Production of Dunaniella sp. rich in bioproducts from waste and effluent from super-intensive shrimp production

Abstract

Microalgae are rich in several bioactive biochemical compounds, which make them a great nutritional source for aquaculture and inputs for fine chemistry. Currently, the genus Dunaliella sp. is one of the world's main sources of natural carotenoids, having one of the highest concentrations of beta-carotene in its composition. This carotenoid is estimated to hold the largest share of the global market share of natural carotenoids in 2021, with around 26%. This carotenoid, in addition to having high added value, also has nutraceutical effects on shrimp and other aquatic organisms, when incorporated as an additive or ingredient in the feed. However, the national aquaculture market, especially shrimp farming, still does not have national products with microalgae that have the benefits provided by the expected product of this project. Being the benefits, the promotion of resistance to microbial diseases, such as the white spot syndrome virus and vibrios, antioxidant action and gain of a more reddish color to the shrimp meat, something desired by the final consumer. This lack of products based on microalgae in the Brazilian sector occurs for several reasons, among the main ones is the high cost of production, with emphasis on the culture medium, whose cost is proportional to the scaling. The traditional culture medium demands a series of chemical inputs, the main elements being nitrogen, phosphorus and trace metals. The search for substitutes for the vital nutrients, microalgae, nitrogen and phosphorus, to make production cheaper is one of the alternatives sought by the algal sector. In this way, the formulation of culture media with residues from shrimp production becomes a strong option from an economic and sustainable point of view for microalgal cultivation in scale. The present project will seek to evaluate the technical feasibility and improvement of the cultivation process of Dunaliella salina microalgae using shrimp residues as a culture medium, aiming to obtain an important reduction both in production costs and in the environmental impact caused by this type of activity. The main purpose is to generate a dry biomass rich in beta-carotene for use as an animal feed additive based on D. salina or as an input for fine chemistry. Therefore, a physical-chemical pre-treatment approach will be used, consisting of drying, filtration and characterization of waste and effluents. Then, the cultivation with formulations of the culture medium containing the residues will be carried out and, finally, the characterization of the microalgal biomass after the downstream. The aim is to obtain a dry biomass with levels of 7% of beta-carotene and a reduction in the cost of the culture medium of at least 40% when compared to the synthetic medium. With this, it is expected to achieve a product of quality equivalent to the international market and with greater competitiveness, due to lower production and logistics costs in the carotenoid sector, in addition to the development of an innovative product from microalgae nationwide in the aquaculture market. (AU)