title: Immobilised cells of Pachysolen tannophilus yeast for ethanol production from crude glycerol.
abstract: 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-1h-1at a 25gL-1concentration 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-1h-1, while the medium dilution rate in the reactor was 0.062±0.001h-1. 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.
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, 1/3, Lenin Hills, 119991, Moscow, Russia.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Stepanov
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, 1/3, Lenin Hills, 119991, Moscow, Russia. Electronic address: elena_efremenko@list.ru.
authors.forename: Elena
authors.initials: E
authors.lastname: Efremenko
mesh_terms: D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology; D018914:Cells, Immobilized / Q000378:metabolism; D015925:Cryopreservation / Q000379:methods; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005990:Glycerol / Q000378:metabolism; D007218:Industrial Microbiology; D004718:Saccharomycetales / Q000378:metabolism*
chemical_list: D056804:Biofuels; D000431:Ethanol; D005990:Glycerol
keywords: Crude glycerol; Ethanol; Immobilised cells; Pachysolen tannophilus; Poly(vinyl alcohol) cryogel