Carbon dioxide biofixation by Chlorella vulgaris at different CO 2 concentrations and light intensities (original) (raw)
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Microalgae have the potential to recycle and bioremediate CO 2 and also produce chemical energy in the form of biomass. The potential production of renewable energy and high value products (i.e. carotenoid, antioxidants and polyunsaturated fatty acids) makes large scale microalgal cultivation an attractive application. To achieve high productivity all microalgae cultures require CO 2 addition. Various microalgae species have shown different capabilities to bioremediate CO 2 . This review article reports biomass concentrations, biomass productivities, and CO 2 fixation rates of several microalgae and cyanobacteria species under different input CO 2 concentrations. The effects of important factors such as type of photobioreactor, temperature, and light intensity on CO 2 removal are also discussed.
Reduction of CO2 by a high-density culture of Chlorella sp. in a semicontinuous photobioreactor
Bioresource Technology, 2008
The microalga incorporated photobioreactor is a highly efficient biological system for converting CO 2 into biomass. Using microalgal photobioreactor as CO 2 mitigation system is a practical approach for elimination of waste gas from the CO 2 emission. In this study, the marine microalga Chlorella sp. was cultured in a photobioreactor to assess biomass, lipid productivity and CO 2 reduction. We also determined the effects of cell density and CO 2 concentration on the growth of Chlorella sp. During an 8-day interval cultures in the semicontinuous cultivation, the specific growth rate and biomass of Chlorella sp. cultures in the conditions aerated 2-15% CO 2 were 0.58-0.66 d À1 and 0.76-0.87 g L À1 , respectively. At CO 2 concentrations of 2%, 5%, 10% and 15%, the rate of CO 2 reduction was 0.261, 0.316, 0.466 and 0.573 g h À1 , and efficiency of CO 2 removal was 58%, 27%, 20% and 16%, respectively. The efficiency of CO 2 removal was similar in the single photobioreactor and in the six-parallel photobioreactor. However, CO 2 reduction, production of biomass, and production of lipid were six times greater in the six-parallel photobioreactor than those in the single photobioreactor. In conclusion, inhibition of microalgal growth cultured in the system with high CO 2 (10-15%) aeration could be overcome via a high-density culture of microalgal inoculum that was adapted to 2% CO 2. Moreover, biological reduction of CO 2 in the established system could be parallely increased using the photobioreactor consisting of multiple units.
Estimation of carbon dioxide sequestration potential of microalgae grown in a batch photobioreactor
Bioresource Technology, 2015
The carbon dioxide (CO 2) sequestration potential of two microalgae, Chlorella pyrenoidosa and Scenedesmus abundans was evaluated in a tubular batch photobioreactor with provision for continuous flow of 10% CO 2 enriched air through the headspace. CO 2 sequestration and biomass growth was affected by gas flow rate over the range 20 to 60 ml/min and 40 ml/min was found to maximize algal growth and CO 2 sequestration. Moles of CO 2 sequestered over 20 hours at a gas flow rate of 40 ml/min was estimated using a novel rapid screening approach as 0.096 and 0.036, respectively, for C. pyrenoidosa and S. abundans. At this gas flow rate the maximum growth rate was 4.9 mgL-1 h-1 and 2.5 mgL-1 h-1 for C. pyrenoidosa and S. abundans, respectively. The CO 2 sequestration and growth rate were comparable at height/diameter ratio of 8 and 16.
Gravity : Jurnal Ilmiah Penelitian dan Pembelajaran Fisika
A closed photobioreactor design has been fabricated, aimed to determine the basic concept for microalgae Chlorella vulgaris development. This study employed a flat-plate type with dimensions of 16x20x25 cm with the effectiveness of 3000 ml culture media and two 20 watt 220 volt tungsten halogen lamps, which were placed on the right and left sides of the reactor with a light intensity of 1000 lux. This study employed two photobioreactors, type-I without CO 2 supply and type-II with CO 2 supply as much as 25%. The initial cell density of Chlorella vulgaris culture was 14,694 x10 5 cells/ml; then observations were made every day using a Haemocytometer. O 2 concentration data were collected every day 3 times with irradiation time of 1, 6, and 9 hours using the O 2 gas sensor (KE-50 type). The determination of the O 2 concentration value in the photobioreactor on the 3 rd day was 0.69%.
