초록
Screening among naturally occurring yeast strains of Pachysolen spp. that are capable of producing ethanol from glycerol under aerobic conditions identified the most active culture, P. tannophilus Y -475. Conversion of glycerol by this producer immobilised in poly(vinyl alcohol) cryogel resulted in a 90% yield of ethanol relative to the theoretical limit. The maximum rate of alcohol accumulation was 0.64+/-0.01gL<SUP>-1</SUP>h<SUP>-1</SUP> at a 25gL<SUP>-1</SUP> concentration of glycerol in the culture medium. We demonstrated the efficacy of reusing immobilised cells (for a minimum of 16 working cycles for batch mode of crude glycerol conversion to ethanol) and the possibility of long-term (for a minimum of 140h) use of the cells in continuous mode with a maximum process productivity of 0.63+/-0.02gL<SUP>-1</SUP>h<SUP>-1</SUP>, while the medium dilution rate in the reactor was 0.062+/-0.001h<SUP>-1</SUP>. Reduction of metabolic activity did not exceed 5-7% relative to baseline. Immobilised cells were demonstrated to withstand long-term storage in frozen form for at least 2 years while retaining high metabolic activity.