Production of lipopeptides by Bacillus subtilis in solid status fermentation and their application in antifungal and heavy metal remove

Lipopeptides have many useful applications in antifungal activity, biomedical and pharmaceutical applications. Due to their unique structure, they have the potential to be a substitute for many antibiotics. At present, the main way to produce lipopeptides is at the laboratory level, and the yield is not very optimistic. In this study, under the premise of selecting agricultural and sideline products as fermentation substrates, the fermentation was carried out by Bacillus subtilis CCTCCM207209, and a series of conditions ranging from medium composition to fermentation conditions were optimized. Results revealed that the optimal conditions for maximum lipopeptides production and total antifungal activity were 3 g soybean flour, 2 g rice straw and 3g wheat bran as the solid substrate in 250ml erlenmeyer with initial pH 7.0, moisture content 60% and a 10% inoculum level at 32 °C for 5 days. Under these conditions, the experimental yield of lipopeptides reached 70.98 mg/gds and the total antifungal activity reached 659.03 U/gds. In addition, this study also found the application of lipopeptides in the removal of heavy metal ions. Under suitable conditions, it has excellent removal effect on heavy metal ions Cd2+ and Pb2+. Through this research, firstly, we can use cheaper agricultural by products to produce lipopeptides, and secondly, we can use the fermentation products to remove heavy metal pollution, which adds a new way for the removal of heavy metals.