title: Overcome of Carbon Catabolite Repression of Bioinsecticides Production by Sporeless Bacillus thuringiensis through Adequate Fermentation Technology.
abstract: The overcoming of catabolite repression, in bioinsecticides production by sporeless Bacillus thuringiensis strain S22 was investigated into fully controlled 3 L fermenter, using glucose based medium. When applying adequate oxygen profile throughout the fermentation period (75% oxygen saturation), it was possible to partially overcome the catabolite repression, normally occurring at high initial glucose concentrations (30 and 40 g/L glucose). Moreover, toxin production yield by sporeless strain S22 was markedly improved by the adoption of the fed-batch intermittent cultures technology. With 22.5 g/L glucose used into culture medium, toxin production was improved by about 36% when applying fed-batch culture compared to one batch. Consequently, the proposed fed-batch strategy was efficient for the overcome of the carbon catabolite repression. So, it was possible to overproduce insecticidal crystal proteins into highly concentrated medium.
authors.affiliation: Team of Biopesticides (LPIP), Centre of Biotechnology of Sfax, Sfax University, 3018 Sfax, Tunisia.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Ben Khedher
authors.affiliation: Department of Biological & Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.
authors.forename: Samir
authors.initials: S
authors.lastname: Jaoua
authors.affiliation: Department of Biological & Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.
authors.forename: Nabil
authors.initials: N
authors.lastname: Zouari