Biofixation of Carbon dioxide by Chlamydomonas sp. in a Tubular Photobioreactor

Biofixation of carbon dioxide by Spirulina sp. and Scenedesmus obliquus cultivated in a three-stage serial tubular photobioreactor

This work describes the effect of mixed culture on reduction of carbon dioxide into methane during biogas production. Various mixed cultures, such as IMS, IWT, IRP, and IMW1, were isolated from marshy soil, decaying woody tissue, rice paddy soil, and mixture of activated sludge from municipal waste treatment plant along with a cow dung-based biogas plant (IMW1), respectively, and separately grown in cow dung slurry. Combinations of these mixed inocula were used for biogas production at 35°C in a 1.5 L batch reactor. A relatively high average yield of methane (0.345 Lg−1 volatile solid), low average yield of carbon dioxide (0.131 gL−1VS), and maximum 72% methane and 23% carbon dioxide content in biogas during 25–30 days was obtained with inoculum IRP. Whereas a corresponding average yield of methane (0.313, 0.315, 0.308 Lg−1VS), carbon dioxide (0.164, 0.158, and 0.167 Lg−1VS), and average methane content (70, 68, and 68% during 25–30 d) were observed with inocula IMS, IWT, and IMW1, respectively. Experimental results found that a 21.5% reduction in the average yield of carbon dioxide along with a 12% increase in average yield of methane and 4% increase in methane content (25–30 d) in biogas was observed with IRP, whereas a 1.8 and 5.4% reduction of carbon dioxide was found with a small increase in average methane yield 2 and 2.3% and in methane content 2% and no change (25–30 d) was observed with IMS and IWT mixed cultures as compared to IMW1 inoculum. These results of the experiments indicate that mixed microbial culture (IRP) can be used for improved quality biogas (72% methane and 23% carbon dioxide) production.

Carbon dioxide makes up 72% of all greenhouse gases produced, which makes it the leading source of air pollution. Certain green algal species such as Chlorella vulgaris fix the carbon dioxide into fatty acids present in cells in a process known as “carbon dioxide biofixation”. This project tests the effect of different algal growth media on the efficiency of Chlorella vulgaris’s carbon dioxide biofixation. In the testing process, we added Chlorella vulgaris to four bottles, each containing four different substances (distilled water, Blue Green 11 medium, Bold’s Basal Medium, and Guillard’s f/2 medium), and cultured for eight days. Each algae and medium mixture was then divided equally into three smaller bottles and rotated for three days. To compare data, we measured the change in carbon dioxide content by subtracting the carbon dioxide content of the bottles with algae to a similar bottle without algae. The results for the average change in carbon dioxide content were 59.3 ppm for Blue Green 11 medium and algae, 50.6 ppm for Guillard’s medium and algae, 22.6 ppm for Bold’s Basal Medium and algae, and 10 ppm for distilled water and algae. The Blue Green 11 medium most effectively decreased carbon dioxide content of the bottles. This supported our hypothesis that algae's capacity for biofixation can be greatly enhanced through the effective use of media, a finding that has extensive real-world benefits in reducing pollution.

Characteristics of the large-scale circulation during episodes with high and low concentrations of carbon dioxide and air pollutants at an arctic monitoring site in winter

Microalgae are among the most productive biological systems for converting sunlight into chemical energy, which is used to capture and transform inorganic carbon into biomass. The efficiency of carbon dioxide capture depends on the cultivation system configuration (photobioreactors or open systems) and can vary according to the state of the algal physiology, the chemical composition of the nutrient medium, and environmental factors such as irradiance, temperature and pH. This mini-review is focused on some of the most important environmental factors determining photosynthetic activity, carbon dioxide biofixation, cell growth rate and biomass productivity by microalgae. These include carbon dioxide and O2 concentrations, light intensity, cultivation temperature and nutrients. Finally, a review of the operation of microalgal cultivation systems outdoors is presented as an example of the impact of environmental conditions on biomass productivity and carbon dioxide fixation.

