title: Bifidobacterium longum ATCC 15707 cell production during free- and immobilized-cell cultures in MRS-whey permeate medium.
abstract: Bifidobacterium longum ATCC 15707 cell production was studied in MRS medium supplemented with whey permeate (MRS-WP) during free-cell batch fermentations and continuous immobilized-cell cultures. Very high populations were measured after 12 h batch cultures in MRS-WP medium controlled at pH 5.5 (1.7+/-0.5x10(10) cfu/ml), approximately 2-fold higher than in non-supplemented MRS. Our study showed that WP is a low-cost source of lactose and other components that can be used to increase bifidobacteria cell production in MRS medium. Continuous fermentation in MRS-WP of B. longum immobilized in gellan gum gel beads produced the highest cell concentrations in the effluent (4.9+/-0.9x10(9) cfu/ml) at a dilution rate (D) of 0.5 h(-1). However, maximal volumetric productivity (6.9+/-0.4x10(9) cfu ml(-1)h(-1)) during continuous cultures was obtained at D =2.0 h(-1), and was approximately 9.5-fold higher than during free-cell batch cultures at an optimal pH of 5.5 (7.2x10(8) cfu ml(-1)h(-1)).
authors.affiliation: Dairy Research Centre STELA, Pavillon Paul Comtois, Université Laval, Québec, Quebec Province, G1K 7P4, Canada.
authors.forename: Y
authors.initials: Y
authors.lastname: Doleyres
authors.forename: C
authors.initials: C
authors.lastname: Paquin
authors.forename: M
authors.initials: M
authors.lastname: LeRoy
authors.forename: C
authors.initials: C
authors.lastname: Lacroix
mesh_terms: D001644:Bifidobacterium / Q000254:growth & development* / Q000378:metabolism; D018533:Biomass; D018914:Cells, Immobilized; D003470:Culture Media / Q000378:metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D008894:Milk Proteins / Q000378:metabolism*; D000067816:Whey Proteins
chemical_list: D003470:Culture Media; D008894:Milk Proteins; D000067816:Whey Proteins