A new methodology for plant cell viability assessment using intracellular esterase activity

A plant cell suspension culture of Alfalfa (Medicago sativa L.) was grown i n a bioreactor using a batch procedure. The cytoplasmic esterase activity ( EC 3.1) was extracted from the cells and measured during cultivation using fluorescein diacetate as the fluorogenic substrate. This enzymatic activity was conclusively found to be correlated to cell viability assessed with th e membrane integrity test using the trypan blue dye. This new viability det ermination method is convenient, simple and can be reproduced because: (1) the difficult step of counting the cells when using the trypan blue exclusi on method is avoided and (2) the esterase activity level per viable cell co nstituted of numerous enzymes depends on cell viability but is independent of cellular metabolism.