title: Effect of agitation and aeration on production of hexokinase by Saccharomyces cerevisiae.
abstract: A batch culture of Saccharomyces cerevisiae for the production of hexokinase was carried out in a 5-L fermentor containing 3 L of culture medium, which was inoculated with cell suspension (about 0.7 g/L), and left fermenting at 35 degrees C and pH 4.0. The aeration and agitation were adjusted to attain k(L)a values of 15, 60, 135, and 230 h(-1). The highest hexokinase productivity (754.6 U/[L x h]) and substrate-cell conversion yield (0.21 g/g) occurred for a k(L)a of 60 h(-1). Moreover, the formation of hexokinase and cell growth are coupled events, which is in accordance with the constitutive character of this enzyme. Hexokinase formation for kLa > 60 h(-1) was not enhanced probably owing to saturation of the respiratory pathway by oxygen.
authors.affiliation: Department of Biochemical and Pharmaceutical Technology, Faculty of Pharmacy, University of São Paulo, SP, Brazil.
authors.forename: D P
authors.initials: DP
authors.lastname: Silva
authors.forename: A
authors.initials: A
authors.lastname: Pessoa
authors.forename: I C
authors.initials: IC
authors.lastname: Roberto
authors.forename: M
authors.initials: M
authors.lastname: Vitolo
mesh_terms: D000388:Air; D001709:Biotechnology; D003470:Culture Media; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006593:Hexokinase / Q000096:biosynthesis*; D007700:Kinetics; D010100:Oxygen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000254:growth & development
chemical_list: D003470:Culture Media; D000431:Ethanol; D006593:Hexokinase; D005947:Glucose; D010100:Oxygen