title: Optimisation of medium composition for probiotic biomass production using response surface methodology.
abstract: This study was aimed to optimise lactose, inulin and yeast extract concentration and also culture pH for maximising the growth of a probiotic bacterium, Bifidobacterium animalis subsp. lactis in apple juice and to assess the effects of these factors by using response surface methodology. A second-order central composite design was applied to evaluate the effects of these independent variables on growth of the microorganism. A polynomial regression model with cubic and quadratic terms was used for analysis of the experimental data. It was found that the effects involving inulin, yeast extract and pH on growth of the bacterium were significant, and the strongest effect was given by the yeast extract concentration. Estimated optimum conditions of the factors on the bacterial growth are as follows: lactose concentration=9·5 g/l; inulin concentration=38·5 mg/l; yeast extract concentration=9·6 g/l and initial pH=6·2.
authors.affiliation: Department of Microbiology, Faculty of Sciences, Islamic Azad University, Rasht Branch, P.O. Box 41335-3516, Rasht, Iran.
authors.forename: Masumeh
authors.initials: M
authors.lastname: Anvari
authors.affiliation: Department of Chemical Engineering, Faculty of Eng., Guilan University, P. O. Box 3756-41635, Rasht, Iran.
authors.forename: Gholam
authors.initials: G
authors.lastname: Khayati
authors.affiliation: Department of Microbiology, Sciences and Research Branch, Islamic Azad University, Guilan, Iran.
authors.forename: Shora
authors.initials: S
authors.lastname: Rostami
mesh_terms: D001644:Bifidobacterium / Q000254:growth & development*; D018533:Biomass; D003470:Culture Media; D005285:Fermentation; D005638:Fruit; D006863:Hydrogen-Ion Concentration; D007444:Inulin / Q000008:administration & dosage; D007785:Lactose / Q000008:administration & dosage; D027845:Malus; D019936:Probiotics; D015003:Yeasts / Q000737:chemistry
chemical_list: D003470:Culture Media; D007444:Inulin; D007785:Lactose