Optimization of Messastrum gracile cultivation in different light intensities in photo-autotrophic and mixotrophic schemes

Abstract

Evaluating the cost of traditional (photo-autotrophic) production with mixotrophic using alternative sources to reduce microalgae cultivation costs providing high biomass is a type of protocol that should be adopted in algal production. Therefore, evaluating factors such as light, culture medium, culture condition (photo-autotrophic and myxotrophic), carbon source and appropriate techniques for maintaining high Messastrum gracile biomass are procedures for process performance and balanced condition of the operation cultivation. Microalgae cultivation is an area that has stood out among the main researches developed in the world market, since these microorganisms synthesize several compounds of interest in different sectors. Optimizing and reducing production costs are key technologies for implementing successful microalgae cultivation. The use of alternative sources such as inorganic fertilizers (NPK), aquatic plants (Eichhornia crassipes) as a culture medium and sugarcane molasses (carbon source) are tools that enable the cultivation of microalgae. However, the cost of production is still very high due to the culture medium containing a diversity of macro and micronutrients, vitamins and minerals for the development of high algal biomass. One way to lower the cost of production is the use of alternative culture media, cultivation conditions using alternative carbon sources and the reduction of light intensity, which is one of the factors that most increases the cost of producing microalgae biomass. Light intensity is one of the major limiting factors in microalgae cultivation, affecting photosynthesis, biomass and biochemical composition. The use of biological residues and agribusiness by-products for microalgae cultivation, such as macrophytes and sugarcane molasses, are of great importance to reduce the negative impacts on both natural and/or artificial ecosystems (fish farming). (AU)