Kinetic and Stoichiometric Relationships of the Energy and Carbon Metabolism in the Culture of Microalgae

Abstract

Some microalgae can grow metabolizing inorganic and organic carbon sources, which might occur simultaneously and independently, while energy is supplied by light and/or an organic carbon source. In this context, the contribution of each metabolism to total growth can be determined by quantitative analysis. The illumination of microalgal cells growing in the presence of organic substances, might cause an effect which can drive the carbon metabolism in different ways. When analyzing the growth of different strains of microalgae, some differences could be distinguished , between additive or inhibitory effect of light on heterotrophi c metabolism in mixotrophic or photoheterotrophic growth. This manuscript proposes, the integration of a kinetic and stoichiometric metabolic model which explains the differences of carbon and energy utilization modes between mixotrophic and photoheterotrophic growth in microalgae. This model presumably discloses relevant independent facts between the mechanisms of photosynthesi s and the oxidative metabolism of organi c compounds, such as glucose and the importance of these differences on the production of biomass and secondary metabolites.