Immobilized cells

Microbial, plant, and animal cells fixed onto solid surfaces or trapped within gels. They enable bioconversions that isolated enzymes alone cannot perform, and they also serve in biosensors. Entrapment now dominates as the immobilization method; suitable gels range from agar, alginates, and carrageenans to polyacrylamides and polyurethane. Because the cells stay put while the liquid flows past, processes can run continuously with easy product separation — a major practical advantage in brewing, wastewater treatment of food effluents, and the production of organic acids.