Biofilm-based microalgal cultivation has recently received great attention owing to its low harvesting cost, but the main problem in practicing it is the low rate of attachment on solid carriers. The aim of this research is to introduce novel physical and wet chemical surface engineering methods to provide more favorable polymeric surfaces for microalgal adhesion. PET threads were used as a substrate in the treatments. The surface of the threads was treated with chromic acid, sodium hydroxide and sandpaper. The chemical composition, surface morphology, topography and contact angle of the threads were characterized. The threads were placed in a biofilm-based cylindrical photobioreactor as a bed for attachment. Two freshwater single-cell microalgae, Scenedesmus dimorphus and Chlorella vulgaris, were cultivated in the photobioreactor to assess the attachment rate of the threads. The analysis of SEM and AFM images confirmed the creation of new grooves. The AFM image analysis showed 323%, 184% and 11.5% increase in the surface roughness, while there were 73%, 51%, and 30% rates of reduction in the contact angles for the treatments with acid, sandpaper and base, respectively. Creation of new grooves, increase of the surface roughness and decrease of the contact angle led to an increase in the microalgae attachment rate. The best results were achieved with acid treatment. It led to a remarkable increase in the attachment rate of S. dimorphus. However, the attachment of C. vulgaris cells was not efficient. This research is the first to apply a surface engineering method to increase the microalgal attachment rate in biofilm-based systems. The insight that is provided can be of benefit for further studies in this field.

基于生物膜的微藻培养由于其收获成本低而最近受到了极大的关注，但在实践中的主要问题是在固体载体上的附着率低。本研究的目的是引入新的物理和湿化学表面工程方法，为微藻粘附提供更有利的聚合物表面。PET 线用作处理中的基材。螺纹表面用铬酸、氢氧化钠和砂纸处理。表征了线的化学成分、表面形态、形貌和接触角。将线放置在基于生物膜的圆柱形光生物反应器中作为附着床。两种淡水单细胞微藻，Scenedesmus dimorphus和Chlorella vulgaris, 在光生物反应器中培养以评估线的附着率。SEM 和 AFM 图像的分析证实了新凹槽的产生。AFM 图像分析显示表面粗糙度增加了 323%、184% 和 11.5%，而用酸、砂纸和碱处理的接触角分别降低了 73%、51% 和 30%。新凹槽的产生、表面粗糙度的增加和接触角的减小导致微藻附着率的增加。用酸处理获得了最好的结果。这导致S. dimorphus的附着率显着增加。然而，C. vulgaris的附着细胞效率不高。这项研究首次应用表面工程方法来提高基于生物膜的系统中的微藻附着率。所提供的见解可能有助于该领域的进一步研究。