By optimizing the fermentation conditions, the KGA yield reached 82.4 g/L. In contrast to the pure compound KGA, extracellular polymers (EPS) are complex secondary metabolites produced by microorganisms. Fermentation is a whole-cell biosynthesis process that involves multiple enzymes and native pathways. Biocatalysis, which can be performed by whole cells and isolated enzymes, has become a topic of public interest for its potential use in the chemical industry in manufacturing, monitoring, and waste management. To conclude, this Special Issue on "Microbial Biocatalysis" provides a comprehensive overview of the recent developments in catalyst discovery, its modification, and process intensification for whole-cell catalysis in the fermentation, biotransformation, or biodegradation processes.