title: Squalene versus ergosterol formation using Saccharomyces cerevisiae: combined effect of oxygen supply, inoculum size, and fermentation time on yield and selectivity of the bioprocess.
abstract: The dynamics of two wild type strains of Saccharomyces cerevisiae (BY4741 and EGY48) that vary in the ability to produce sterols were compared in batch cultures under different aeration conditions. Poor supply of oxygen enhanced selectivity of the bioprocess in favor of squalene formation. Optimization of inoculum size and fermentation time arranged according to a central composite statistical design revealed significant differences between the strains in terms of yield and productivity. Experimental verification showed that an optimized bioprocess under semianaerobic conditions is competitive with regard to those reported in the literature. Maximum squalene yield and productivity were, respectively, 2967.6 +/- 118.7 microg/L of culture medium and 104 +/- 4.2 microg/Lh for BY4741 and 3129 +/- 109.5 microg/L of culture medium and 155.9 +/- 5.5 microg/Lh for EGY48. The prospect of developing high-purity squalene preparations that meet food safety regulation demands is expected to attract the interest of the food industry.
authors.affiliation: Laboratory of Food Chemistry and Technology, School of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Fani
authors.initials: F
authors.lastname: Mantzouridou
authors.forename: Eleni
authors.initials: E
authors.lastname: Naziri
authors.forename: Maria Z
authors.initials: MZ
authors.lastname: Tsimidou
mesh_terms: D000693:Anaerobiosis; D003470:Culture Media; D004875:Ergosterol / Q000378:metabolism*; D005285:Fermentation; D019649:Food Industry; D010100:Oxygen / Q000008:administration & dosage*; D012441:Saccharomyces cerevisiae / Q000254:growth & development / Q000378:metabolism*; D013185:Squalene / Q000378:metabolism*; D013997:Time Factors
chemical_list: D003470:Culture Media; D013185:Squalene; D010100:Oxygen; D004875:Ergosterol