Evaluation of CO2 Biofixation and Biodiesel Production by Spirulina (Arthospira) Cultivated In Air-Lift Photobioreactor

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.

Effect of Spirulina addition on the physicochemical and structural properties of extruded snacks

Abstract Nowadays the demand for practical food like snacks increases worldwide, however the nutritional value in most these formulations is reduced. Due to its chemical composition with high protein concentration, the microalga Spirulina has been used on the production of enriched foods. The present study aimed to evaluate the effects of Spirulina sp. LEB 18 addition on snacks formulations and extrusion conditions on the physicochemical and structural properties of snacks. Protein concentration and physical properties such as expansion index, bulk density, hardness, water absorption index, water solubility index and color were determined. The results showed that the addition of Spirulina sp. LEB 18, temperature in the last zone of the extruder and feed moisture influenced the product responses. The increase in feed moisture increased the hardness, bulk density and water absorption index of the snacks. Higher concentrations of microalga produced snacks with higher protein content, total color difference (ΔE) and compact structure. The addition of 2.6% Spirulina produced snacks with up to 11.3% protein and with adequate physical and structural properties for consumption. Thus, snacks containing Spirulina are an alternative to the demand for healthy food of practical consumption.

Perfil de ácidos graxos de microalgas cultivadas com dióxido de carbono / Fatty acids profile of microalgae cultived with carbon dioxide

As microalgas são consideradas fontes potenciais de diversos compostos químicos. Os ácidos graxos obtidos da biomassa podem apresentar efeitos terapêuticos em humanos e podem ser usados para produção de biodiesel. Objetivou-se, neste trabalho verificar o conteúdo lipídico e o perfil dos ácidos graxos das microalgas Spirulina sp., Scenedesmus obliquus, Chlorella kessleri e Chlorella vulgaris cultivadas em diferentes concentrações de dióxido de carbono e bicarbonato de sódio. A microalga Chlorella kessleri cultivada com 12 por cento de CO2 apresentou a maior concentração de lipídios na biomassa seca (9,7 por cento p/p). A máxima concentração de ácidos graxos insaturados foi 72,0 por cento (p/p) para C. vulgaris cultivada com 12 por cento de CO2. Para os ácidos graxos saturados o maior valor encontrado foi 81,6 por cento (p/p), quando a microalga Spirulina sp. foi cultivada com 18 por cento de CO2 e 16,8 g.L-1 de bicarbonato de sódio.

Microalgae have a great potential as a source of several chemical compounds. The fatty acids have shown therapeutic effects and used to produce biodiesel. The aim of this work was to verify the lipid contents and the fatty acids profile of the microalga Spirulina sp., Scenedesmus obliquus, Chlorella kessleri and Chlorella vulgaris cultived in different carbon dioxide and sodium bicarbonate concentrations. The microalgae Chlorella kessleri cultived with 12 percent CO2 showed the highest lipid content in the dry biomass (9.7 percent p/p). The maximum unsaturated fatty acids concentration was 72.0 percent (p/p) to C. vulgaris in the culture with 12 percent CO2. The highest saturated fatty acids value was 81.6 percent (p/p) when microalga Spirulina sp. was cultived with 18 percent CO2 and 16.8 g.L-1 sodium bicarbonate.