Mass transfer resistances in mesoporous silica‐alginate/chitosan encapsulated <scp> <i>Saccharomyces cerevisiae</i> </scp> for bioethanol production

Abstract Microbial cell encapsulation for bioethanol production offers several benefits, including protection of cells from harsh fermentation conditions and simplification of their recovery and reuse. However, a significant challenge in microbial encapsulation is mass transfer resistance. In this study, a mesoporous membrane was designed and examined for the first time to address substrate mass transfer issues. The capsules were named G‐0.75, G‐1.5, and G‐3, corresponding to the amounts of glucose (0.75, 1.5, and 3 g) used as a pore‐forming agent. Simulation results showed that in the conventional G‐0 capsules, substrate concentration (fermentable sugar) was depleted at a radius of 0.6, indicating significant resistance to mass transfer. In the mesoporous G‐3 capsules, over 40% of the substrate reached the centre, suggesting reduced mass transfer resistance compared to G‐0. When an effectiveness factor accounting for mass transfer resistance was included, the substrate concentration improved in each capsule, with glucose reaching a radius of 0.2 in G‐0 and more than 50% of the substrate reaching the centre in G‐3. Additionally, halving the particle size allowed 10% of the substrate to reach the centre in G‐0, while approximately 80% did so in G‐3. These findings demonstrate, for the first time, how both glucose‐induced mesoporosity and particle size reduction influence mass transfer resistance in bioethanol production, alongside the kinetics and diffusion data essential for process design, modelling, simulation, and optimization. This represents a significant advancement for heterogeneous bioprocesses.