title: [Identification of Bacillus subtilis THY-7 and high titer optimization for the blend-biosurfactant of lipopeptide and glycolipid].
abstract: Biosurfactants (BSs) are highlighted owing to their multiple advantages in diverse applications. To screen a superior strain that producing a blend-biosurfactant of lipopeptide and glycolipid, the hemolytic activity assay on blood agar plates, the modified oil-red spreading test and MALDI-TOF Mass Spectrometry identification of the purified products was carried out. Bacillus subtilis THY-7 was selected and its principal products were surfactin and dirhamnolipid. The medium component and culture conditions of THY-7 were optimized by both single factor and orthogonal experiments. After 48 h optimal batch culture in flask, the cell density (OD600) was 37.0 and the product titer was 2.4 g/L, which was 3.4 folds and 3.1 folds of that under original condition, respectively. A fed-batch culture in a 5 L fermentor was further performed coupling with in situ recovery of foam, in which the titer of blend-BS increased to 4.5 g/L at 25 h. Quantification by HPLC and anthrone colorimetry revealed that surfactin and dirhamnolipid accounted for 74% and 22% of the blend-BS, respectively.
authors.forename: Hao
authors.initials: H
authors.lastname: Liu
authors.forename: Huan
authors.initials: H
authors.lastname: Yang
authors.forename: Xue
authors.initials: X
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.forename: Mian
authors.initials: M
authors.lastname: Duanmu
authors.forename: Huimin
authors.initials: H
authors.lastname: Yu
mesh_terms: D001412:Bacillus subtilis / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D006017:Glycolipids / Q000096:biosynthesis*; D007218:Industrial Microbiology; D055666:Lipopeptides / Q000096:biosynthesis*; D013501:Surface-Active Agents / Q000378:metabolism*
chemical_list: D003470:Culture Media; D006017:Glycolipids; D055666:Lipopeptides; D013501:Surface-Active Agents; C418382:rhamnolipid