Biomass production by Aphanothece microscopica and Chlorella vulgaris in heterotrophic growth from glucose

Abstract

Microalgae and cyanobacteria are preferentially photosynthetic microorganisms, however some strains can to develop in the dark by the consumption of simple organic molecules, such as glucose, acetate and glycerol. In these systems, known as mixotrophic and heterotrophic, glucose is the most commonly used carbon source. There is little information in the literature about the carbon source concentration required for optimal metabolic growth. Thus, this study aimed to explore the heterotrophic cultivation of cyanobacteria Aphanothece microsopica Nägeli and chlorophyceae microalgae Chlorella vulgaris Beyerink from glucose, in order to apply the versatile metabolism of these microorganisms in the agro-industrial wastewater treatment. Experiments were set up initially in the culture medium with different glucose concentrations in mixotrophic systems. In the best condition for growth (12.5 and 25 g L-1 for C. vulgaris and A. microscopica, respectively) were evaluated the typically heterotrophic cultivation system, resulting in maximum specific growth rate of 0.09 and 0.089 h-1 and glucose removal of 30.4% and 42% by the Cyanobacteria and Chlorophyceae, respectively. The results demonstrated the possibility of cultivation of both species under heterotrophic cultures.