Bacillus subtilis, as a biocontrol bacterium, possess a variety of biological functions and the capacity to control plant pathogens. Iturin A is a biosurfactant with broad-spectrum antifungal activity produced by fermentation of B. subtilis. In this study, the dynamic parameters of solid-state fermentation (SSF) and submerged fermentation (SMF) of Bacillus velezensis ND were compared, and a method for producing iturin A with a yield of 12.46 g/kg utilizing SSF was proposed. It has significant advantages over SMF and has the highest yield of all previously reported studies. B. velezensis ND also contains protease activity, cellulase activity, iron-carrying activity, the ability to synthesis 3-indoleacetic acid (IAA), fixation nitrogen, and degrade phosphorus. In cotton pot experiments, it can effectively increase cotton growth and minimize Verticillium wilt. This strain's superior fermentation efficiency, biological function, and biocontrol ability are sufficient to demonstrate its promise for the development and use of biocontrol agents.
Keywords: Bacillus; biocontrol; biological function; fermentation; iturin A.
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