NADPH-dependent glutamate dehydrogenase in Penicillium chrysogenum is involved in regulation of beta-lactam production.
The interactions between the ammonium assimilatory pathways and beta-lactam production were investigated by disruption of the NADPH-dependent glutamate dehydrogenase gene (gdhA) in two industrial beta-lactam-producing strains of Penicillium chrysogenum. The strains used were an adipoyl-7-ADCA- and a penicillin-producing strain. The gdhA gene disruption caused a decrease in maximum specific growth rate of 26 % and 35 % for the adipoyl-7-ADCA-producing strain and the penicillin-producing strain, respectively, compared to the corresponding reference strains. Interestingly, no beta-lactam production was detected in either of the DeltagdhA strains. Supplementation with glutamate restored growth but no beta-lactam production was detected for the constructed strains. Cultures with high ammonium concentrations (repressing conditions) and with proline as nitrogen source (de-repressed conditions) showed continued beta-lactam production for the reference strains whereas the DeltagdhA strains remained non-productive under all conditions. By overexpressing the NAD-dependent glutamate dehydrogenase, the specific growth rate could be restored, but still no beta-lactam production was detected. The results indicate that the NADPH-dependent glutamate dehydrogenase may be directly or indirectly involved in the regulation of beta-lactam production in industrial strains of P. chrysogenum.
Thykaer
Jette
J
Center for Microbial Biotechnology, Technical University of Denmark, Building 223, DK-2800 Lyngby, Denmark.
Rueksomtawin
Kanchana
K
Center for Microbial Biotechnology, Technical University of Denmark, Building 223, DK-2800 Lyngby, Denmark.
Noorman
Henk
H
DSM-Anti-Infectives, Industrial Pharmaceutical Products Division, Wateringsweg 1, PO Box 1, NL-2600 MA Delft, Denmark.
Nielsen
Jens
J
Center for Microbial Biotechnology, Technical University of Denmark, Building 223, DK-2800 Lyngby, Denmark.
D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D018533:Biomass; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018086:Glutamate Dehydrogenase (NADP+) / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D016254:Mutagenesis, Insertional; D010408:Penicillium chrysogenum / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D011392:Proline / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D047090:beta-Lactams / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D005656:Fungal Proteins; D000644:Quaternary Ammonium Compounds; D047090:beta-Lactams; D018698:Glutamic Acid; D011392:Proline; D018086:Glutamate Dehydrogenase (NADP+)