Pongtharangku Thunyarat, Demirci Ali
Department of Agricultural and Biological Engineering, Pennsylvania State University, University Park, PA, 16802, USA.
Appl Microbiol Biotechnol. 2007 Mar;74(3):555-62. doi: 10.1007/s00253-006-0697-7. Epub 2006 Nov 17.
An online removal of nisin by silicic acid coupled with a micro-filter module was proposed as an alternative to reduce detrimental effects caused by adsorption of nisin onto producer, enzymatic degradation by protease, and product inhibition during fermentation. In this study, silicic acid was successfully used to recover nisin from the fermentation broth of Lactococcus lactis subsp. lactis NIZO 22186. The effect of pH (at 6.8 and 3.0) during adsorption process and several eluents (deionized water, 20% ethanol, 1 M NaCl, and 1 M NaCl + 20% ethanol) for desorption were evaluated in a small batch scale. Higher nisin adsorption onto silicic acid was achieved when the adsorption was carried out at pH 6.8 (67% adsorption) than at pH 3.0 (54% adsorption). The maximum recovery was achieved (47% of nisin was harvested) when the adsorption was carried out at pH 6.8 and 1 M NaCl + 20% ethanol was used as an eluent for desorption. Most importantly, nisin production was significantly enhanced (7,445 IU/ml) when compared with the batch fermentation without the online recovery (1,897 IU/ml). This may possibly be attributed to preventing the loss of nisin due the detrimental effects and a higher biomass density achieved during online recovery process, which stimulated production of nisin during fermentation.
提出了一种通过硅酸与微滤模块在线去除乳链菌肽的方法，作为减少乳链菌肽吸附到生产菌上、蛋白酶酶解以及发酵过程中产物抑制所造成的有害影响的替代方法。在本研究中，成功利用硅酸从乳酸乳球菌乳酸亚种NIZO 22186的发酵液中回收乳链菌肽。在小批量规模下评估了吸附过程中pH值（6.8和3.0）以及几种洗脱剂（去离子水、20%乙醇、1 M NaCl和1 M NaCl + 20%乙醇）对解吸的影响。在pH 6.8下进行吸附时，硅酸对乳链菌肽的吸附量更高（67%的吸附率），高于pH 3.0时的吸附量（54%的吸附率）。当在pH 6.8下进行吸附并使用1 M NaCl + 20%乙醇作为洗脱剂进行解吸时，实现了最大回收率（收获了47%的乳链菌肽）。最重要的是，与没有在线回收的分批发酵（1,897 IU/ml）相比，乳链菌肽产量显著提高（7,445 IU/ml）。这可能归因于防止了由于有害影响导致的乳链菌肽损失，以及在线回收过程中实现了更高的生物量密度，从而刺激了发酵过程中乳链菌肽的产生。
