EVALUATION OF MICRO-ALGAE GROWTH Messastrum gracile IN COMMERCIAL AND ALTERNATIVE CULTURE MEDIA USING SUGAR CANE MOLASS IN LESS LIGHT LENGTH

Abstract

The cultivation of microalgae promotes several studies to propose better management in production and cost reduction, since the implantation of these systems is high due to the need for light and culture media of high commercial value. Optimize and reduce costs through alternative means based on aquatic plants (Eichhornia crassipes), organic carbon source (sugar cane molasses) and reduced energy use are essential tools for implementing a successful algal culture. Thus, the objective of this work was to evaluate the development of Messastrum gracile microalgae in commercial medium CHU12 in mixotrophic cultivation using sugarcane molasses as a carbon source and an alternative macrophyte medium (E. crassipes), in luminous intensity of 30umol m-2 s-1. The highest growth values were observed in the macrophyte medium with maximum cell density of 197 x105 cells mL-1 and in the commercial medium, with 95x105 cells mL-1. The specific growth rate was k = 0.41 (macrophyte) and k = 0.27 (CHU12), with faster doubling time in the alternative medium with 2.45 days, whereas in the commercial medium it was 3.70 days. The levels of chlorophyll-a were 1.15 mgL-1 for E. crassipes and for CHU12 0.66 mgL-¹ was determined. The use of biological waste and a by-product of the agribusiness to produce these microorganisms is short importance to reduce the negative impacts on ecosystems.