Progress 10/01/09 to 09/30/14
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
We have found a promising strain of Scenedesmus, which has a high growth rate at a pH less than 7. Chlorella vulgaris and Scenedesmus have been tested with varying amounts of sulfuric acid. Small amounts (6 ppm) appear to have little effect on the culture growth. Intermediate amounts (60 ppm) inhibit growth, but the algae appear to have the ability to recover. Higher amounts (90 ppm) will kill the culture. We did extensive media studies and have developed a urea-based media recipe that support impressive growth for less than traditional algae media, where the nitrogen source is KNO3 We completed a temperature study to determine the relationship between the culture temperature and the expected growth rate of the algae. In addition, a model was developed to determine the expected temperature of the photobioreactor tubes in the greenhouse based on the outside temperature and solar radiation, so that energy management strategies could be used to optimize the growth of the algae. We have also completed studies focusing on flue gas contaminates that could affect the overall algae growth. Specifically, we looked at the effect of various coal fire ashes and elevated sulfuric acid levels. Interestingly, a small amount of ash can actually increase the growth of the algae by supplying additional carbon. We showed the influence of sulfuric acid on the growth of algae and the effect of adding buffer (NaHCO3) showing at what levels the system needs to be buffered in order to maintain optimum pH with the addition of the highly acidic flue gas. Our experiments are done in a lab setting, with lab grade supplies that tend to be more ideal than the supplies that will be accessible for the large-scale installation. Before moving to the large-scale, we looked at some of the aspects of the scaling up, which could affect productivity and economic viability. Specifically, we investigated the effects of using 1) bulk water supplies, 2) commercial grade fertilizers, and 3) sterilization for large liquid systems. Dewatering strategies include flocculation, sedimentation, filtering and drying. The goal is to better understand the dewatering potentials so that we can select the most appropriate dewatering method depending on what the final moisture content is required. This will be important when deciding what value-added products will be made from the algae. We investigated the use of the potential of using anaerobic digestions to breakdown the harvested algae, to recover a fuel product, and to be able to recycle some of the water and nutrients back to the system. The anaerobic digestor (4L) operated well on algae, but there was some evidence that the cell wall was inhibiting the process. We have done experiments with thermal and chemical treatment to try to improve the digestibility of the algae and it appears that we have been able to make some improvements. We have also done some work to try to genetically modify Chlamydomonas reinhardtii , in order to make it more tolerant of high temperatures and low pH values (associated with flue gas). The results of this study are promising, although none of the transformed strains have been successfully cultured in liquid media. Considering the environmental and economic volatility of the project, we have completed a life cycle analysis (LCA) of the entire process in order to better understand the potential tradeoffs and pitfalls. However, the LCA continues to evolve as the overall process is changed and updated. In an effort to continue algae cultivation during the winter months, four snow algae strains (code name SNO 11, 12A, 134, and 54) that strived in the cold temperature were identified and studied. They were cultured in the bold basal medium (BBM) with 3% CO2 and fluorescent lighting (16:8 h light:dark cycle) at 4°C in an environmental chamber. A growth study was first conducted to select one strain with the best growth rate. Based on the result, Chloromonas rosae var. psychrophila (SNO 11) grew better than the others and was chosen for a temperature and pH study. Algae was subjected to cultivation under various temperature and pH levels. Results showed Chloromonas were able to adapt to a wide range of temperature as low as 4°C and up to 22°C and strived at the ultimate pH level of 7.0. Currently, the algae’s lipid, protein, and carbohydrate profiles are being done.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
E, X. 2013. Nutrient Recycling Strategy for Microalgae-Based CO2 Mitigation System. Ph.D. Dissertation, University of Kentucky.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2012
Citation:
Short, K. 2012. Evaluation of Heat Shock Proteins in the Stress Responses of Chlamydomonas reinhardtii, M.S. Thesis, University of Kentucky.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2011
Citation:
Cassidy, K. 2011. Evaluating Algal Growth at Different Temperatures, M.S. Thesis, University of Kentucky.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