Diffusivity is a strong function of concentration and an important transport property. Diffusion of multiple species is far more frequent than the diffusion of one species. However, there are limited experimental data available on multi-component diffusivity. The objective of this study is to develop an optimal control framework to determine multi-component concentration-dependent diffusivities of two gases in a non-volatile phase such as polymer. In Part 1 of this study, we derived a detailed mass-transfer model of the experimental diffusion process for the non-volatile phase to provide the temporal masses of gases in the polymer. The determination of diffusivities is an inverse problem involving principles of optimal control. Necessary conditions are determined to solve this problem. In Part 2 of this study, we utilized the results of Part 1 to determine the concentration-dependent, multi-component diffusivities of nitrogen and carbon dioxide in polystyrene. To that end, solubility and diffusion experiments are conducted to obtain necessary data. In the ternary system of nitrogen (1), carbon dioxide (2), and polystyrene (3), the diffusivities and D11, D12, D21, and D22 versus the gas mass fractions are two-dimensional surfaces. The diffusivity of carbon dioxide was found to be greater than that of nitrogen. The value of the main diffusion coefficient D11 was found to increase as the concentration of carbon dioxide increased. The highest value of D11 obtained was 2.2 X 10^-8m^2s^-1 for nitrogen mass fraction of 3.14 X10^-4 and for a carbon dioxide mass fraction of 5.67 X 10^-4 . The cross-diffusion coefficient increased as the concentrations of nitrogen and carbon dioxide increased. The diffusivity reached its maximum value when the concentrations of nitrogen and carbon dioxide were at their maximum values. The diffusivity was of the order of 10^-9m^2s^-1. The diffusivity of the cross-diffusion coefficient D21 was found to be increased for the mass The diffusivity of the cross-diffusion coefficient was found to be increased for the mass fractions of carbon dioxide ranging from 0 to 1.70 X 10^-3 . The diffusivity was found to be of the order of . The diffusion coefficient, D22, was found to increase with the concentrations of nitrogen and carbon dioxide, D22 remained high with low concentrations of carbon dioxide. The diffusivity was found to be of the order of 10^-7m^2s^-1

Diffusivity is a strong function of concentration and an important transport property. Diffusion of multiple species is far more frequent than the diffusion of one species. However, there are limited experimental data available on multi-component diffusivity. The objective of this study is to develop an optimal control framework to determine multi-component concentration-dependent diffusivities of two gases in a non-volatile phase such as polymer. In Part 1 of this study, we derived a detailed mass-transfer model of the experimental diffusion process for the non-volatile phase to provide the temporal masses of gases in the polymer. The determination of diffusivities is an inverse problem involving principles of optimal control. Necessary conditions are determined to solve this problem. In Part 2 of this study, we utilized the results of Part 1 to determine the concentration-dependent, multi-component diffusivities of nitrogen and carbon dioxide in polystyrene. To that end, solubility and diffusion experiments are conducted to obtain necessary data. In the ternary system of nitrogen (1), carbon dioxide (2), and polystyrene (3), the diffusivities and D11, D12, D21, and D22 versus the gas mass fractions are two-dimensional surfaces. The diffusivity of carbon dioxide was found to be greater than that of nitrogen. The value of the main diffusion coefficient D11 was found to increase as the concentration of carbon dioxide increased. The highest value of D11 obtained was 2.2 X 10^-8m^2s^-1 for nitrogen mass fraction of 3.14 X10^-4 and for a carbon dioxide mass fraction of 5.67 X 10^-4 . The cross-diffusion coefficient increased as the concentrations of nitrogen and carbon dioxide increased. The diffusivity reached its maximum value when the concentrations of nitrogen and carbon dioxide were at their maximum values. The diffusivity was of the order of 10^-9m^2s^-1. The diffusivity of the cross-diffusion coefficient D21 was found to be increased for the mass The diffusivity of the cross-diffusion coefficient was found to be increased for the mass fractions of carbon dioxide ranging from 0 to 1.70 X 10^-3 . The diffusivity was found to be of the order of . The diffusion coefficient, D22, was found to increase with the concentrations of nitrogen and carbon dioxide, D22 remained high with low concentrations of carbon dioxide. The diffusivity was found to be of the order of 10^-7m^2s^-1

