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Plasmid stability in a recombinant S cerevisiae strain secreting a bifunctional fusion protein
Author(s) -
Altıntaş M Mete,
Kırdar Betül,
Önsan Z İlsen,
Ülgen Kutlu Ö
Publication year - 2001
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.424
Subject(s) - plasmid , saccharomyces cerevisiae , bacillus subtilis , recombinant dna , fermentation , strain (injury) , starch , biology , population , plasmid preparation , amylase , chemistry , microbiology and biotechnology , biochemistry , gene , enzyme , genetics , bacteria , pbr322 , demography , anatomy , sociology
The recombinant Saccharomyces cerevisiae strain, YPB‐G, producing and secreting Bacillus subtilis α‐amylase and Aspergillus awamori glucoamylase as a fusion protein yielded efficient utilisation of starch. A segregated population balance model has been used to determine the probability of plasmid loss and plasmid copy number. The kinetics of cell growth and product (fusion protein) formation were based on a genetically structured model. The predictions were compared with the experimental observations obtained for the unstable recombinant S cerevisiae cells in a 1.5 dm −3 batch bioreactor with 30 g dm 3 initial starch under non‐aerated conditions. The main advantage of the present model is that three different genetic classes were defined on the basis of the existence of plasmid and of the expression of the enzymes, ie cells containing plasmids and expressing the gene product, x 1 ; cells containing plasmids and but not expressing the gene product, x 2 ; and cells without plasmids, x 3 . It is confirmed by this model that the cells without plasmids outgrow and dominate in the fermentation medium (2.27 g dm −3 vs 0.51 g dm −3 ) as more and more glucose becomes available by the degradation of starch. © 2001 Society of Chemical Industry