Accelerated adhesion of immobilized Saccharomyces cerevisiae on electrophilic interface modified by co-deposition of dopamine and chitosan.

The development of immobilized biofilm systems through interface engineering represents an effective strategy for bioprocess intensification. Developing functional biofilm carrier interfaces that combine facile fabrication and cost-effectiveness remains a critical challenge in translating immobilized biofilm catalytic systems to industrial applications. In this study, we propose modulating the surface charge microenvironment of the carrier through the encoding of dopamine and chitosan systems to meet the requirements for biofilm system formation. During batch fermentation (50 mL fermentation broth system) using Saccharomyces cerevisiae under a 60 g/L glucose substrate condition, the electrophilic interface carrier exhibited stable biofilm formation, with a maximum density of 66.9 mg/g carrier (33.1 % higher than unmodified carriers) and an immobilization efficiency of 73.1 %. When the glucose concentration was increased to 200 g/L and Saccharomyces cerevisiae was replaced with industrial yeast used in industrial production (200 mL fermentation broth system), the electrophilic interface carrier immobilized fermentation system achieved an ethanol titer of 109.1 g/L, representing 116.2 % of the conventional free-cell fermentation (93.9 g/L), while increasing ethanol productivity to 55.6 %. The immobilized fermentation system exhibited a substrate consumption rate of 6.5 g/L/h, representing a 16.4 % enhancement over conventional free-cell fermentation. The simplicity of carrier fabrication, coupled with its demonstrated performance, establishes a practical foundation for the development of continuous immobilized biofilm systems, offering significant potential for process intensification and industrial-scale implementation.