Estimation of experimental data and kinetic modeling of the growth of microalgae Botryococcus braunii

• Grant number: 12/06812-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): August 01, 2013
• Effective date (End): July 31, 2014
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Rubens Maciel Filho
• Grantee: Luisa Helena Perez Nascimento
• Host Institution: Faculdade de Engenharia Química (FEQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Continued use of petroleum-sourced fuels is now widely recognized as unsustainable because of depleting supplies and the contribution of these fuels to the accumulation of carbon dioxide in the environment. Biodiesel from oil crops and bioethanol from sugarcane are being produced in increasing amounts as renewable biofuels, but their production in large quantities is not sustainable. Many microalgae are exceedingly rich in oil, which can be converted to biodiesel using existing technology. Producing microalgal biodiesel requires large quantities of algal biomass. Microalgae can be grown on a large scale in photobioreactors. Microalgal biodiesel has the potential to fully replace petroleum fuels, not adversely affecting the supply of food or other agricultural products. It is also demonstrated that microalgal biodiesel is a better alternative compare to bioethanol from sugar cane, which is currently the most used transport biofuel. The algal production yield is still quite low on industrial scale. "To become competitive, this production should be at least 100g per m2 per day, it means three times bigger than today". In this context, is important to obtain a culture medium and appropriate conditions in order to maximize the production of biomass. It is known that the microalgae B. braunii requires water, light, inorganic nutrients and CO2 and that it's productivity is affected by pH, pCO2, irradiation, salinity and temperature. Some culture media are described in literature as Chu-13 and Prat. Culture media considered alternative and feasible to improve the microbial growth with high oil content have been understudied. These considerations are important to enhance the cellular growth and lipids production for subsequent production of biodiesel. The main goal of this research is to obtain a maximized and economically feasible culture medium in order to produce biodiesel using microalgae Botryococcus braunii and investigate the microalgal behavior, through a kinetic model of growth, taking into account some studied parameters. The experiments will initially be conducted in erlenmeyer, using the modified Chu medium with a sodium bicarbonate supplement. In this step will be possible to obtain kinetic growth data and the best conditions for cultivation in a fermenter, in order to produce biomass rich in lipids. Later the experiments will be performed in an agitated airlift fotobioreactor using as inoculum the best result from the previous step. The culture medium at this stage will consist of seawater at different salinities, CO2 and light. A total of 29 experiments will be accomplished through an experimental design and a kinetic growth model will be developed or ajusted according to literature. (AU)