Bioprospecção de microalgas para aplicação biotecnológica

Abstract

Microalgae have been considered potential sources of biotechnological applications, due to their biodiversity, in addition to having a high concentration of carbohydrates, lipids, proteins and biomolecules in their biomass, such as antioxidants. They can be used in the areas of human and animal nutrition, pharmaceutical industry, water treatment, energy production, among others. In this study, the main objective was to bioprospect, select, characterize and evaluate the performance of microalgae from fish ponds for biotechnological application. Subsequently, the microalgae Chlorella sorokiniana was cultivated and its nutritional properties were characterized in a N:P:K (20:05:20) culture medium enriched with sugarcane vinasse. The efficiency of algal biomass flocculation was also performed using organic and synthetic polymers (polymers) to recover the biomass of the microalgae C. sorokiniana. Finally, the biomass yield and production of secondary metabolites by C. sorokiniana cultivated in commercial medium (Sueoka) and those cultivated in medium prepared with sugarcane vinasse (0.1%) supplemented with N:P:K were evaluated (20-5-20 gL-1). Chlorophyte microalgae (Chlorophyta), including the microalgae Chlorella sp. showed greater constancy in cell density during the 28-day period of culture. The biomass of the microalgae C. sorokiniana showed high protein concentration (58%), followed by carbohydrates (16.14%) and lipids (14.97%). In the elemental composition, the macronutrient that presented a high amount was iron (Fe), with a value of 882.6 mg k-1. In the algal biomass recovery test, the polymer with the highest flocculation efficiency was the Moringa oleifera seed with 100% recovery. The other polymers showed 97.17% recovery for PraestolTM, 95.28% for Tanfloc MT, 80.38% for chitosan. Mean levels of phenolic compounds and flavonoid content were found in the biomass of the microalgae C. sorokiniana cultivated in NPK medium and vinasse (15.28 ± 0.32 mg GAE.g-1 and 72.30 ± 5.28 mg QE.g-1, respectively) compared to the commercial medium (6.02 ± 0.13 mg GAE.g-1 and 13.12 ± 1.33 mg QE.g-1, respectively). Thus, we can infer that the microalgae C. sorokiniana can be used in the most diverse biotechnological areas, given its nutritional properties, easy availability and low cost of obtaining and maintaining.