ASSIMILATION AND RESPIRATION OF EXCISED LEAVES AT HIGH CONCENTRATIONS OF CARBON DIOXIDE

Lactic acid, carbon dioxide and human sweat stimuli were presented singly and in combination to femaleAedes aegypti(Linnaeus) within a wind-tunnel system. The take-off, flight, landing and probing responses of the mosquitoes were recorded using direct observation and video techniques. The analyses determined the nature of the response to different stimuli and the concentration ranges within which specific behaviours occurred. A threshold carbon dioxide concentration for taking-off of approximately 0.03% above ambient was detected. Lactic acid and human sweat samples did not elicit take-off when presented alone, however, when they were combined with elevated carbon dioxide, take-off rate was enhanced in most of the combinations tested. Flight activity was positively correlated with carbon dioxide level and some evidence for synergism with lactic acid was found within a narrow window of blend concentrations. The factors eliciting landing were more subtle. There was a positive correlation between landing rate and carbon dioxide concentration. At the lowest carbon dioxide concentration tested, landing occurred only in the presence of lactic acid. Within a window of low to intermediate concentrations, landing rate was enhanced by this combination. At the highest carbon dioxide concentration, landing was however inhibited by the presence of lactic acid. The sweat extract elicited landings in the absence of elevated carbon dioxide. This indicated the presence of chemical stimuli, other than lactic acid, active in the short range. Probing occurred only at low carbon dioxide concentrations and there was no probing when lactic acid alone was tested. There was however probing in the presence of combined stimuli, the level of response seemed to be positively correlated with the ratio of carbon dioxide and lactic acid concentrations.

The increase in carbon dioxide in the atmosphere is one of the main causes of global warming. Remote sensing technology has become an important means of monitoring the distribution of carbon dioxide gas. By remotely monitoring the temporal and spatial distributions of atmospheric carbon dioxide, people can further deepen their understanding of the global carbon process. The GOSAT (Greenhouse Gases Observing SATellite) CO2 L4B concentration data from 2010 to 2015 were validated using local station atmospheric data. The spatial and temporal distributions of the carbon dioxide concentration and its variation characteristics were analyzed. Based on the total primary productivity data and human emissions of carbon dioxide data, the influencing factors of spatial variations in carbon dioxide were analyzed. The results show that: (1) The correlation coefficient between GOSATL4B data and ground-measured data is above 0.95, which indicates that the remotely acquired data have high precision and stability. (2) The spatial distribution characteristics of carbon dioxide at different atmospheric pressure heights are quite different. The variation in the long-term series mean of carbon dioxide concentration levels at 17 vertical heights was studied. The fluctuations in concentration changes at different height levels vary, and the closer to the surface, the greater the fluctuation is. The near-surface carbon dioxide concentration (975 hPa) has the largest fluctuation. When the atmospheric pressure is low (for example, 150 or 100 hPa), the high carbon dioxide concentration region is banded and concentrated near the equator. The trends in carbon dioxide concentration over land and sea surfaces are similar, and the common pattern is that the concentration of carbon dioxide has been increasing. (3) The near-surface carbon dioxide concentration (975 hPa) has clearly different spatial characteristics. There are four high-value centers across the globe: East Asia, western Europe, the US East Coast, and Central Africa. The concentration of carbon dioxide in the Northern Hemisphere near the ground is higher than that in the Southern Hemisphere. The fluctuation in the Southern Hemisphere is relatively small, and the trend is opposite that in the Northern Hemisphere. (4) The concentration of carbon dioxide showed a significant growth trend during the study period. By studying the change characteristics of the monthly global average at the 975 hPa level (approximately 300 m above sea level) from January 2010 to October 2015, it can be seen that the global CO2 concentration has been above 400 ppm for most of the year, and it is increasing each year. (5) Compared with the Southern Hemisphere, the cyclical changes in carbon dioxide concentration in the Northern Hemisphere are obvious and large, while the trend in the Southern Hemisphere is relatively stable, and the change is small. There are opposite trends in the cyclical changes in the carbon dioxide concentration in the Northern and Southern Hemispheres. When the carbon concentration in the Northern Hemisphere resides over the annual high-value area, the Southern Hemisphere has a low-value area of carbon dioxide concentration every year. In addition, the change in carbon dioxide concentration during the year is obvious with seasonal changes. This should be related to changes in vegetation phenology and different seasons in the Northern and Southern Hemispheres. (6) Four countries in East Asia (Korea, Mongolia, Japan and China) from 2010 to 2014 were selected to analyze the relationship between GPP (gross primary production) and near-surface carbon dioxide concentration. These two factors have a significant inverse correlation. When carbon dioxide is at a minimum, the GPP is at its peak, and when carbon dioxide reaches its peak, the GPP reaches a minimum. The above relationship fully indicates that terrestrial ecosystems play an important role as carbon sink contributors in the carbon cycle. (7) The relationship between atmospheric carbon dioxide and carbon dioxide data from human activities from the Global Atmospheric Research Emissions Database was analyzed. The former is significantly and positively correlated with carbon dioxide emissions caused by human activities, indicating that human activities are an important factor in the increase in carbon dioxide.

