Ege University, Faculty of Engineering, Department of Food Engineering, 35100 Bornova, İzmir, Turkey.
Carbohydr Polym. 2014 Jan;99:454-61. doi: 10.1016/j.carbpol.2013.08.031. Epub 2013 Aug 23.
Levan production in batch and continuous fermentation systems by Zymomonas mobilis B-14023 was investigated. The culture medium used in both of the fermentation systems contained sucrose and various organic nitrogen sources. Maximum concentration of levan was produced with yeast extract among the nitrogen sources tested. Response surface methodology was used to investigate the effects of three factors on the concentration of levan in batch cultures of Z. mobilis. Maximum levan concentration was 40.2 g/L and this concentration was reached at the optimum levels of process variables, which were 299.1 g/L initial substrate concentration, 42.3 h incubation time, and initial pH 6.0. Continuous fermentation experiments were done in packed bed bioreactor using Ca-alginate immobilized Z. mobilis cells. The highest levan concentration (31.8 ± 0.21 g/L) was obtained at a dilution rate of 0.14 h(-1) while maximum volumetric productivity (6.556 g/(Lh)) was obtained at a dilution rate of 0.22 h(-1). Increasing the dilution rate resulted in decreased levan and increased residual sugar concentrations.
通过 Zymomonas mobilis B-14023 进行分批和连续发酵系统中的莱鲍迪苷生产的研究。两种发酵系统中使用的培养基均含有蔗糖和各种有机氮源。在测试的氮源中，酵母提取物产生的莱鲍迪苷浓度最高。响应面法用于研究三种因素对 Z. mobilis 分批培养中莱鲍迪苷浓度的影响。最大莱鲍迪苷浓度为 40.2 g/L，这一浓度是在过程变量的最佳水平下达到的，初始底物浓度为 299.1 g/L，孵育时间为 42.3 h，初始 pH 值为 6.0。使用 Ca-海藻酸钠固定化 Z. mobilis 细胞在填充床生物反应器中进行连续发酵实验。在稀释率为 0.14 h(-1)时，获得了最高的莱鲍迪苷浓度（31.8 ± 0.21 g/L），而在稀释率为 0.22 h(-1)时，获得了最高的比体积生产率（6.556 g/(Lh)）。增加稀释率会导致莱鲍迪苷和残留糖浓度降低。
