A promising lipopeptide production and application as biostimulant for seeds germinations

Global agricultural systems face increasing challenges related to food insecurity, environmental degradation, and the intensive use of synthetic agrochemicals, emphasizing the need for sustainable alternatives aligned with circular bioeconomy principles. In this context, this study aimed to produce, characterize, and evaluate the biostimulant activity of a fungal lipopeptide biosurfactant produced by Absidia cylindrospora var. cylindrospora UCP 1301 using low-cost agro-industrial by-products. Biosurfactant production was conducted by submerged fermentation with crude glycerol and corn steep liquor, optimized through a 2³ full factorial design, followed by ethanol-assisted recovery and physicochemical characterization. Under optimized conditions, the biosurfactant reduced surface tension from 72.0 to 28.3 mN m⁻¹, exhibited a critical micelle concentration of 90 mg L⁻¹, a negative zeta potential of −76.3 mV, and maintained surface activity over a wide range of pH, salinity, and temperature conditions. In seed bioassays, Lactuca sativa presented a maximum germination index of 146.5% at 25% of the CMC, with a relative root elongation of 146.8%, while Zea mays seedlings showed radicle length increases of up to 142.9% compared to the control. These findings indicate that the lipopeptide biosurfactant produced by A. cylindrospora var. cylindrospora UCP 1301 exhibits physicochemical stability and biostimulant activity, supporting its applicability as a bioinoculant for sustainable agricultural systems.