94.83%和 4.37。
