caa a22 4500 477106331 CHVBK 20180405111554.0 cr unu---uuuuu 170330e19960201xx s 000 0 eng 10.1007/BF01570069 doi (NATIONALLICENCE)springer-10.1007/BF01570069 Fed-batch production of baker's yeast using millet ( Pennisetum typhoides ) flour hydrolysate as the carbon source [Elektronische Daten] [A Ejiofor, Y Chisti, M Moo-Young] A fermentation medium based on millet (Pennisetum typhoides) flour hydrolysate and a four-phase feeding strategy for fed-batch production of baker's yeast,Saccharomyces cerevisiae, are presented. Millet flour was prepared by dry-milling and sieving of whole grain. A 25% (w/v) flour mash was liquefied with a thermostable 1,4-α-d-glucanohydrolase (EC 3.2.1.1) in the presence of 100 ppm Ca2+, at 80°C, pH 6.1-6.3, for 1 h. The liquefied mash was saccharified with 1,4-α-d-glucan glucohydrolase (EC 3.2.1.3) at 55°C, pH 5.5, for 2 h. An average of 75% of the flour was hydrolysed and about 82% of the hydrolysate was glucose. The feeding profile, which was based on a model with desired specific growth rate range of 0.18-0.23 h−1, biomass yield coefficient of 0.5 g g−1 and feed substrate concentration of 200 g L−1, was implemented manually using the millet flour hydrolysate in test experiments and glucose feed in control experiments. The fermentation off-gas was analyzed on-line by mass spectrometry for the calculation of carbon dioxide production rate, oxygen up-take rate and the respiratory quotient. Off-line determination of biomass, ethanol and glucose were done, respectively, by dry weight, gas chromatography and spectrophotometry. Cell mass concentrations of 49.9-51.9 g L−1 were achieved in all experiments within 27 h of which the last 15 h were in the fedbatch mode. The average biomass yields for the millet flour and glucose media were 0.48 and 0.49 g g−1, respectively. No significant differences were observed between the dough-leavening activities of the products of the test and the control media and a commercial preparation of instant active dry yeast. Millet flour hydrolysate was established to be a satisfactory low cost replacement for glucose in the production of baking quality yeast. Society for Industrial Microbiology, 1996 Millet nationallicence Pennisetum typhoides nationallicence liquefaction nationallicence saccharification nationallicence baker's yeast nationallicence Saccharomyces cerevisiae nationallicence fermentation nationallicence Ejiofor A. Department of Chemical engineering, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada aut Chisti Y. Department of Chemical engineering, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada aut Moo-Young M. Department of Chemical engineering, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada aut Journal of Industrial Microbiology Springer-Verlag 16/2(1996-02-01), 102-109 0169-4146 16:2<102 1996 16 10295 https://doi.org/10.1007/BF01570069 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01570069 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ejiofor A. Department of Chemical engineering, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada aut NATIONALLICENCE 700 1- Chisti Y. Department of Chemical engineering, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada aut NATIONALLICENCE 700 1- Moo-Young M. Department of Chemical engineering, University of Waterloo, N2L 3G1, Waterloo, Ontario, Canada aut NATIONALLICENCE 773 0- Journal of Industrial Microbiology Springer-Verlag 16/2(1996-02-01), 102-109 0169-4146 16:2<102 1996 16 10295 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer