Cultivation of Nannochloropsis algae for simultaneous biomass applications and carbon dioxide capture

Abstract

ABSTRACT Biological plants such as algae have a great potential of fixating CO2 from flue gases or atmospheric air and converting it into useful biomass. This is because CO2 is part of their photosynthesis process where the gas is an essential input ingredient. In this study, a closed system was designed for algae cultivation and carbon capture as a means to mitigate carbon emissions and at the same time assimilate biomass. Among species of saltwater microalgae there exist the Chlorella, Spirulina and Nannochloropsis among others. The latter was selected, as it is suitable for carbon capture because of its high carbon dioxide absorption characteristics, as well as its high oil content that is needed for the production of biofuel. To achieve this goal, the response of the algae was altered by generational mutations that were driven by environmental control of CO2 concentrations, pH level, and temperature, in addition to the sufficient supply of nutrients. Two flow rates, 2 L/min and 5 L/min were used for the biomass measurements and carbon dioxide capture analysis, resulting in CO2 removal efficiencies of 91.93%, and 65.43%, respectively. The benefit of the proposed system is twofold, first that it combines active carbon capture, which enhances algae growth. The algae is known to be able to thrive in harsh conditions of high temperature and high water salinity, which reflects favorably on the economy of the cultivation system as it does not require any expensive or energy intensive setups or treatments. This cultivation has a pronounced potential of biomass production that is left for a future study.