Carbon Metabolism Modification in <i>Bacillus subtilis</i> for Improving Fengycin Production and Investigating Antifungal Activity of Its Homologous Components

As a lipopeptide, fengycin exhibits environmentally friendly, safe, and long-lasting biocontrol efficacy. However, due to its complex structure and the challenges in chemical synthesis, it is primarily produced through biosynthesis. This study reports an improvement in fengycin production in <i>Bacillus subtilis</i> by engineering the central carbon metabolic pathway and blocking the carbon overflow pathway. The highest production achieved 1290.31 mg/L, representing a 2.05-fold increase compared to the original strain. Additionally, a coculture system was established in which <i>Corynebacterium glutamicum</i> supplied proline to strain CGF-PA, achieving a further increase in production to 2491.97 mg/L. The fengycin homologues were characterized using IMS-MS and separated by preparative liquid chromatography. The antifungal activities of fengycin homologues were quantitatively evaluated against <i>Fusarium graminearum</i>, <i>Botrytis cinerea</i>, <i>Pyricularia oryzae</i>, and <i>Rhizoctonia solani</i>, and their morphological changes were observed. The study also investigated the differences in antifungal activity among the fengycin variants. Components 4, 5, 6, and 7 exhibited relatively strong antifungal activity, and the various components of fengycin were found to work synergistically.