Bioconversion of sugarcane vinasse into fungal biomass protein and its potential use in fish farming

Abstract

The intensification of pisciculture operation requires the provision of an adequate supply of good quality fish feed. Many commercial feeds consist in fishmeal or soybean meal-based formulations, but they constitute costly protein sources. Hence, dietary transition from conventional fish ingredients towards fungi protein sources produced from vinasse could address concern about both fish feed cost and the detrimental environmental effects of distillery waste disposal. This work investigated the nutritional and toxicological aspects of Aspergillus sp. V2 grown on vinasse to be used as a possible fish feed. Proximate analysis of biomass obtained from 50% (v/v) residue supplemented with 2.0 g/L (NH4)2H2PO4 revealed a total proteins content (34.0%), fat (4.7%), ash (15.8%), crude fiber (4.0%), moisture (0.3%) and carbohydrate (45.2%) within acceptable levels for commercial fish diets. The biomass protein composition was similar to soybean meal, containing all the essential amino acids (EAAs) for fish feeding. Finally, total aflatoxins level was 6.8 ± 0.2 µg per kg of dry weight, which does not exceed the permissible levels established for feedstuffs. These findings provide evidence that biomass of Aspergillus sp. V2 produced from vinasse could meet the nutritional requirements for use in fish diet, reducing economic pressures for the pisciculture and distilleries.