Laboratory apparatus to evaluate microalgae production

Abstract

-The application of microalgae for energy purposes and CO 2 biomitigation continues to present a number of challenges, including the optimization of culture conditions. The application of experimental designs for microalgae cultivation is difficult, since experiments involving such microorganisms generally last days or weeks. This work proposes a multipurpose laboratory apparatus for the optimization of microalgae experimental conditions that simultaneously enables the evaluation of variables such as temperature, irradiance, photoperiod and CO 2 concentration in the aeration stream, as well as variables related to the concentration of culture media nutrients. A case study is also presented in which temperature, concentration of f/2 medium sodium nitrate and the effects of incident light intensity on Nannochloropsis oculata lipid content are evaluated. Experiments were carried out following central composite designs, in batch cultivation within an airlift photobioreactor apparatus. The best experimental result was obtained at 21 °C, 119 mg/L NaNO 3 and 137 µE.m -2 .s -1 , corresponding to 41.8% lipids and 211.9 mg.L -1 final lipid concentrations.

Potential biodiesel production from four green microalgae cultures collected off the Lebanese coast

“…This was reflected in the level of biomass produced which ranged from 406 to 495 mg dry weight (DW)/L of culture medium/harvest every 8-10 days. This level of production is of the same order of magnitude reported in many recent publications [14,16,17] following optimization of growth conditions. However, the biomass yield of the Lebanese isolates is considerably less than those reported by [3], where the maximum dry matter yield reached about 300 mg/L/day.…”

“…For biodiesel production a high content of saturated and mono unsaturated fatty acid is preferred to get a good quality biodiesel, three out of the four isolates tested may fit this specification especially in the stationary phase where biomass production is highest. The lipid content of microalgae and the composition of their saturated and unsaturated fatty acids may be affected by several factors including the light conditions, nutrient composition of the medium, pH, salinity and mainly nitrogen starvation [14]. Therefore, optimization of culturing conditions may improve the total biomass production and/or the total lipid content.…”

Novo Método Para a Quantificação Rápida De Lipidios Em Microalgas

“…Foram montados sete fotobiorreatores air-lift de aproximadamente 3 litros cada (para maiores informações ver o trabalho de Gris et al, 2013). Os fotobiorreatores foram mantidos à temperatura de 20°C, temperatura recomendada por Xin et al (2011) para obtenção de maior conteúdo de lipídios.…”

Growth of microalgae Scenedesmus sp in ethanol vinasse

“…To avoid the loss of culture medium by evaporation, a flask on the photobioreactor lid was added, which allowed the evaporated liquid to condense. A silicone lid covered the orifice sampling to prevent the evaporation (a detailed description of the laboratory apparatus can be obtained in the work of Gris et al (2013)). …”