Document Detail

Airlift-driven fibrous-bed bioreactor for continuous production of glucoamylase using immobilized recombinant yeast cells.
MedLine Citation:
PMID:  19539672     Owner:  NLM     Status:  MEDLINE    
Continuous production of a fungal glucoamylase by immobilized recombinant Saccharomyces cerevisiae strain C468 containing plasmid pGAC9. Yeast cells were immobilized on hydrophilic cotton cloth in an inverse internal loop airlift-driven bioreactor. Free-cell culture in the airlift and stirred tank bioreactors confirmed the plasmid instability of the recombinant yeast. Enhanced glucoamylase productivity and plasmid stability were observed both in the free and immobilized cell cultures in the airlift bioreactor system. The glucoamylase level of the free-cell culture in the airlift bioreactor was approximately 20% higher than that in the in stirred tank bioreactor due to high cell density (cell dry weight/volume of bioreactor) and fraction of the plasmid-carrying cells. A potentially high glucoamylase activity of 161U/L and a corresponding volumetric productivity of 3.5U/Lh were achieved when a cell density of approximately 85g/L (or 12.3g/g fiber) was attained in the fibrous-bed immobilized cell bioreactor system. The stable glucoamylase production was achieved after five generations, at which time a fraction of approximately 62% of the plasmid-carrying cells was realized in the immobilized cell system. Plasmid stability was increased for the immobilized cells during continuous culture at the operating dilution rate. The volumetric and specific productivities and fraction of plasmid-carrying cells in the immobilized cell system were higher than in the free-cell counterpart, however. This was in part due to the high viability (approximately 80%) in the immobilized cell system and the selective immobilization of the plasmid-carrying cells in the fibrous bed, and perhaps increased plasmid copy number.
Peter Kilonzo; Argyrios Margaritis; Maurice Bergougnou
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-06-17
Journal Detail:
Title:  Journal of biotechnology     Volume:  143     ISSN:  1873-4863     ISO Abbreviation:  J. Biotechnol.     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-07-28     Completed Date:  2009-11-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8411927     Medline TA:  J Biotechnol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  60-8     Citation Subset:  IM    
Department of Chemical and Biochemical Engineering, University of Western Ontario, Ontario, Canada.
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MeSH Terms
Aspergillus / enzymology
Biotechnology / methods
Cell-Free System
Equipment Design
Ethanol / chemistry
Glucan 1,4-alpha-Glucosidase / biosynthesis*,  chemistry
Glucose / chemistry
Industrial Microbiology / methods
Microscopy, Electron, Scanning / methods
Plasmids / metabolism
Saccharomyces cerevisiae / enzymology,  metabolism*
Time Factors
Reg. No./Substance:
50-99-7/Glucose; 64-17-5/Ethanol; EC 1,4-alpha-Glucosidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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