Cyanobacteria fouling in photobioreactors: current status and future perspectives for prevention

Cyanobacteria biomass sources have the potential to contribute to the replacement of fossil fuels and to the reduction in global warming by sustainable conversion of atmospheric CO₂ into biofuels and high-value chemicals. Cyanobacteria cultivation in photobioreactors (PBRs) results in biofouling on their transparent inner walls, which reduces photosynthetic efficiency and productivity. While cyanobacteria biofouling in PBRs is recognized as a significant operating challenge, this review draws attention to the lack of studies on antifouling strategies for PBRs involving cyanobacteria and discusses several areas related to cyanobacteria fouling mechanisms on PBR materials, which require further investigation. These include an in-depth analysis of conditioning films, the role of pili and EPS in gliding and adhesion, potential revisions to existing theoretical models for predicting adhesion, and material properties that affect cyanobacteria adhesion. We use knowledge from marine, medical, and industrial biofouling management to help identify strategies to combat cyanobacteria fouling in PBRs, and we review the applicability of various bioinspired physical and chemical strategies, as well as genetic engineering approaches to prevent cyanobacteria biofilm formation in PBRs.