Abstract The biological assimilation of the sugars present in lignocellulosic residues has gained prominence since these residues are the most abundant and economic residues in nature. Thus, the objective of this work was to determine whether the use of D-xylose and L-arabinose as sources of carbon in Synechococcus nidulans and Spirulina paracas cultures affects the growth and production of proteins and carbohydrates. Kinetic growth parameters, pentose consumption, protein content and carbohydrates were evaluated. Synechococcus nidulans and Spirulina paracas consumed all concentrations of pentose used. The highest cellular concentration (1.37 g.L-1) and the highest protein productivity (54 mg.L-1.d-1) were obtained for Spirulina paracas, which was submitted to the addition of 38.33 mg.L-1 D-xylose and 1.79 mg.L-1 L-arabinose. The use of pentose promoted the accumulation of proteins for the studied microalgae. This is one of the first works to report protein bioaccumulation as a result of pentose addition.
ABSTRACT Spirulina is a microalgal genre that has the capacity to produce various bioproducts with applications in several areas including the energy sector. The study aimed to assess the ability of CO2 biofixation, biodiesel and other biocompounds production by Spirulina sp LEB 18 cultured in air-lift photobioreactor. The microalgae presented a rich macronutrient composition: protein (47.3%), carbohydrates (13.4%) and a high lipid content (32.7%) in a media with nitrogen reduction, CO2 using air-lift photobiorector. Furthermore, 160 mg.L.d-1 of CO2 was biofixed, generating a maximum biomass yield of 0.02 g.L.d-1. The lipids evaluated for biodiesel production presented a theoretical yield of 19.8% for in situ transesterification and 47.9% for conventional transesterification. The microalgal biomass has potential for producing biodiesel that can be applied instead or in mixture with traditional diesel fuel. The study of obtaining energy associated with the production of other high value-added biocompounds from the microalgal biomass is of high importance because in this way, the viability of biofuel production by this microorganism can be increased.