Nastouli Alexandra, Tsirigka Asimina, Harasek Michael, Karabelas Anastasios J, Patsios Sotiris I
Laboratory of Natural Resources and Renewable Energies, Chemical Process & Energy Resources Institute (CPERI), Centre for Research and Technology-Hellas (CERTH), GR 57001 Thessaloniki, Greece.
Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, AU 1040 Vienna, Austria.
Membranes (Basel). 2022 Jul 22;12(8):725. doi: 10.3390/membranes12080725.
Membrane processes can be integrated with fermentation for the selective separation of the products from the fermentation broth. Sterilization with saturated steam under pressure is the most widely used method; however, data concerning heat sterilization applicability to polymeric ultrafiltration (UF) membranes are scarcely available. In this study, the effect of the sterilization process on the filtration performance of a commercial polyvinylidene difluoride (PVDF) hollow fiber UF membrane was evaluated. Membrane modules were constructed and sterilized several times in an autoclave. Pure water flux tests were performed, to assess the effect of heat sterilization on the membrane's pure water permeance. Dextran rejection tests were performed for the characterization of membrane typical pore size and its fouling propensity. Filtration performance was also assessed by conducting filtration tests with real fermentation broth. After repeated sterilization cycles, pure water permeance remained quite constant, varying between approx. 830 and 990 L·m·h·bar, while the molecular weight cut-off (MWCO) was estimated to be in the range of 31.5-98.0 kDa. Regarding fouling behavior, the trans-membrane pressure increase rate was stable and quite low (between 0.5 and 7.0 mbar/min). The results suggest that commercial PVDF UF membranes are a viable alternative to high-cost ceramic UF membranes for fermentation processes that require heat sterilization.
膜分离过程可以与发酵相结合，用于从发酵液中选择性分离产物。压力饱和蒸汽灭菌是最广泛使用的方法；然而，关于热灭菌对聚合物超滤（UF）膜适用性的数据却很少。在本研究中，评估了灭菌过程对商用聚偏氟乙烯（PVDF）中空纤维超滤膜过滤性能的影响。构建膜组件并在高压釜中进行多次灭菌。进行纯水通量测试，以评估热灭菌对膜纯水透过率的影响。进行葡聚糖截留测试，以表征膜的典型孔径及其污染倾向。还通过用实际发酵液进行过滤测试来评估过滤性能。经过多次灭菌循环后，纯水透过率保持相当稳定，约在830至990 L·m·h·bar之间变化，而截留分子量（MWCO）估计在31.5 - 98.0 kDa范围内。关于污染行为，跨膜压力增加率稳定且相当低（在0.5至7.0 mbar/min之间）。结果表明，对于需要热灭菌的发酵过程，商用PVDF超滤膜是高成本陶瓷超滤膜的可行替代品。