This paper discusses the potential for algal biofuel production under resource-limited conditions in Texas. Algal biomass and lipid production quantities are estimated using a fully integrated biological and engineering model that incorporates primary resources required for growth, such as carbon dioxide, sunlight and water. The biomass and lipid production are estimated at the county resolution in Texas, which accounts for geographic variation in primary resources from the Eastern half of the state, which has moderate solar resources and abundant water resources, to the Western half of the state, which has abundant solar resources and moderate water resources. Two resource-limited scenarios are analyzed in this paper: the variation in algal biomass production as a function of carbon dioxide concentration and as a function of water availability. The initial carbon dioxide concentration, ranging from low concentrations in ambient air to higher concentrations found in power plant flue gas streams, affects the growth rate and production of algal biomass. The model compares biomass production using carbon dioxide available from flue gas or refinery activities, which are present only in a limited number of counties, with ambient concentrations found in the atmosphere. Biomass production is also estimated first for counties containing terrestrial sources of water such as wastewater and/or saline aquifers, and compared with those with additional water available from the Gulf of Mexico. The results of these analyses are presented on a series of maps depicting algal biomass and lipid production in gallons per year under each of the resource-limited scenarios. Based on the analysis, between 13.9 and 154.1 thousand tons of algal biomass and 1.0 and 11.1 million gallons of lipids can be produced annually.

In situ methane enrichment in anaerobic digestion of sewage sludge has been investigated by experiments and by modeling. In this first part, the experimental work on the desorption of carbon dioxide and methane from sewage sludge is reported. The bubble column, had a diameter of 0.3 m and a variable height up to 1.8 m. At operation the dispersion height in the column was between 1 and 1.3 m. Outdoor air was used. The column was placed close to a full-scale sewage sludge digester, at a municipal wastewater treatment plant. The digester was operated at mesophilic conditions with a hydraulic retention time of about 20 days. The bubble column was operated to steady-state, at which carbon dioxide concentration and alkalinity were determined on the liquid side, and the concentration of carbon dioxide and methane on the gas side. Thirty-eight experiments were performed at various liquid and gas flow rates. The experimental results show that the desorption rates achieved for carbon dioxide ranges from 0.07 to 0.25 m(3) CO(2)/m(3) sludge per day, which is comparable to the rate of generation by the anaerobic digestion. With increasing liquid flow rate and decreasing gas flow rate the amount of methane desorbed per amount of carbon dioxide desorbed increases. The lowest methane loss achieved is approximately 2% of the estimated methane production in the digestion process.

Comparative analysis of the outdoor culture of Haematococcus pluvialis in tubular and bubble column photobioreactors

Comparative analysis of top-lit bubble column and gas-lift bioreactors for microalgae-sourced biodiesel production

This experiment was conducted to observe the effect of the composition of atmospheric gases on the respiration of fruits and vegetables. The average of repiration rate of eggplants, Japanese pears, spinach and cauliflower (under storage in modified atmosphere) were lower than that under storage in air. Especially, the respiration rate of the products stored in modified atmosphere conta fined 5% oxygen and 5% carbon dioxide was about half of that in air. (Experiment I.)It is clear that a decline in the respiration of these products in storge is brought about by a combination of super-normal carbon dioxide concentration and reduced oxygen concentration. However, the data in experiment I has not been elucidated which is the main fatter concerning the reduction in respiration.In order to test the precise contribution of each of these fatter, experiment II was conducted both tests on oxygen and carbon dioxide concentrations in atmospheric gases on the respiration of vegetables. Carbon dioxide test was carried out at the range of 0-20% and oxygen test was carried out at the range of 5-25%.In this experiment, the respiration rate of some vegetables could be controlled either by decrease of oxygen concentration or by increase of carbon dioxide concentration.It was found that there was three phases to control the respiration rate in practical CA-storage. Three phases were as follows: (1) decrease of oxygen concentration, (2) increase of carbon dioxide concentration and (3) both decrease of oxygen concentration and increase of carbon dioxide concentration. Vegetables showed pattern (1) were spinach, pea in pod, kidney bean, lettuce, bell peppers and eggplants. They were very sensitive to the oxygen content in atmospheric gases. Cauliflower belonged to pattern (2) which shows relatively sensitive carbon dioxide concentration. Other vegetables which are pattern (3) are strawberries, celery, tomatoes, welsh onion and garden asparagus. These vegetables were sensetive to carbon dioxide and oxygen concentration in the atmospheric gases. Thus, it was considered that the response of vegetables to special gases reducing the respiration was different from the kinds of vegetables.