title: Effects of acetate on Kluyveromyces marxianus DSM 5422 growth and metabolism.
abstract: Metabolically active cells produce a wide array of metabolites that can inhibit their growth. Acetate is a widely known preservative, and it is also produced by yeast cells during their growth. Kluyveromyces marxianus DSM 5422 is a promising yeast strain that could be employed in biotechnological processes, but the knowledge of its stress physiology is scarce. Here, we investigate the effects of acetate on growth and changes in cell population structure during adaptation to elevated concentrations of acetate in K. marxianus DSM 5422. Our results indicate that acetate inhibits growth in a pH-dependent manner and has pronounced effects if yeast is grown on lactose or galactose. When challenged with acetate, culture extends lag phase, during which cells adapt to elevated acetate concentrations, and growth reoccurs, albeit at a slower rate, when majority of the population is acetate resistant. Acetate resistance is maintained only if acetate is present in the media or if the culture has reached end of active growth phase. This study shows possible caveats in lactose fermentation with K. marxianus and gives a further perspective in non-conventional yeast applications in biotechnology.
authors.affiliation: Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str 1, Riga, LV1004, Latvia.
authors.forename: Jekaterina
authors.initials: J
authors.lastname: Martynova
authors.affiliation: Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str 1, Riga, LV1004, Latvia. agnese.kokina@lu.lv.
authors.forename: Agnese
authors.initials: A
authors.lastname: Kokina
authors.affiliation: Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str 1, Riga, LV1004, Latvia.
authors.forename: Juris
authors.initials: J
authors.lastname: Kibilds
authors.affiliation: Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str 1, Riga, LV1004, Latvia.
authors.forename: Janis
authors.initials: J
authors.lastname: Liepins
authors.affiliation: Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str 1, Riga, LV1004, Latvia.
authors.forename: Rita
authors.initials: R
authors.lastname: Scerbaka
authors.affiliation: Institute of Microbiology and Biotechnology, University of Latvia, Jelgavas str 1, Riga, LV1004, Latvia.
authors.forename: Armands
authors.initials: A
authors.lastname: Vigants
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000222:Adaptation, Physiological / Q000187:drug effects; D019149:Bioreactors; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D005690:Galactose / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007716:Kluyveromyces / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism*; D007785:Lactose / Q000737:chemistry
chemical_list: D000085:Acetates; D003470:Culture Media; D007785:Lactose; D005690:Galactose
keywords: Acetate stress; Kluyveromyces marxianus; Lactose; Non-conventional yeasts; Population heterogenity