This Small Business Innovation Research Phase I project will develop a method for lysing algae and recovering the oil without pre-concentrating or dewatering. A promising feedstock for biofuels is photosynthetic algae, which can produce lipids in much higher yields per acre then can terrestrial crops. Currently, the harvesting and extracting of the oil consumes 40%-60% of the energy required to produce biodiesel from algae. If the lipids and other compounds can be collected directly from the growth media these expenses would be entirely avoided. Cavitation is a good candidate as it has been shown to rupture algal cell membranes and release cell contents. Feasibility of hydrodynamic jet cavitation as a practical and easily scalable method will be demonstrated. This process will be inline and will use shear flow and local accelerations to create high pressure fluctuations in the liquid causing bubbles to grow and collapse using a fraction of the energy required for ultrasonic cavitation. Hydrodynamic submerged jet cavitation also creates clouds of fine microbubbles that can attach to lipids and lift them to the surface. By controlling the creation and collection of foam, the lipids can be concentrated and recovered from the growth media with minimal energy input.
The broader impact/commercial potential of this project is the development of new fuel resources that would benefit the nation by providing a stable energy source, reducing gas imports and dependence on foreign nations, and reducing greenhouse gas emissions. Commercialization of microalgae for biofuels and nutritional uses is expanding rapidly in the USA and the world. Eliminating the major energy requirements of harvesting and extraction will increase the profitability of biofuel production from algae. Providing a technology capable of achieving this will be very marketable. This technology could also be applied to other biotechnologies in which microorganisms are used to produce high value products, such as pharmaceuticals, nutraceuticals, or biorefining. This process could be used for more economical and more sustainable use of bioresources. In addition, greater understanding of the behavior of microorganisms in hydrodynamic flows would benefit the fields of biotechnology, health care, and water purification.
2M11028-NSF-1B Project: Extraction of Lipids from Algae and Collection by Foam Fractionation Contractor: Dynaflow, Inc. Principal Investigator: Dr. Gregory Loraine Contract Number: IIP-1113384 Contract Period: Jul1, 2011 – June 30, 2012 Period of Report: Jul 1, 2011 – Jun 30, 2012 Algae convert carbon dioxide and sunlight into organic carbon and oxygen. A large portion of this organic carbon, 20% to 60% of the dry weight of the organism, is in the form of oils that can be transformed into biodiesel suitable for combustion in conventional diesel engines. There are several benefits to using algae as a feedstock crop for biodiesel production. First, the yield of oil per acre can be hundreds of times greater than that of oil seeds such as soy, corn, and palm. Second, algae are not a food crop so using it for fuel production won’t deplete the existing human food supply. In addition, algae can be grown on otherwise unproductive land using non-potable water. Thus, biofuel production can be increased without reducing the available food supply. However, utilization of algae for fuel production is currently limited by several technical hurdles, such as scaling mass production systems, developing more productive strains of algae, and the high costs of harvesting the algae and extracting the oil. Currently, the algae must be harvested from the water in which they are grown before the oils can be recovered. Multiple dewatering, and drying steps are required to concentrate the algae. The dried algae cells are then broken open, and the oil is released. These harvesting and extraction processes drive up the cost of algae oil and makes it much more expensive to produce than petroleum diesel. A simpler, cost effective means of recovering the oil from the algae must be found before algae will be a viable source of renewable fuel. In this NSF SBIR project a method for extracting and recovering oil from algae while still in water was demonstrated. This was accomplished by using the Dynaflow proprietary DynaSwirl® cavitating jet to rupture the algae cell walls in the growth media without the need of prior dewatering and centrifugation. The cavitation, high stresses, and shear produced by the cavitating jets open up the cell walls and release the lipids. The oil was then recovered in the same treatment step by taking advantage of the small bubbles produced during cavitation. By using the cavitation processes to both rupture the algae in the growth media and extract the released oil, the DynaSwirl® processes can also conserve water and nutrients by returning to the growth tank the remaining liquid without need for further treatment. With additional support from NSF we will continue to develop the process and will commercialize it. We have been working with algae producers and have been able to make some early sales of small testing units. Based on the R&D results from the NSF SBIR project and further development with industry, the prospects for commercialization of this technology are good.
