Sugar Cane Vinasse as a Renewable and Sustainable Feedstock for Lipid Production from Aspergillus Niger and Aspergillus flavus

Abstract

Background and Aims: In the search for sustainability and the use of renewable energies, biodiesel has stood out as a notable alternative to the growing energy demand of modern society. Microbial fat synthesis for lipids has been a possibility to produce this biofuel. In this context, the research work aimed to cultivate Aspergillus niger and Aspergillus flavus fungi in commercial and homemade broth, plus variable concentrations of sugarcane vinasse as a substrate to extract lipids produced using different extraction techniques and solvents. Methodology: The fungi were grown in a commercial medium and a homemade one made with potato extract. After cultivation, they were submitted to two pre-treatments: the Bead Mill technique and the Ultrasound technique. The extraction of lipids produced in a commercial medium was performed via Soxhlet with a mixture of solvents. Therefore, the lipids produced in a homemade medium were extracted with the adapted Bligh-Dyer method. Results: The species grew to the different culture media submitted, but the home culture medium increased the reproductive. The industrial residue proves to be a good alternative as a supplement to the culture medium, helping to reduce costs and preserve the environment. The extraction by Soxhlet showed satisfactory results when the fungi were grown in a commercial medium, with Aspergillus niger being extracted from the ethyl acetate solvent, obtaining a yield of 18.78%, and for A. flavus extracted with dichloromethane/methanol (9:1) and chloroform, bringing yield of 32.98% and 32%, respectively. Although extraction by Soxhlet showed some excellent results, extraction with the Bligh-Dyer method demonstrated better lipid fractions ranging from 25% to 67% and reduced energy expenditure, indicating a promising use, cost, and benefit. Conclusion: Filamentous fungi of the genus Aspergillus can be used to produce biodiesel as they proliferate and can produce the same amount of lipids as a vegetable, which requires a much larger area of soil, for example.