Continuous mixed strain mesophilic lactic starter production in supplemented whey permeate medium using immobilized cell technology

Technologies with free and immobilised cells for probiotic bifidobacteria production and protection

“…Spherical polymer beads with diameters ranging from 0.3 to 3.0 mm and immobilising active biomass are produced using extrusion or emulsification techniques, by thermal (k-carrageenan, gellan, agarose, gelatin) or ionotropic (alginate, chitosan) gelation of the droplets. Incubation of immobilised cells in a nutritive medium results in the formation of a high cell density region that extends from the bead surface to a radial position where cell growth is prevented due to lack of substrate, or accumulation of inhibitory products and low local pH (Lamboley, Lacroix, Champagne, & Vuillemard, 1997). Biofilm-type cell growth occurring in the gel beads results in a high rate of cell release from the peripheral layer of the beads into the fermentation medium, as a result of high pressure due to cell expansion, collisions and shearing forces in the bioreactor (Sodini-Gallot, Boquien, Corrieu, Lamboley et al, 1997).…”

“…Incubation of immobilised cells in a nutritive medium results in the formation of a high cell density region that extends from the bead surface to a radial position where cell growth is prevented due to lack of substrate, or accumulation of inhibitory products and low local pH (Lamboley, Lacroix, Champagne, & Vuillemard, 1997). Biofilm-type cell growth occurring in the gel beads results in a high rate of cell release from the peripheral layer of the beads into the fermentation medium, as a result of high pressure due to cell expansion, collisions and shearing forces in the bioreactor (Sodini-Gallot, Boquien, Corrieu, Lamboley et al, 1997). In the case of bifidobacteria and LAB that are sensitive to product inhibition, product concentration and pH profiles play a major role on immobilised cell growth and productivity (Masson, Lacroix, & Paquin, 1994;Lamboley et al, 1997;Doleyres et al, 2002a).…”

“…Biofilm-type cell growth occurring in the gel beads results in a high rate of cell release from the peripheral layer of the beads into the fermentation medium, as a result of high pressure due to cell expansion, collisions and shearing forces in the bioreactor (Sodini-Gallot, Boquien, Corrieu, Lamboley et al, 1997). In the case of bifidobacteria and LAB that are sensitive to product inhibition, product concentration and pH profiles play a major role on immobilised cell growth and productivity (Masson, Lacroix, & Paquin, 1994;Lamboley et al, 1997;Doleyres et al, 2002a).…”

An Evaluation of Different Bioreactor Configurations with Immobilized Yeast for Bioethanol Production

“…Stirred tank reactors (STR) have been used to cultivate entrapped cells even though the catalysts are thus exposed to a rather high degree of shear. Natural polymers used to immobilize the cells include pectin (Kesava and Panda, 1996), carrageenan (Lamboley et al, 1997) and alginate (Lamboley et al, 1997;Qureshi and Manderson, 1991;Sarrouh et al, 2007;Hernández et al, 2001). The STR has the advantage of effective agitation system (promoted by the use of an impeller), an easy control of temperature and pH and its continuous operation may be useful in the case of substrate inhibition (Fukuda, 1994).…”

Simultaneous Immunofluorescent Detection of Coentrapped Cells in Gel Beads

“…Stable and reproducible mixed-strain starters in the effluent of a continuous reactor were obtained using this technology, and very high productivity resulted from the high cell density retained in the immobilized cell reactor (7,8). However, a large crosscontamination of beads, initially entrapping pure cultures, was observed during continuous cultures over long fermentation times of 6 to 8 weeks in supplemented whey permeate (7,8) or in milk (14). A theoretical model of cell release from cavities located near the gel bead surfaces has been recently proposed to explain this cross-contamination phenomenon (6).…”