1,721,029 research outputs found
Sucrose inversion by gelatin-entrapped cells of yeast (Saccharomyces cerevisiae)
No full textSucrose hydrolysis by inveratyse-active yeast cells (S. cerevisiae) entrapped in gelatin was investigated using different types of miniaturized reactors. The entrapped preparations showed the highest operational stability in a continuous stirred-tank reactor. The invertase activity of the entrapped preparation was found to be almost independent of the buffer concentration so that sucrose inversion may be conducted in a non-buffered medium
Gelatin-entrapped whole-cell invertase
No full textThe investigated byocatalyst consists of gelatin entrapped cells of Saccharomyces cerevisiae retaining invertase activity.Comparative examination of pH profile, apparent Km saturation velocity and activation energy indicates that thee entrapment procedures did not influence invertase affinity with sucrose but lead to some of activity probably due to either enzyme inactivation or cell wall impairment as well as substrate diffusion limitation in the gel matrix
Intrappolamento di cellule di lievito in gel di polivinilalcol: una tecnica di immobilizzazione che mantiene inalterata l’integrità metabolica
No full textA new method of whole microbial cell immobilization
No full textA simple method for producing gelatin immobilized microbial cells is described.. The microorganism used as an example was baker’s yeast ( Saccharomyces cerevisiae). The gel particles containing these cells were utilised as an immobilized enzyme (invertase) both in stirred batch and packed bed system
Immobilization of yeast cells by adhesion on tuff granules
No full textA method for immobilizing yeast cells (Saccharomyces cerevisiae) possessing invertase activity by direct adhesion on tuff granules coated with insolubilised gelatin is described. The immobilized cells, firmly fixed as a monolayer onto the surface of the support granules display catalytic properties (in terms of apparent Km) close to free cells and are particularly suitable for continous sucrose hydrolysis in a fixed-bed reactor. From an industrial point of view, the immobilization method described here has two advantages over other immobilization methods, i.e. the immobilized yeast cells have a firmly good operational stability and their proliferation on tuff granules can be controlled
Oxidized starch as a hardening agent in the gelatin-immobilization of living yeast cells
No full textPeriodate-oxidized starch (oxystarch) was shown to be a good substitute for formaldehyde or glutaraldehyde as hardening agents in an immobilization procedure of microbial cells within gelatin. In fact, contrary to both aldehydes, oxystarch has no antimicrobial activity so that the immobilized cells retain their viability. Cell loading and mechanical stability of the immobilizates make them suitable for operations in continuous bioreactors
Immobilization of Saccharomyces cerevisiae cells to protein G-Sepharose by cell wall engineering.
No full textIn this work, we explored the possibility of using the targeting of a heterologous protein to the cell wall of Saccharomyces cerevisiae, by fusing it to a cell wall protein, to construct yeast strains whose cells display on their surface proteins that bind to a matrix, so as to achieve the immobilization of the whole cells. With this aim, we created a gene fusion that comprises the region responsible for attachment of a cell wall protein to the cell wall, and the IgG binding region of staphylococcal protein A, and expressed it in the mnn1mnn9 strain of S. cerevisiae. The surface display of the protein A-Icwp fusion protein was positively monitored; however, direct immobilization of the cells on an IgG-Sepharose matrix did not produce the expected results, probably due to the fusion protein not being completely exposed on the surface of the cells. To solve this problem we incubated the cells first with rabbit preimmune serum and then with goat anti-rabbit IgGs, so as to create a complex (yeast cell-protein A-rabbit IgG-goat IgG). Cells treated in this way were successfully immobilized on a protein G-Sepharose matrix, due to the binding properties of goat IgGs to streptococcal protein G
Tuff as a convenient material for supporting immbilized invertase-active whole cells of Saccharomyces cerevisiae
No full textA simple method for fixing invertase-active whole cells of yeast (S. cerevisiae) on tuff granules by gelatin is presented. Some kinetic and operative properties of the resulting preparation have been investigated and compared with the corresponding ones of the unsupported gelatin-immobilized whole-cell invertase. Except for a difference in the activity yield, both preparations showed similar kinetic properties. From the operative point of view, the supported preparation was shown to be particularly suitable for continuous hydrolysis of sucrose in a packed bed reactor
Immobilization of viable yeast cells within polyaldheyde-hardened gelatin gel
No full textA gel-entrapment method particularly suitable for viable cells is described. The gel matrix is gelatin insolubilized by interaction with polymeric aldehydes (polyaldehydes) prepared by periodate oxidation of polysaccharides such as starch and dextran. The viability of the entrapped cells is evidenced by growth measurements and by SEM analysis of the immobilizate
PVA-GEL (LENTIKATS) AS A NEW AND EFFECTIVE MATRIX FOR YEAST CELL IMMOBILIZATION AIMED AT HETEROLOGOUS PROTEIN PRODUCTION.
No full textImmobilization of 3 yeasts in a commercial, polyvinyl alcohol (PVA) gel bead system, and its effects on cell cell viability and heterologous protein production are described. The yeasts Saccharomyces cerevisiae, Kluyveromyces lactis and Zygosaccharomyces bailii were immobilized using the Lentikats® system. All 3 species remained viable after immobilization, reaching a max. immobilized biomass of 100 mg dry wt. cells/cm3. The beads were mechanically stable, and could be used in stirred-tank bioreactors. Continuous production of glycoamylase (glucan 1,4-α-glucosidase) by K. lactis and interleukin 1-beta by Z. bailii were demonstrated
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