title: Improvement of Bacillus thuringiensis bioinsecticide production by sporeless and sporulating strains using response surface methodology.
abstract: Statistical experimental designs, involving a Plackett-Burman design followed by a rotatable central composite design were used to optimize the culture medium constituents for Bacillus thuringiensis bioinsecticide production. This was carried out by using firstly an asporogenic strain and extrapolated to some sporeless and sporulating strains. Initial screening of production parameters was performed and the variables with statistically significant effects on delta-endotoxin production were identified: glucose, glycerol, yeast extract and MnSO(4). These variables were selected for further optimization by response surface methodology. The obtained results revealed that the optimum culture medium for delta-endotoxin production consists of 22.5 g/l of glucose, 4.8g/l of glycerol, 5.8 g/l of yeast extract and 0.008 g/l of MnSO(4). Under these conditions, delta-endotoxin production was 2,130 and 2,260 mg/l into 250 and 1,000 ml flask respectively, which represent more than 38% improvement in toxin production over the basal medium (1,636 mg/l). Such medium composition was shown to be suitable for overproducing delta-endotoxins by sporeless and sporulating strains.
authors.affiliation: Laboratoire de Protection et Amélioration des Plantes (Equipe Biopesticides), Center of Biotechnology of Sfax, University of Sfax, P.O. Box 1177, 3018 Sfax, Tunisia.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Ben Khedher
authors.forename: Amel
authors.initials: A
authors.lastname: Kamoun
authors.forename: Samir
authors.initials: S
authors.lastname: Jaoua
authors.forename: Nabil
authors.initials: N
authors.lastname: Zouari
mesh_terms: D001413:Bacillus thuringiensis / Q000502:physiology*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D003470:Culture Media / Q000737:chemistry* / Q000494:pharmacology; D004731:Endotoxins / Q000096:biosynthesis* / Q000235:genetics; D006460:Hemolysin Proteins / Q000096:biosynthesis* / Q000235:genetics; D007306:Insecticides / Q000378:metabolism*; D013171:Spores, Bacterial / Q000235:genetics
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D003470:Culture Media; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis