Exploration of production of C14 and C15 bacillomycin D homologues with enzymatic hydrolysis from maize straws using fed-batch fermentation by Bacillus subtilis NS-174

Abstract

A strain with strong antifungal activity, Bacillus subtilis NS-174, was identified and the antifungal compounds were purified and structurally analyzed by high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS). The effects of the enzymatic hydrolysis and the fermentation strategies on production of the antifungal compounds were also investigated. The results showed that the antifungal compounds were characterized to be C₁₄ and C₁₅ bacillomycin D homologues (C_14–15BDs). When 400 mL of the cellulase hydrolysates from the maize straws residues (CHMSRs) was fed into 1.0 L of the batch fermentation broth at 60 h, an output of C_14–15BDs (OC_14–15BDs) was obtained as 44.84 mg g_{maize straws}⁻¹. Moreover, the fed-batch fermentation was beneficial for the increase of the transcriptional activities of C_14–15BDs synthetase genes by up-regulating expression of comA, sigmaH and spo0A, which caused the elevation of C_14–15BDs production. The present work provided an effective solution for lipopeptide production in Bacillus subtilis.