Physiological and morphological study of encapsulated Saccharomyces cerevisiae
Journal article, 2007
The impact of encapsulation on the anaerobic growth pattern of S. cerevisiae CBS 8066 in a defined synthetic medium over 20 consecutive batch cultivations was investigated. In this period, the ethanol yield increased from 0.43 to 0.46 g/g, while the biomass and glycerol yields decreased by 5 8 and 23%, respectively. The growth rate of the encapsulated cells in the first batch was 0.13 h(-1), but decreased gradually to 0.01 h(-1) within the 20 sequential batch cultivations. Total RNA content of these yeast cells decreased by 39% from 90.3 to 55 mg/g, while the total protein content decreased by 24% from 460 to 350 mg/g. On the other hand, the stored carbohydrates, that is, glycogen and trehalose content, increased by factors of 4.5 and 4 within 20 batch cultivations, respectively. Higher biomass concentrations inside capsules led to a lower glucose diffusion rate through the membrane, and volumetric mass transfer coefficient for glucose was drastically decreased from 6.28 to 1.24 (cm(3)/min) by continuing the experiments. Most of the encapsulated yeast existed in the form of single and non-budding cells after long-term application. (C) 2007 Elsevier Inc. All rights reserved.
proteins
GROWTH-RATE
YEAST
yeast physiology
IMMOBILIZATION
glycogen
ethanol
ACID HYDROLYZATE
FERMENTATION
transfer coefficient
CONTINUOUS CULTIVATION
mass
encapsulation
CELLS
PERFORMANCE
ETHANOL-PRODUCTION
GLUCOSE
Author
Farid Talebnia Rowshan
University of Borås
Chalmers
Mohammad Taherzadeh Esfahani
Chalmers, Chemical and Biological Engineering
Enzyme and Microbial Technology
0141-0229 (ISSN)
Vol. 41 6-7 683-688Subject Categories
Chemical Engineering
DOI
10.1016/j.enzmictec.2007.05.020