title: Kinetics of ethanol production from carob pods extract by immobilized Saccharomyces cerevisiae cells.
abstract: Kinetics of ethanol production from carob pods extract by immobilized S. cerevisiae cells in static and shake flask fermentation have been investigated. Shake flask fermentation proved to be a better fermentation system for the production of ethanol than static fermentation. The optimum values of ethanol concentration, ethanol productivity, ethanol yield, and fermentation efficiency were obtained at pH range 3.5-6.5 and temperature between 30-35 degrees C. A maximum ethanol concentration (65 g/L), ethanol productivity (8.3 g/Lh), ethanol yield (0.44 g/g), and fermentation efficiency (95%) was achieved at an initial sugar concentration of 200, 150, 100, and 200 g/L, respectively. The highest values of specific ethanol production rate and specific sugar uptake rate were obtained at pH 6.5, temperature 40 degrees C, and initial sugar concentration of 100 g/L. Other kinetic parameters, biomass concentration, biomass yield, and specific biomass production rate were maximum at pH 5.5, temperature 30 degrees C, and initial sugar concentration 150 g/L. Under the same fermentation conditions non-sterilized carob pod extract gave higher ethanol concentration than sterilized medium. In repeated batch fermentations, the immobilized S. cerevisiae cells in Ca-alginate beads retained their ability to produce ethanol for 5 d.
authors.affiliation: Department of Food Science and Technology, Aristotelian University of Thessaloniki, Greece.
authors.forename: T
authors.initials: T
authors.lastname: Roukas
mesh_terms: D003470:Culture Media; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005685:Galactans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008351:Mannans; D053149:Plant Gums; D011134:Polysaccharides / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D013696:Temperature
chemical_list: D003470:Culture Media; D005685:Galactans; D008351:Mannans; D053149:Plant Gums; D011134:Polysaccharides; D000431:Ethanol; C017471:locust bean gum