E, X., and C. Crofcheck. 2014. Pretreatment of Scenedemus biomass as a potential anaerobic substrate. 2014. Biological Engineering Transactions, 7(1): 41-52.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Shin, H.-Y., J.-H. Ryu, S.-Y. Bae, C. Crofcheck, and M. Crocker. 2014. Lipid extraction from Scenedesmus sp. microalgae for biodiesel production using hot compressed hexane. Fuel, 130:66-69.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Crocker, M., M. H. Wilson, J. Groppo, A. Placido, S. Graham, E. Santillan-Jimenez, T. Morgan, J. Shoup, D. Kim, L. Mills, H. Y. Shin, and C. Crofcheck. 2014. CO2 Recycling using Microalgae for the Production of Fuels. Applied Petrochemical Research, 246.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Crofcheck, C., A. Shea, M. Montross, M. Crocker, and R. Andrews. 2013. Influence of flue gas components on the growth rate of Chlorella vulgaris and Scenedesmus acutus utilized for CO2 mitigation. Transactions of the ASABE, 56(6):1421-1429.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Crofcheck, C., X. E, A. Shea, M. Montross, M. Crocker, and R. Andrews. 2012. Influence of media composition on the growth rate of Chlorella vulgaris and Scenedesmus acutus utilized for CO2 mitigation. Journal of Biochemical Technology, 4(2):589-594.
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Progress 01/01/13 to 09/30/13
Outputs
Target Audience:
Nothing Reported
Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? In the next year, we will continue work on the genetic modification of algae in order to improve its growth rate in the presence of high temperatures and low pH values. We will continue to strive to find new strains that will improve the economics of the algae-based CO2 mitigation system, specifically an algae that grows in colder temperatures.
Impacts
What was accomplished under these goals?
The demonstration unit at East Bend was operational for several weeks. We now have additional information about the effect of using commercial fertilizers as a nutrient source. We have a better understanding of the operation of an algae anaerobic digestor, such that the use of an anaerobic digestor is beneficial to the life-cycle analysis and the economic bottom line.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Crofcheck, C. X. E, A. Shea, M. Montross, M. Crocker, R. Andrews. 2012. Influence of media composition on the growth rate of Chlorella vulgaris and Scenedesmus acutus utilized for CO2 mitigation. Journal of Biochemical Technology, 4(2): 589-594.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2013
Citation:
Crofcheck, C., A. Shea, M. Montross, M. Crocker, R. Andrews. 2013. Influence of flue gas components on the growth rate of Chlorella vulgaris and Scenedesmus acutus utilized for CO2 mitigation. Transactions of the ASABE, In press.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
E, X. 2013. Nutrient Recycling Strategy for Microalgae-Based CO2 Mitigation System. Ph.D. Dissertation, University of Kentucky.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Crofcheck, C., Graham, T., Montross, M. 2013. Algae-Based CO2 Mitigation for Coal-Fired Power Plants. University of Kentucky Cooperative Extension Service AEN-116.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: We have been running experiments with various bulk sources of water, available at the coal-fired power plant or at other sites. We have also done experiments to compare the growth rates of algae with media made from lab grade reagents and commercially available ingredients that will need to be used in the large scale installation. We have also been working with various dewatering strategies, including flocculation, sedimentation, filtering and drying. The goal is to better understand the dewatering potentials so that we can select the most appropriate dewatering method depending on what the final moisture content is required. This will be important when deciding what value-added products will be made from the algae. We have been running experiments to determine the potential of using anaerobic digestions to break down the harvested algae and recover a fuel product and be able to recycle some of the water and nutrients back to the system. The anaerobic digestor (4L) is operating well on algae, but there was some evidence that the cell wall was inhibiting the process. We have done experiments with thermal and chemical treatment to try to improve the digestibility of the algae and it appears that we have been able to make some improvements. We have also done some work to try to genetically modify Chlamydomonas reinhardtii , in order to make it more tolerant of high temperatures and low pH values (associated with flue gas). The results of this study are promising and additional efforts will be focused on this work in the next year. Considering the environmental and economic volatility of the project, we are currently working on a life cycle analysis and a techno-economic analysis of the entire process in order to better understand the potential tradeoffs and pitfalls. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We have started working on the large scale problem associated with using algae to mitigate CO2. We have better information about what water and nutrients need to be used on a large scale. We also have more information about the best way to dewater the algae.
