title: Continuous cultivations of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus: Growth yields and morphological characterization.
abstract: The growth stoichiometry of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus was determined in glucose-limited chemostat cultivations using a chemically defined medium. This strain produces adipoyl-7-aminodeacetoxycephalosporanic acid (ad-7-ADCA) when it is fed with adipic acid. The biomass yield and maintenance coefficients for the strain were similar to those found for penicillin-producing strains of Penicillium chrysogenum. The maximum specific growth rate in the chemostat was found to be 0.11 h(-1). Metabolic degradation of adipate was found to take place in significant amounts only at dilution rates below 0.03 h(-1). After three to five residence times, adipate degradation and ad-7-ADCA production disappeared, and this allowed determination of the biomass yield coefficient on adipate. The morphology was measured at different dilution rates and the mean total hyphal length and mean number of tips both increased with an increase in dilution rate from 0.015 to 0.065 h(-1). Both variables decreased when the dilution rate was increased above 0.065 h(-1). A correlation between mean total hyphal length and productivity of ad-7-ADCA was found.
authors.affiliation: Center for Process Biotechnology, BioCentrum-DTU, Building 223, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: J
authors.initials: J
authors.lastname: Robin
authors.forename: G
authors.initials: G
authors.lastname: Lettier
authors.forename: M
authors.initials: M
authors.lastname: McIntyre
authors.forename: H
authors.initials: H
authors.lastname: Noorman
authors.forename: J
authors.initials: J
authors.lastname: Nielsen
mesh_terms: D000272:Adipates / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology; D018929:Cell Culture Techniques / Q000379:methods*; D048429:Cell Size / Q000502:physiology; D002511:Cephalosporins / Q000096:biosynthesis* / Q000378:metabolism*; D005947:Glucose; D007700:Kinetics; D007769:Lactams / Q000378:metabolism; D008954:Models, Biological; D025282:Mycelium / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D010408:Penicillium chrysogenum / Q000166:cytology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity; D013302:Streptomyces / Q000145:classification / Q000201:enzymology* / Q000235:genetics
chemical_list: D000272:Adipates; D002511:Cephalosporins; D007769:Lactams; D011994:Recombinant Proteins; C424182:adipoyl-7-amino-3-deacetoxycephalosporanic acid; C029900:adipic acid; C014320:7-aminodesacetoxycephalosporanic acid; D005947:Glucose