Effects of monoethanolamine concentration on biomass productivity, CO2 fixation and biodiesel productivity of chlorella SP, and thalassiosira SP using a flask-flat plate photobioreactor

Microalgae as a source of biodiesel have been a favorite topic in the field of renewable energy. Though it has the advantage of CO2 consumption, quick production rate and high oil content, it is yet to become the mainstream source of biodiesel because of insufficient knowledge on optimizing large scale algae production. Chlorella sp. and Thalassiosira sp. were grown in a flask-flat plate bioreactor using fresh and used monoethanolamine (MEA) with concentration ranging from 0 to 300 ppm. The effect on the biomass conentration of the Chlorella sp. strain was analyzed using a spectrophotometer while the Thalassiosira sp. was analyzed using dry weight analysis. FAME profile was tested with the use of the Clarus-500 Gas Chromatography equipment. It was observed that for both Chlorella sp. and Thalassiosira sp., simultaneous operation using fresh MEA solution proved to be beneficial. Addition of MEA was observed to aid in growth of the algae even up to concentrations of 300ppm for certain operations and strains. An initial decline in the growth was noted and is attributed to the algae adjusting to its new environment. The CO2 fixation is enhanced at a certain concentration of MEA and it was found out that this concentration for freshwater algae operated under simultaneous and sequential operation is 100 and 300 ppm, respectively. For the marine algae operated under simultaneous operation, the MEA concentration is 200ppm. Biodiesel productivity for the Chlorella strains showed a decrease with an increase in MEA concentration while the opposite was observed for the Thalassiosira sp. FAME analysis showed that Chlorella sp. and Thalassiosira sp. strain had the same profile as those presented in literature and had a relatively good amount of oleic acid which is known to improve the quality of biodiesel