title: Operation of fluidized-bed bioreactor containing immobilized yeast cells and the diacetyl levels of green beer.
abstract: A fluidized-bed bioreactor containing yeast cells immobilized in calcium alginate gel was operated by means of a circulating wort system. The optimum volume fraction of gel beads was found to be 0.40 (phi, v/v) for fermentation. The effects of the flow rates of the wort on the period of the primary fermentation and the diacetyl levels in green beer were studied under the conditions of the volume fraction of gel beads at phi = 0.40, the fermentation temperature at 10 degrees C, and the ratio of circulation at n = 5. The experimental results indicated that the period of the primary fermentation was shortened as the flow rate of wort increased, whereas the concentration of diacetyl increased with the increasing flow rate of the wort. The period of the primary fermentation and the concentration of the diacetyl were found to be 14 h and 0.5 ppm respectively, when the residence time tau t in the reactor was 2.8 h.
authors.affiliation: Department of Food Engineering, Dalian Institute of Light Industry.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Wang
authors.forename: N Q
authors.initials: NQ
authors.lastname: Zhang
authors.forename: J Z
authors.initials: JZ
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: W T
authors.initials: WT
authors.lastname: Liu
mesh_terms: D001515:Beer; D003931:Diacetyl / Q000378:metabolism*; D005285:Fermentation; D005782:Gels; D007218:Industrial Microbiology / Q000295:instrumentation / Q000379:methods; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D005782:Gels; D003931:Diacetyl