Harvesting efficiency is one of the key issues restricting the further commercialization of microalgae. Traditional biofilm studies only tend to focus on enhancing biofilm formation, while neglecting the subsequent harvesting of the biofilm. In this study, a win-win strategy for high-density microalgal cultivation and low-cost harvesting through biofilm cultivation on a pH-responsive, charge-switchable, patterned membrane was investigated using a polyethylenimine (PEI)-crosslinked polyvinylidene fluoride (PVDF) membrane. The patterned membranes were prepared by spray-modified non-solvent induced phase inversion, and the effect of pattern height on biofilm formation and microalgal harvesting was investigated. The PEI-crosslinked PVDF membrane surface was positively charged below pH 8 and negatively charged above pH 9, resulting in a higher attractive energy below pH 8 and a repulsive energy above pH 9 according to the extended Derjaguin, Landau, Verwey, Overbeek model. Patterning of these membranes increased the active area for microalgal attachment, and created a low-shear area in the valleys that prevents early detachment of microalgal cells. Membranes with a higher pattern height resulted in faster biofilm development and increased final biomass accumulation. Low-energy membrane vibration was applied to enhance cell detachment. pH=7 was found to be the optimal pH for enhanced microalgal biofilm formation on PEI-crosslinked patterned membranes, and a switch to pH=10 was best for microalgal harvesting.

收获效率是限制微藻进一步商业化的关键问题之一。传统的生物膜研究仅倾向于集中于增强生物膜的形成，而忽略了随后收获生物膜的情况。在这项研究中，研究了使用聚乙烯亚胺（PEI）交联的聚偏二氟乙烯（PVDF）在pH响应，电荷可切换的有图案的膜上通过生物膜培养进行高密度微藻培养和低成本收获的双赢策略。膜。通过喷雾改性的非溶剂诱导的相转化制备图案化的膜，并研究图案高度对生物膜形成和微藻收获的影响。PEI交联的PVDF膜表面在pH低于8时带正电，在pH高于9时带负电。根据扩展的Derjaguin，Landau，Verwey，Overbeek模型，在pH低于8时会产生较高的吸引力，在pH高于9时会产生排斥性能量。这些膜的图案增加了微藻附着的活性区域，并在山谷中形成了一个低剪切区，可防止微藻细胞的早期脱落。具有较高图案高度的膜导致更快的生物膜形成和增加的最终生物量积累。应用低能膜振动以增强细胞分离。发现pH = 7是增强PEI交联的有图案的膜上微藻生物膜形成的最佳pH，而切换到pH = 10最适合于微藻收获。这些膜的图案增加了微藻附着的活性区域，并在山谷中形成了一个低剪切区，可防止微藻细胞的早期脱落。具有较高图案高度的膜导致更快的生物膜形成和增加的最终生物量积累。应用低能膜振动以增强细胞分离。发现pH = 7是增强PEI交联的有图案的膜上微藻生物膜形成的最佳pH，而切换到pH = 10最适合于微藻收获。这些膜的图案增加了微藻附着的活性区域，并在山谷中形成了一个低剪切区，可防止微藻细胞的早期脱落。具有较高图案高度的膜导致更快的生物膜形成和增加的最终生物量积累。应用低能膜振动以增强细胞分离。发现pH = 7是增强PEI交联的有图案的膜上微藻生物膜形成的最佳pH，而切换到pH = 10最适合于微藻收获。应用低能膜振动以增强细胞分离。发现pH = 7是增强PEI交联的有图案的膜上微藻生物膜形成的最佳pH，而切换到pH = 10最适合于微藻收获。应用低能膜振动以增强细胞分离。发现pH = 7是增强PEI交联的有图案的膜上微藻生物膜形成的最佳pH，而切换到pH = 10最适合于微藻收获。