title: Proteomic analysis of Saccharomyces cerevisiae under high gravity fermentation conditions.
abstract: Saccharomyces cerevisiae KAY446 was utilized for ethanol production, with glucose concentrations ranging from 120 g/L (normal) to 300 g/L (high). Although grown in a high glucose environment, S. cerevisiae still retained the ability to produce ethanol with a high degree of glucose utilization. iTRAQ-mediated shotgun proteomics was applied to identify relative expression change of proteins under the different glucose conditions. A total of 413 proteins were identified from three replicate, independent LC-MS/MS runs. Unsurprisingly, many proteins in the glycolysis/gluconeogenesis pathway showed significant changes in expression level. Twenty five proteins involved in amino acid metabolism decreased their expression, while the expressions of 12 heat-shock related proteins were also identified. Under high glucose conditions, ethanol was produced as a major product. However, the assimilation of glucose as well as a number of byproducts was also enhanced. Therefore, to optimize the ethanol production under very high gravity conditions, a number of pathways will need to be deactivated, while still maintaining the correct cellular redox or osmotic state. Proteomics is demonstrated here as a tool to aid in this forward metabolic engineering.
authors.affiliation: Biological and Environmental Systems Group, Department of Chemical and Process Engineering, The University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK.
authors.forename: Trong Khoa
authors.initials: TK
authors.lastname: Pham
authors.forename: Poh Kuan
authors.initials: PK
authors.lastname: Chong
authors.forename: Chee Sian
authors.initials: CS
authors.lastname: Gan
authors.forename: Phillip C
authors.initials: PC
authors.lastname: Wright
mesh_terms: D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D020869:Gene Expression Profiling; D005947:Glucose; D006019:Glycolysis / Q000235:genetics*; D018471:Hypergravity; D013058:Mass Spectrometry; D040901:Proteomics; D012441:Saccharomyces cerevisiae
chemical_list: D005656:Fungal Proteins; D000431:Ethanol; D005947:Glucose