Comparative study on the properties of lipopeptide products and expression of biosynthetic genes from Bacillus amyloliquefaciens XZ-173 in liquid fermentation and solid-state fermentation

This study compared the compositions and properties of lipopeptide products purified from liquid fermentation (LF) and solid-state fermentation (SSF) and transcription levels involved in lipopeptides under the two systems. Results of Fourier transform infrared spectroscopy and High performance liquid chromatography revealed no significant differences in the polarity and structure of the two lipopeptide products. A higher amino acid proportion was found for lipopeptide product in LF than in SSF. Lipopeptide product produced from LF had better emulsification and antagonistic activities than that from SSF. For SSF, the transcription accumulation levels of the lipopeptide synthetic genes srfAA and sfp were higher than for LF at the same stage. Transcripts for ituD and lpa-14 remained elevated for a longer period of time under SSF conditions, accounting for differences in the production and fermentation periods between SSF and LF. This is the first report that describes differences in lipopeptide product synthesis and molecular behaviors between LF and SSF systems.