A novel high-throughput and quantitative method based on visible color shifts for screening Bacillus subtilis THY-15 for surfactin production. (1st August 2015)

• Record Type: Journal Article
• Authors: Yang, Huan; Yu, Huimin; Shen, Zhongyao
• Is Part Of: Journal of industrial microbiology & biotechnology. Volume 42:Number 8(2015)
• Page Start: 1139
• Page End: 1147
• Publication Date: 2015-08-01
• Subjects: CPC–BTB screening method -- Chromatic responses -- Surfactin -- Bacillus subtilis -- MALDI-TOF MS/MS; Industrial microbiology -- Periodicals; 660.62
• DOI: 10.1007/s10295-015-1635-4
• Languages: English
• ISSNs: 1367-5435

Abstract

Abstract: A novel chromatic visible screening method using bromothymol blue (BTB) as a color indicator and cetylpyridinium chloride (CPC) as a mediator was constructed to obtain the high titer surfactin-producing strains. The reliability and quantification accuracy of color shift were also confirmed. Regular chromatic responses from faint yellow-green to dark green and bright blue reflected the different ranges of surfactin concentrations. Moreover, the quantitative accuracy of surfactin quantification in the range of 100–500 mg/L was verified by reverse-phase high-performance liquid chromatography (RP-HPLC) using different fermentation supernatant samples. Using this CPC–BTB method, a superior surfactin producer, Bacillus subtilis THY-15, was successfully screened. The producer's surfactin (Srf) titer reached 1240 mg/L. RP-HPLC analysis of THY-15 revealed four surfactin isoforms. As identified by amino acid analysis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, the isoforms of surfactin in fraction 1, 2 and 4 had the same circular peptide sequence of Glu-Leu-Leu-Val-Asp-Leu-Leu but different iso-C13, C14 and C15 fatty acid chains, but the isoform in fraction 3 possessed a special peptide sequence of Glu-Val-Leu-Leu-Asp-Leu-Val.