Document Detail

A microwell platform for the scale-up of a multistep bioconversion to bench-scale reactors: sitosterol side-chain cleavage.
MedLine Citation:
PMID:  20235144     Owner:  NLM     Status:  MEDLINE    
The microwell-scale approach is widely used for screening purposes and one-pot biotransformations, but it has seldom been applied to complex whole cell multistep bioconversions, requiring prolonged incubation periods. The present study aims to contribute to filling this gap. The side-chain cleavage of sitosterol to androstenedione (AD) with Mycobacterium sp. NRRL B-3805 cells was used as a model system, and focus was given to the screening of suitable bioconversion media with 24-well microwell plates. Results show that to perform this particular bioconversion growing cells are preferred over resting cells due to higher conversion yields obtained in aqueous medium. The use of resting cells may nevertheless present an interesting approach provided catalytic activity is retained throughout successive runs. Maintaining suitable aeration levels (air flow of 1 mL/min) allowed minimizing the decay of catalytic activity typically observed alongside consecutive bioconversion runs with resting cells. Microwell plates with dedicated oxygen and pH monitoring capabilities proved effective in media development for complex multistep bioconversions using relatively slow-growing bacteria. Under constant k(L)a (0.044/s) similar AD production and dissolved oxygen profiles were observed in microwell plates and in a bench-scale reactor. Selection of a suitable k(L)a value proved critical, since under lower k(L)a values scale-up proved unsuccessful. The same pattern was observed when other scale-up criteria were evaluated to perform the scale-up of this particular bioconversion. Results gathered seem to validate the proposed approach "from microwell plate to bench-scale fermentor".
Marco P C Marques; Joaquim M S Cabral; Pedro Fernandes
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biotechnology journal     Volume:  5     ISSN:  1860-7314     ISO Abbreviation:  Biotechnol J     Publication Date:  2010 Apr 
Date Detail:
Created Date:  2010-04-01     Completed Date:  2010-06-30     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101265833     Medline TA:  Biotechnol J     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  402-12     Citation Subset:  IM    
IBB-Institute for Biotechnology and Bioengineering, Center for Biological and Chemical Engineering, Instituto Superior T?cnico, Lisboa, Portugal.
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MeSH Terms
Bioreactors / microbiology*
Cell Culture Techniques / instrumentation*
Equipment Design
Equipment Failure Analysis
Mycobacterium / metabolism*
Pilot Projects
Sitosterols / metabolism*
Testosterone / metabolism*
Reg. No./Substance:
0/Sitosterols; 5779-62-4/sitosterol; 58-22-0/Testosterone

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

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