Facile co-deposition of folic acid and polydopamine: Regulation of surface roughness on yeast adhesion in the continuous fermentation

Background

Adhesion is the basis of the cell immobilization, with the surface roughness being a critical factor in promoting the cell initial adhesion and biofilm formation. This study presented a versatile co-deposition approach that combined folic acid (FA) and dopamine (DA) for generating the rough surface.

Methods

Inspired by DA self-polymerization, a rough hierarchical structure incorporated with FA was constructed on the surface of cotton fibers (CF) through π-π interactions and hydrogen bonds (DA+FA-CF). Various modification parameters were investigated to explore the effect of the surface roughness on cell adhesion, biofilm formation, and continuous fermentation of Saccharomyces cerevisiae.

Significant Findings

The optimal FA concentration, modification time and deposition time (0.5 g/L, 6 h and 8 h) yielded the highest surface roughness, which significantly increased the immobilization efficiency from 54.92 % to 74.91 %, and the biomass from 5.95 g/L to 8.70 g/L, respectively. Moreover, DA+FA-CF reduced the fermentation period by 66.67 % and achieved an ethanol yield of 39.67 %, with a peak production of 23.75 g/L in the fifth-batch of continuous fermentation. This strategy offered a facile and biocompatible approach to improving continuous fermentation performance through surface roughness-regulated cell immobilization.