Polydiacetylene-based high-throughput screen for surfactin producing strains of Bacillus subtilis

PLoS One. 2014 Feb 3;9(2):e88207. doi: 10.1371/journal.pone.0088207. eCollection 2014.

Abstract

Although traditional mutation is still an attractive approach for strain improvement, it is tedious, time-consuming, and inefficient to screen for surfactin producing strains. To overcome this, we developed a high-throughput screening method for surfactin producing mutants by applying polydiacetylene (PDA) vesicles as sensors with visible chromatic change from blue to red, detected as colorimetric response (CR%) signal, which can even semi-quantify the yields of surfactin. Bacillus subtilis 723 was used as parent strain and multiply mutated with atmospheric and room temperature plasma (ARTP). Mutants were cultured in MicroFlask by Duetz (24 square deepwell plates, Applikon Biotechnology) and surfactin titers were tested in 96-well plates with PDA vesicles. Mutants with surfactin titers above150 mg/L (CR% value above 26%) were selected as high-yield strains and further quantified by HPLC. By integrating MicroFlask cultivation and the PDA vesicles detection, we screened 27,000 mutants and found 37 high-yield strains. From these, one mutant produced 473.6 mg/L surfactin (including 353.1 mg/L C15 surfactin), which was 5.4-fold than that of the parent strain. This method is efficient, cost-effective and provides wider application in screening for various surfactants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacillus subtilis / genetics*
  • Bacillus subtilis / growth & development
  • Bacillus subtilis / metabolism*
  • Bacterial Proteins / metabolism*
  • Biotechnology / methods
  • High-Throughput Screening Assays / methods*
  • Lipopeptides / biosynthesis*
  • Mass Spectrometry
  • Mutation / genetics*
  • Peptides, Cyclic / biosynthesis*
  • Polyacetylene Polymer
  • Polymers / chemistry*
  • Polyynes / chemistry*

Substances

  • Bacterial Proteins
  • Lipopeptides
  • Peptides, Cyclic
  • Polyacetylene Polymer
  • Polymers
  • surfactin peptide
  • Polyynes
  • polydiacetylene

Grants and funding

This work was supported by the National Basic Research Program of China (973 Plan) (Grant No. 2011CB710800), the National High Technology Research and Development Program of China (863 Plan) (No. 2012AA021700), National Science Foundation for Distinguished Young Scholars of China (No. 21225626). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.