title: Physiological studies related to the immobilization of Penicillium chrysogenum and penicillin production.
abstract: Using the production of penicillin by Penicillium chrysogenum as a model system, certain physiological aspects of immobilized and free cell cultures were compared. Reducing the immobilized viable spore loading (from 4 x 10(4) to 2 x 10(3) spores ml-1 gel) and initial bead diameter (from 3.5-4.0 to 1.5-2.0 mm) gave rise to an increase in the penicillin titer from 0.2 to 1.2 g l-1. Using these conditions in immobilized cell culture the growth phase was prolonged and the duration of expression of the isopenicillin N synthase gene (pcbC) was significantly extended when compared with free cell culture (150 h as opposed to 100 h). During the period of maximum penicillin production, different penicillin biosynthetic intermediates accumulated in the broth of free and immobilized cell cultures, reflecting a fundamental difference in cell physiology. Although the maximum specific productivity of penicillin production was reduced by immobilization, the average specific productivity increased when compared to free cell fermentation.
authors.affiliation: Division of Biotechnology, School of Biological and Health Sciences, University of Westminster, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Mussenden
authors.forename: T
authors.initials: T
authors.lastname: Keshavarz
authors.forename: G
authors.initials: G
authors.lastname: Saunders
authors.forename: C
authors.initials: C
authors.lastname: Bucke
mesh_terms: D001709:Biotechnology / Q000379:methods; D015152:Blotting, Northern; D002351:Carrageenan; D005285:Fermentation; D007700:Kinetics; D010088:Oxidoreductases / Q000096:biosynthesis; D010406:Penicillins / Q000096:biosynthesis*; D010408:Penicillium chrysogenum / Q000254:growth & development / Q000502:physiology*; D012331:RNA, Fungal / Q000235:genetics / Q000302:isolation & purification; D013172:Spores, Fungal / Q000502:physiology; D013997:Time Factors
chemical_list: D010406:Penicillins; D012331:RNA, Fungal; D002351:Carrageenan; D010088:Oxidoreductases; C038370:isopenicillin N synthetase