MICROBIAL-CELLS IMMOBILIZED IN POLY(VINYL ALCOHOL) CRYOGELS .1. MICROBIAL-CELLS IMMOBILIZED IN POLY(VINYL ALCOHOL) CRYOGELS - BIOCATALYTIC REDUCTION OF CO2 BY THE THERMOPHILIC HOMOACETOGENIC BACTERIUM ACETOGENIUM-KIVUI

The formation of acetate from CO 2 /H 2 gas mixtures by the homoacetate bacterium Acetogenium kivui under various conditions was studied. The advantages and disadvantages of processes based on the use of growing, non-growing and immobilized cells are discussed. Analysis of the kinetics of acetate formation (the concentration of which reached 150-170 mmol/litre in 3 days) in growing culture has shown that the limiting factor is cell lysis. Batch experiments with non-growing cultures demonstrated that, in the absence of lysis, acetate production was constant for at least 1 month, but was considerably inhibited by traces of oxygen, analogously to growing cultures