title: Immobilisation increases yeast cells' resistance to dehydration-rehydration treatment.
abstract: This study was performed with the goal of revealing if the dehydration procedure used in our new immobilisation method noticeably decreases the viability of yeast cells in immobilised preparations. Various yeasts were used in this research: Saccharomyces cerevisiae cells that were rather sensitive to dehydration and had been aerobically grown in an ethanol-containing medium, a recombinant strain of S. cerevisiae grown in aerobic conditions which were completely non-resistant to dehydration and an anaerobically grown bakers' yeast strain S. cerevisiae, as well as a fairly resistant Pichia pastoris strain. Experiments performed showed that immobilisation of all these strains essentially increased their resistance to a dehydration-rehydration treatment. The increase of cells' viability (compared with control cells dehydrated in similar conditions) was from 30 to 60%. It is concluded that a new immobilisation method, which includes a dehydration stage, does not lead to an essential loss of yeast cell viability. Correspondingly, there is no risk of losing the biotechnological activities of immobilised preparations. The possibility of producing dry, active yeast preparations is shown, for those strains that are very sensitive to dehydration and which can be used in biotechnology in an immobilised form. Finally, the immobilisation approach can be used for the development of efficient methods for the storage of recombinant yeast strains.
authors.affiliation: Laboratory of Cell Biology, Institute of Microbiology and Biotechnology, University of Latvia, Kronvald blvd., 4, Riga LV-1586, Latvia. Electronic address: borovikovadiana@inbox.lv.
authors.forename: Diana
authors.initials: D
authors.lastname: Borovikova
authors.affiliation: Laboratory of Cell Biology, Institute of Microbiology and Biotechnology, University of Latvia, Kronvald blvd., 4, Riga LV-1586, Latvia.
authors.forename: Linda
authors.initials: L
authors.lastname: Rozenfelde
authors.affiliation: Institute of Silicate Materials, Riga Technical University, Azenes Str., 14/24, Riga LV-1007, Latvia.
authors.forename: Ilona
authors.initials: I
authors.lastname: Pavlovska
authors.affiliation: Laboratory of Cell Biology, Institute of Microbiology and Biotechnology, University of Latvia, Kronvald blvd., 4, Riga LV-1586, Latvia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Rapoport
mesh_terms: D001709:Biotechnology; D002470:Cell Survival / Q000187:drug effects*; D003681:Dehydration; D000431:Ethanol / Q000737:chemistry / Q000494:pharmacology; D005285:Fermentation / Q000187:drug effects*; D005440:Fluid Therapy; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development*
chemical_list: D000431:Ethanol
keywords: Dehydration; Immobilisation; Resistance; Viability; Yeast