Comparative fermentation performance of biofilm and planktonic Saccharomyces cerevisiae under standard and high-carbon media.

Biofilms are structured microbial communities with wide-ranging industrial applications. In Saccharomyces cerevisiae, biofilm formation can influence fermentation, improve microbial stability, and enhance production efficiency. This study evaluates the fermentation performance of S. cerevisiae in both planktonic and biofilm states under standard and high-carbon media. During a 96-hour fermentation, planktonic cultures consumed glucose within 24 h, whereas biofilm-associated cells required 48 h due to diffusion constraints within the extracellular polymeric substance (EPS) matrix. Under standard conditions, ethanol production at 48 h was comparable between planktonic and biofilm cultures. In high-carbon medium, biofilm cultures exhibited greater ethanol production at 48 h, while planktonic cultures reached their maximum levels earlier, at 24 h, suggesting distinct ethanol production kinetics under high-glucose conditions, potentially consistent with differences in overflow metabolism in biofilm-grown cells. Despite the delay in ethanol accumulation, biofilm-associated yeast demonstrated structural stability and metabolic resilience under high-substrate conditions. These findings highlight the potential of biofilm-based fermentation systems for industrial processes that require enhanced stress tolerance and sustained ethanol productivity under demanding conditions.