Immobilization of enzymes and whole cells enabled reusable biocatalysts and continuous operation across amino acid and sugar production, using polyacrylamide gels, gel lattices, and immobilization matrices. Dissection and reassembly of cellulolytic enzyme systems from fungal sources demonstrated approaches to biomass deconstruction and cellulose solubilization, guiding enzyme engineering and biomass valorization. Process design and steady-state bioprocessing of amino acids and organic acids with immobilized biocatalysts and continuous reactors illustrated early bioprocess engineering emphasis on continuous production; enzymatic dairy processing via immobilized lactase and bound beta-galactosidase enabled lactose hydrolysis and production of lactose-free dairy ingredients, integrating enzyme technology with food bioprocessing. Historical Significance: Cross-period studies on ethanol production introduced comparative process design approaches and technoeconomic analysis for large-scale fermentation. Rapid ethanol fermentations using vacuum and cell recycle demonstrated high cell density and accelerated production, providing a blueprint for high-rate bioprocessing. Preparation of mutant cellulase-overproducing strains and solid-state fermentation concepts laid foundational strategies for enzyme supply, biomass conversion, and solid-substrate bioprocessing.