Effect of CO 2 aeration on cultivation of microalgae in luminescent photobioreactors
Biomass & Bioenergy, 2016
This photobioreactor study investigated the influence of CO 2 aeration on biomass production, carbon dioxide fixation rate, pH, cell's essential elements such as carbon, nitrogen, and hydrogen, as well as lipid content, whilst under a range of luminescence-modified lighting conditions. The effect of aeration with pure air (comprising 0.03% CO 2) on the CO 2 fixation rate was insignificant compared to the higher concentrations used. Results showed that, with the exception of blue PBR, increasing CO 2 concentrations in the air stream enhanced the fixation rate of CO 2 in C. vulgaris. Cyanobacteria cells showed significant tolerance to 15% CO 2. The results obtained demonstrated that the combination of blue light and 15% CO 2 provided a condition in which higher rates of lipid accumulation was induced in both algal strains. The highest lipid content observed at this condition was 36.6% obtained in G. membrancea. Aeration with 15% CO 2 enhanced lipid production of G. membranacea, to at least twice the amount produced at 5% CO 2 in all photobioreactors. The most significant difference between the 5% and 15% CO 2 aeration conditions was observed in the yellow PBR, in which the lipid content was enhanced up to six times.
Science of The Total Environment, 2019
The increase in atmospheric CO 2 concentration and the release of nutrients from wastewater treatment plants (WWTPs) are environmental issues linked to several impacts on ecosystems. Numerous technologies have been employed to resolves these issues, nonetheless, the cost and sustainability are still a concern. Recently, the use of microalgae appears as a cost-effective and sustainable solution because they can effectively uptake CO 2 and nutrients resulting in biomass production that can be processed into valuable products. In this study single (Spirulina platensis (SP.PL) and mixed indigenous microalgae (MIMA) strains were employed, over a 20-month period, for simultaneous removal of CO 2 from flue gases and nutrient from wastewater under ambient conditions of solar irradiation and temperature. The study was performed at a pilot scale photo-bioreactor and the effect of feed CO 2 gas concentration in the range (2.5-20%) on microalgae growth and biomass production, carbon dioxide bio-fixation rate, and the removal of nutrients and organic matters from wastewater was assessed. The MIMA culture performed significantly better than the monoculture, especially with respect to growth and CO 2 bio-fixation, during the mild season; against this, the performance was comparable during the hot season. Optimum performance was observed at 10% CO 2 feed gas concentration, though MIMA was more temperature and CO 2 concentration sensitive. MIMA also provided greater removal of COD and nutrients (~83% and >99%) than SP.PL under all conditions studied. The high biomass productivities and carbon bio-fixation rates (0.796-0.950 g dw .L −1 .d −1 and 0.542-1.075 g C .L −1 .d −1 contribute to the economic sustainability of microalgae as CO 2 removal process. Consideration of operational energy revealed that there is a significant energy benefit from cooling to sustain the highest productivities on the basis of operating energy alone, particularly if the indigenous culture is used.
Energies
Direct study of CO2 capture efficiency during microalgae Arthrospira platensis cultivation at high CO2 concentrations was carried out. Microalgae were grown in a 90 L photobioreactor on Zarrouk’s medium prepared with distilled water. Three 15-day experiments were carried out with different initial CO2 concentrations: 1, 5, and 9 vol.%. During the experiments, both the change in the optical density of the microalgae suspension and the direct change in the CO2 concentration in the chamber were measured. The maximum decrease in CO2 concentration due to the growth of microalgae was 0.10 vol.% (CO2)/day in the experiment with an initial CO2 concentration of 5 vol.%. Growth rate of biomass density was 79.4, 76.3, and 48.4 (mg/L)/day at 1, 5, and 9 vol.% CO2 concentrations, respectively. During the experiment with initial CO2 concentrations of 1 and 5 vol.%., pH of the culture medium was increased, but pH was decreased from 9.2 to 8.8 at 9 vol.%. In general, good viability (high quality of...
Algae - Organisms for Imminent Biotechnology, 2016
The global warming issue caused mainly by carbon dioxide (CO 2) has triggered various efforts to reduce excess amount of CO 2 emitted into the atmosphere. A viable option is to utilize biomass production potential of microalgal consortium in aquatic ecosystem that constantly requires CO 2 to perform photosynthesis. This study aims to provide scientific contributions to the development of environmental studies, particularly of using microalgal consortiums as carbon capture and storage (CCS) agent by engineering their culture conditions. A number of studies analyzing biological reduction of atmospheric CO 2 by using CO 2 absorption capability of terrestrial plants have been facing many difficulties. Compared to various terrestrial plants, microalgae are generally considered photosynthetically more efficient. Exploitation of microalgal capability has numerous advantages, including their faster regeneration time, ability to grow in less space than terrestrial plants, and because the cultivation of microalgae can be done on a small-scale or large-scale operation, under controlled conditions, and is independent to climatic changes. Taking into account long-term advantages, this study is a preliminary study which is expected to be able to provide information and feedback regarding integrated microalgal culture system that may lead to alternative solutions of ecofriendly and sustainable environmental management technology that are capable of mitigating environmental problems caused by CO 2 (as greenhouse gas) emissions. Hence, the results of this research could be implemented by building urban microalgal ponds in efforts to develop sustainable cities in terms of CO 2 emission reduction in urban areas.