The Study of Microalgae Growth Monoraphidium sp. Using Carbon Dioxide Absorption from Biogas via Photo-Bioreactor System

Abstract

The potential of algal in order to capture and reduce the amount of carbon dioxide (CO2) is referred to Carbon dioxide capture or Biological CO2 mitigation. It is the alternative process to take advantage of biochemical reactions of microalgae called photosynthesis. Consequently, microalgae are the single cell that contains with photosynthetic pigment to absorb and utilize energy from sunlight. Particularly, using CO2 is carbon source while photosynthesis to create biomass of cell. This research implements the theory of photosynthetic process to aim upgrading biogas via carbon dioxide absorption. The ability of CO2 absorption impacts the ratio of methane in biogas to become biomethane. The main point of this research focuses on Monoraphidium sp. strain that is cultured in the various growth conditions to affect biomass production, increase of photosynthetic pigment and efficiency in biogas upgrading. The experimental design is divided into three sets of experiments including a control set, aeration and biogas set. Microalgae was cultured in media; BG-11, pH 7, at room temperature with a light intensity of 60 μmol.m−2.s−1 (μmol photons m−2 s −1). The light exposure is 12 hours and dark period 12 hours. Practically, the control and biogas feeding set was operated with a biogas flow rate at 3 ml/min during time 12 hours simultaneously light explosion and aeration. The experiment found that biogas feeding set showed the highest efficiency in the biogas upgrading. The increased biogas reached to 96.41% and the CO2 reduced by 96.78%. In portion of biomass, the weight of dry cell was maximum at 1.42 g/l. In the same way, the amounts of photosynthetic pigment, chlorophyll A, chlorophyll B, chlorophyll AB and carotenoid were detected in the highest level at 15.85, 4.84, 21.22 and 81.48 μg/l, respectively. Presently, the continuous increase of CO2 is the crucial cause of greenhouse gases that are inevitable to become the environmental problem of the global. Accordingly, this research is the alternative approach to solving and reducing the released CO2 through environment.