%0 Journal Article
%@ 13858947
%A Patnaik, P R
%D 2002
%F open:906
%I Elsevier Science
%J Chemical Engineering Journal
%K Recombinant fermentation; GAPDH; Copy number variance; Batch versus fed-batch fermentation
%N 3
%P 357-366
%T Comparative evaluation of batch and fed-batch bioreactors for GAPDH production by recombinant Escherichia coli with distributed plasmid copy number
%U http://crdd.osdd.net/open/906/
%V 87
%X In large bioreactors, there is normally a distribution of plasmid copy numbers among the recombinant cells. This has been modelled here by a Gaussian distribution. For the production of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by Escherichia coli containing the plasmid pBR Eco gap, the performances of batch and fed-batch fermentation have been compared for mean copy numbers between 8 and 12 per cell. In both modes of operation, GAPDH activity increased with copy number but biomass concentration decreased, suggesting that optimum performance may be possible by having a distribution of copy numbers in the starting culture.    Since GAPDH activity per unit biomass attained maximum values at the same point in time (3.12 h) for all copy numbers, the effect of a Gaussian distribution of copy numbers with different variances on the performance at this time was studied. Fed-batch required smaller optimum variances than batch fermentation, which allows easier preparation of seed cultures and greater segregational stability in the former case. Although fed-batch operation also generated larger peak activities of GAPDH, this improvement decreased as the copy number increased, again indicating an optimum copy number and its variance.  
%Z Copyright of this article belongs to Elsevier Science.