Produção de biomoléculas por Fusarium sp utilizando a casca do caule do cajueiro Anacardium occidentale L

Abstract

The growing concern over the environmental impacts caused by synthetic surfactants has driven the development of microbial biosurfactants and bioemulsifiers in the pursuit of sustainable processes and the valorization of waste materials (chemical, agro-industrial, and oily residues) discarded into the environment. This study aimed to investigate the biotechnological potential of Fusarium sp., using cashew tree stem bark (Anacardium occidentale L.) and oily residues post-frying oil (Experiments 1 and 2) and used motor oil (Experiment 3) as substrates, and to develop a viable and eco-sustainable bioprocess, with initial pH measured. The experiments were conducted at the Research and Extension Center for Food (NUPEA), at the State University of Paraíba (UEPB). Three fermentation experiments were carried out in 250 mL Erlenmeyer flasks containing 100 mL of the culture medium mentioned above, following a full factorial 2² design, agitated at 150 rpm for 168 hours (Experiment 1) and 96 hours (Experiments 2 and 3). The fungus was inoculated at 10⁷ cells/mL, with pH measured after the process. The response variables were Surface Tension (ST, mN/m) and Emulsification Index (EI₄, %). At the end of cultivation, the metabolic liquids were separated from the biomass by centrifugation at 10,000 rpm for 15 minutes and filtered (120 mesh). The cell-free metabolic liquid from Experiments 1, 2, and 3 showed no significant changes in final pH. ST values were: 69.24 mN/m (condition 3), 71.43 mN/m (condition 1), and 72.49 mN/m (condition 6), indicating unsatisfactory results. EI₄ (%) was satisfactory in all experiments, with the best result obtained in condition 6 of Experiment 3, reaching 90.91%, forming water-in-oil emulsions. The emulsions remained stable across all tests. Under the best condition, antimicrobial activity was assessed by well diffusion against phytopathogenic fungi, with inhibition halos of 5.0 cm and 2.1 cm in radius observed for Cladosporium cladosporioides and Claviceps purpurea, respectively. These results confirm the biotechnological potential of Fusarium sp. for the production of biomolecules with emulsifying and antifungal activity, with potential applications in natural pharmacological formulations. This strengthens the use of waste as raw material in accordance with the principles of the circular economy, making the process technically feasible and environmentally strategic.