Vitamin B3 with action on biological oxide/reduction reactions and growth biostimulant in Chlorella vulgaris cultivation

Abstract

Niacin and niacinamide are water-soluble vitamins of the B group, influence the formation of the coenzymes NAD+/ NADH and NADP+/ NADPH, and play an important role in growth and development and redox potential. The present study aimed to evaluate the physicochemical properties of the culture medium from agricultural effluent and growth and CO2 biofixation of Chlorella vulgaris with vitamin supplementation. The supplementation with B3 (niacinamide e niacin) vitamins (200 mg/L) in the culture medium was evaluated, being: control (no supplementation), in physiological active form (niacinamide 200 mg/L), acid form (niacin 200 mg/L), and niacinamide 100 mg/L + niacin 100 mg/L. The multivariate model used to evaluate the growth parameters of Chlorella vulgaris and the physicochemical properties in cultivation in a photobioreactor identified the positive dependence of pH, cell concentration, and biomass with vitamin supplementation, occurring the opposite for ORP. The B-complex vitamins (B3) showed a biostimulant effect on growth and consequently increased the CO2 biosynthesis capacity of Chlorella vulgaris. The vitamin provides a culture medium with lower oxidative stress and ORP. The reapplication of the vitamin caused a new stimulus in the growth of the microalgae and changes in the physicochemical parameters of the culture medium, being the increase in pH and the decrease in ORP because the duration of the effect of the vitamin occurs for a short period. Vitamin supplementation achieved a peak productivity (g/L/day) of Chlorella vulgaris biomass of 0.2564/L/day. Cell morphology analysis showed a larger cell size in the presence of vitamin B3. Niacinamide and/or niacin is a growth biostimulant and reduces the oxidative stress of the Chlorella vulgaris culture medium.