Publications
- Short, K. 2012. Evaluation of Heat Shock Proteins in the Stress Responses of Chlamydomonas reinhardtii, M.S. Thesis, University of Kentucky.
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: We have completed a temperature study to determine the relationship between the culture temperature and the expected growth rate of the algae. In addition, a model was developed to determine the expected temperature of the photobioreactor tubes in the greenhouse based on the outside temperature and solar radiation, so that energy management strategies could be used to optimize the growth of the algae. We have also completed studies looking at the effect of various coal fire ashes on the growth of algae. Interestingly, a small amount of ash can actually increase the growth of the algae by supplying additional carbon. In addition to the studies done last year to show the influence of sulfuric acid on the growth of algae, this year we have added a buffer (NaHCO3) showing at what levels the system needs to be buffered in order to maintain optimum pH with the addition of the highly acidic flue gas. We have also continued our media studies and taken a closer look at the need for micronutrients, vitamins, and EDTA. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Today we have a better media formula then we started with. We have been able to increase the growth rate by adding micronutrients and save on media cost by not adding ingredients that are not necessary (vitamin B and EDTA). We also have a model that will allow for us to make decisions about what kinds of heating and heat recovery will need to be done to operate the algae greenhouse in such a manner that the temperature of the PBR tubes doesn't adversely affect the growth.
Publications
- Cassidy, K. 2011. Evaluating Algal Growth at Different Temperatures, M.S. Thesis, University of Kentucky.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: We currently have several potential set-ups for running algae studies. In our environmental chambers we have the ability to run with constant temperature and consistent lighting (16 h days, 8 h nights). This set-up is used for media development, strain selection, and inoculum preparation with cultures up to 400 mL and capacity of 123 flasks. We also have a varying temperature chamber, where the temperature of the cultures is varied using a circulating water bath through the metal base of the chamber. This system has consistent lighting (16 h days, 8 h nights) and uses cultures up to 400 mL with a capacity of up to 27 flasks. We also have a ventilated and constantly stirred system for use with lower flow rates, which also requires stirring. This set-up is also used with simulated flue gas experiments that need to be properly ventilated. This system utilizes cultures up to 400 mL with a capacity of up to 27 flasks. We also have a pilot-scale, continuously harvested system, which is currently under renovation. This system will be able to run a 60 L culture. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
We have found a promising strain of Scenedesmus, which has a high growth rate at a pH less than 7. Chlorella vulgaris and Scenedesmus have been tested with varying amounts of sulfuric acid. Small amounts (6 ppm) appear to have little effect on the culture growth. Intermediate amounts (60 ppm) inhibit growth, but the algae appear to have the ability to recover. Higher amounts (90 ppm) will kill the culture. The influence of strain selection and media components are also currently under way.
Publications
- No publications reported this period
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Progress 10/01/09 to 12/31/09
Outputs
OUTPUTS: In the last three months, we have set up several experimental set-ups and started running preliminary experiments. We have the capabilities to run experiments in 300 ml flasks or 14 L photobioreactors. We are currently testing two diffrent algae strains, Chlorella vulgaris and Chlorella sorokiniana. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
In the last three months, we have been setting up the experiments and running preliminary tests. Based on these tests, we have determined what media formula to use for subsequent experiment, which uses urea as the nitrogen source and commercially available fertilizer as the micronutrients source.
Publications
- No publications reported this period
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