title: Efficient production of sophorolipids by Starmerella bombicola using a corncob hydrolysate medium.
abstract: Sophorolipids (SLs) are amphiphilic compounds produced from a variety of saccharides and vegetable oils by the yeast Starmerella bombicola and related strains, and they have commercial uses as detergents. In the present study, SL production was investigated using a corncob hydrolysate (CCH) medium derived from lignocellulosic feedstocks as a source of hydrophilic carbon substrates. Excess sulfuric acid concentrations during pretreatment of the corncobs increased the furfural concentrations and turned the CCH dark brown. The optimal sulfuric acid concentration was 1% (w/v), and the treated CCH, containing 45 g/l glucose, allowed the production of 33.7 g/l of SLs following 4 days of cultivation. Additional autoclaving (121°C, 20 min) inhibited SL production and cell growth by 36% and 40%, respectively. Ammonium nitrate (0.1 g-N/l) restored SL production to the autoclaved CCH. Finally, a cost-effective SL production of 49.2 g/l, with a volumetric productivity of 12.3 g/l/day, was achieved using CCH medium during batch cultivation in a jar fermentor.
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan. Electronic address: konishim@mail.kitami-it.ac.jp.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Konishi
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yoshida
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Horiuchi
mesh_terms: D001203:Ascomycota / Q000187:drug effects* / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D019149:Bioreactors / Q000382:microbiology*; D003470:Culture Media / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D003902:Detergents / Q000737:chemistry / Q000378:metabolism; D005662:Furaldehyde / Q000378:metabolism; D006017:Glycolipids / Q000096:biosynthesis* / Q000737:chemistry; D006868:Hydrolysis; D057927:Hydrophobic and Hydrophilic Interactions; D008031:Lignin / Q000378:metabolism; D010938:Plant Oils / Q000378:metabolism / Q000494:pharmacology; D013464:Sulfuric Acids / Q000737:chemistry / Q000494:pharmacology; D003313:Zea mays / Q000737:chemistry* / Q000187:drug effects
chemical_list: D003470:Culture Media; D003902:Detergents; D006017:Glycolipids; D010938:Plant Oils; D013464:Sulfuric Acids; C036909:lignocellulose; D008031:Lignin; D005662:Furaldehyde; C033158:sulfuric acid
keywords: Biosurfactant; Corncob hydrolysate; Lignocellulosic biomass; Sophorolipids; Starmerella bombicola; Surface-active glycolipid