IMPROVED OXYGEN-TRANSFER IN CULTURES OF NOCARDIA-LACTAMDURANS MAINTAINS THE CEPHAMYCIN BIOSYNTHETIC PROTEINS FOR PROLONGED TIME AND ENHANCES THE CONVERSION OF DEACETYLCEPHALOSPORIN INTO CEPHAMYCIN-C
Al. Leitao et al., IMPROVED OXYGEN-TRANSFER IN CULTURES OF NOCARDIA-LACTAMDURANS MAINTAINS THE CEPHAMYCIN BIOSYNTHETIC PROTEINS FOR PROLONGED TIME AND ENHANCES THE CONVERSION OF DEACETYLCEPHALOSPORIN INTO CEPHAMYCIN-C, Journal of biotechnology, 58(1), 1997, pp. 39-50
Batch cultures of Nocardia lactamdurans MA4213 in stirred tank ferment
ers (400 rpm) became oxygen limited after 45 h of incubation. When the
stirrer speed was increased at 36 h from 400 to 600 rpm there was a 5
-fold increase in the dissolved oxygen (DO) in the broth what resulted
in a 2-fold stimulation of cephamycin biosynthesis. Immunoblotting st
udies using antibodies against the alpha-aminoadipyl-cysteinyl-valine
synthetase and the protein P7 (cephem-7-hydroxylase) component of the
methoxylation system showed that cultures with increased DO concentrat
ions maintained high levels of these proteins for an extended period o
f time. Under these conditions there was an enhanced conversion of cep
hamycin intermediates into cephamycin C. Allophane and alumina exerted
a strong stimulatory effect on cephamycin biosynthesis that correlate
d with high DO levels in allophane-or alumina-supplemented cultures at
low agitation speeds. Allophane or alumina supplementation of N. lact
amdurans cultures resulted in a delayed decay of the cephem-7-hydroxyl
ase protein in the cells favoring conversion of the cephamycin interme
diates into cephamycin C. (C) 1997 Elsevier Science B.V.