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Performance of different immobilized‐cell systems to efficiently produce ethanol from whey: fluidized batch, packed‐bed and fluidized continuous bioreactors
Author(s) -
Gabardo Sabrina,
Rech Rosane,
Ayub Marco Antônio Záchia
Publication year - 2012
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.3749
Subject(s) - kluyveromyces marxianus , bioreactor , bioconversion , fluidized bed , chromatography , chemistry , packed bed , ethanol , dilution , fermentation , biochemistry , yeast , organic chemistry , saccharomyces cerevisiae , physics , thermodynamics
BACKGROUND: The bioconversion of whey into ethanol by immobilized Kluyveromyces marxianus in packed‐bed and fluidized bioreactors is described. Both batch and continuous cultures were analyzed using three different strains of K. marxianus and the effect of the operating mode, temperature, and dilution rates (D) were investigated. RESULTS: All immobilized strains of K. marxianus (CBS 6556, CCT 4086, and CCT 2653) produced similar high yields of ethanol (0.44 ± 0.01 g EtOH g −1 sugar). Significant variations of conversion efficiencies (66.1 to 83.3%) and ethanol productivities (0.78 to 0.96 g L −1 h −1 ) were observed in the experiments with strain K. marxianus CBS 6556 at different temperatures. High yields of ethanol were obtained in fluidized and packed‐bed bioreactors continuous cultures at different D (0.1 to 0.3 h −1 ), with the highest productivity (3.5 g L −1 h −1 ) observed for D = 0.3 h −1 in the fluidized bioreactor (87% of the maximal theoretical conversion), whereas the highest ethanol concentration in the streaming effluent (28 g L −1 ) was obtained for D = 0.1 h −1 . Electronic micrographs of the gel beads showed efficient cell immobilization. CONCLUSION: Batch and continuous cultivations of immobilized K. marxianus in fluidized and packed‐bed bioreactors enable high yields and productivities of ethanol from whey. Copyright © 2012 Society of Chemical Industry