Convenient Screening of Antifouling Agents for Direct Recovery of Bioproducts Employing a Fast Microplate Assay

Abstract Major limitations in direct recovery of bioproducts from unclarified feedstock are predominantly associated with the presence of suspended whole and lysed biomass in processing systems. Most commonly, biomass interaction with adsorbent beads, synthetic membranes, and other processes surfaces causes fouling. This phenomenon is usually detrimental to bioprocess performance. This study focused on the development of a simple, easy to implement, economical and robust technique to evaluate biomass deposition and screening for chemical agents able to prevent such phenomenon. The results were confirmed by linking biomass deposition with surface energetics according to the extended Derjaguin, Landau, Verwey and Overbeek (xDLVO) theory. Assay development involved the modification of the inside surface of microwell polystyrene plates with diethyl-aminoethyl (DEAE) functional groups. The resulting microplate surface mimics commercial chromatographic anion-exchangers matrices that are prone to biomass fouling. Two biomass types, Saccharomyces cerevisiae and Chinese hamster ovary (S. cerevisiae and CHO, respectively) cells and twenty-five polyelectrolytes or amphiphilic compounds were employed. Results showed that DEAE-modified surface had the highest cell deposition while agent-coated wells showed varying degrees. Direct experimental observations and calculations performed based on xDLVO approach indicated that polyacrylic acid, polymethacrylic acid, and poly(vinyl sulfate) could prevent CHO cells and yeast deposition. On the other hand, polysulphonic acid and poly(sodium 4-styrenesulfonate) were only effective to prevent yeast deposition. Microscopic visualization of polymer-coated beads in the presence of biomass confirmed the mentioned results.