title: How physiological and cultural conditions influence heterologous protein production in Kluyveromyces lactis.
abstract: The optimization and scale-up of a specific protein production process have to take into account cultural conditions as well as cell physiology of growth and influence of foreign protein expression on host cell metabolism. Growth on cheap substrates, efficient secretion ability and a weaker tendency to hypermannosilate proteins than S. cerevisiae, make K. lactis an excellent and well-accepted host for heterologous protein production, even for human use. A fairly good heterologous glucoamylase yield and the setting of the optimal conditions to produce it were obtained expressing the Arxula adeninivorans glucoamylase in a strain of K. lactis and its isogenic mutant, which seems to have higher secretion ability. We performed batch cultures of both strains to analyze the influence of different physiological and environmental parameters on glucoamylase production/secretion. Interestingly, the maintenance of pH in the range of neutrality causes the consumption of a larger amount of carbon source, a longer time of production and a better stability of the active form of the enzyme, thus increasing biomass and glucoamylase production. Furthermore, the enrichment of the culture medium adds up to the action of pH control, forcing the mutant production/secretion to higher levels.
authors.affiliation: Dipartimento di Scienze Biomolecolari e Biotecnologie, Sezione di Biochimica Comparata, Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Merico
authors.forename: Daniele
authors.initials: D
authors.lastname: Capitanio
authors.forename: Ileana
authors.initials: I
authors.lastname: Vigentini
authors.forename: Bianca Maria
authors.initials: BM
authors.lastname: Ranzi
authors.forename: Concetta
authors.initials: C
authors.lastname: Compagno
mesh_terms: D050260:Carbohydrate Metabolism; D000431:Ethanol / Q000138:chemical synthesis; D005087:Glucan 1,4-alpha-Glucosidase / Q000096:biosynthesis* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D007716:Kluyveromyces / Q000235:genetics* / Q000502:physiology; D010100:Oxygen / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013213:Starch / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D000431:Ethanol; D013213:Starch; D005087:Glucan 1,4-alpha-Glucosidase; D010100:Oxygen