Monitoring the CO2 consumption of Monoraphidium sp. microalgae: Characterization of algal biomass produced

Resumen

Microalgae are unicellular organisms capable of photosynthesis, turning sunlight and carbon dioxide (CO2) into rich biomass, precisely because of this definition in recent years, various sectors have been targeting the ability to reduce CO2 emissions and the capacity of simultaneously synthesize biomass which can later be used to produce bio-fuels. In respect to the capturing and utilization of CO2 emitted by different industries (cement, generation of electric energy, cellulose and ethanol production by fermentation of sugars) for the cultivation of microalgae destined to the production of bio-fuels, for example, biodiesel, ethanol or bio-oil. However, this research was developed in the Green Technologies Laboratory - Greentec / EQ / UFRJ, which focussed on the monitoring of CO2 consumption in microalgae Monoraphidium sp. cultivated in closed-window type photobioreactor, as well as, the characterization of the microalgal biomass produced in relation to the total lipid content (TL), convertible lipids into biodiesel (CLB), carbohydrates and proteins.The overall procedure involved the evaluation of the following parameters: injection of CO2, temperature (°C), lighting (μE m-2 s-1), pH, cell density (cells ml-1) and dry biomass. From the results of this study, it was observed that at the beginning of the culture (day 0) 0.79 g of CO2 were consumed per each gram of biomass produced. On the last day (12), 0.3 g of CO2 were consumed per gram of culture. On the sixth day of cultivation, the consumption of CO2 per gram of biomass increased, resulting in a CO2 consumption of 0.61 g. The best result was obtained on the second day of cultivation, when for each gram of biomass produced approximately 1.2 grams of CO2 were consumed. The biomass Monoraphidium sp. produced, contained 17,37 ± 3,27% of total lipid content, approximately 8.36 ± 2.69% of convertible lipids into biodiesel, 32% ± 3.37 of carbohydrates and 34.26% ± 0.41 of protein. The analysis performed by -GC-MS Gas chromatography showed the following composition of saturated fatty acids (SAFAs) mainly the C16:0 (palmitic), as in monounsaturated acids (MUFAs), in high quantity C18:1 (oleic) and polyunsaturated acids (PUFAs) mainly represented by C18:2 (Linoleic) and C18:3 (linolenic).