Avaliação da produção de ficocianina a partir do cultivo mixotrófico de synechococcus nidulans utilizando água de viveiro de camarões e melaço de cana-de-açúcar

Abstract

The shrimp farming activity refers to shrimp farming and is very significant in the Northeast region of Brazil. To ensure the functioning of farms, a large amount of water is necessary and, in case of inadequate disposal, it can cause environmental damage. Another prominent activity in the country is the cultivation of sugar cane, which generates several by-products. One of them is molasses, whose sugar and nutrient levels are quite high. On the other hand, the use of microalgae to aid in the treatment of wastewater linked to the biorefinery process has been gaining prominence. Studies show that sugarcane molasses can be used as a low-cost and efficient supplement to microalgae growing media, offering substantial amounts of organic carbon. The present study sought to evaluate the potential for reusing water from the organic shrimp production pond to dilute the Zarrouk medium (50%, 60%, and 70%) and the effect of adding molasses, compared with the traditional Zarrouk medium for shrimp cultivation. cyanobacterium Synechococcus nidulans. Low-cost cultivation media can enable the production of microalgae on large scales in an optimized way. Furthermore, we sought to extract phycocyanin, a natural pigment present in microalgae of the genus Synechococcus. Cultivations were carried out under autotrophic and mixotrophic conditions, with a 12-hour light/dark photoperiod at 25°C and mechanical air aeration. The Zarrouk 70% SM (Without Molasses) and CM (With Molasses) cultivations generally showed better results compared to the other conditions, with biomass concentrations of 0.97 g L-1 in both tests, but with lower results concerning the traditional Zarrouk. It was found that the addition of molasses to the medium did not significantly interfere in favoring greater biomass production. Biomass was characterized by carbohydrates, lipids, crude protein, and carotenoids. Carbohydrates were favored by the addition of molasses and the 70% CM test reached a maximum percentage of 21.24 ± 3.49%, as well as the lipid content, which presented maximum values of 1.80 ± 0.69% (70% SM) and 6.60 ± 1.35% (70% CM). The protein content, in turn, was not affected, with maximum values reached of 20.27 ± 3.52% (70% SM) and 19.37 ± 0.56% (70% SM). Regarding the carotenoid content, a slight increase in concentration was observed in the mixotrophic experiments, with the highestvalue of 40.70 ± 4.09 mg g-1 (60% CM). The production of phycocyanin was also favored andextracted, with a concentration of 1.49 ± 0.29 mg mL-1 in the 70% CM assay, with an Extract Purity of 0.29.