The Bioeconomy Institute (BEI) is involved in a number of research projects involving algae, which are a promising biomass used in the production of biofuels. Some of our expertise in algae research is leveraged into related areas such as space exploration. BEI has contributed to the construction of an algal production facility located at Iowa State University’s BioCentury Research Farm (BCRF) to produce large amounts of algal biomass for research. See the article in the Center for Crops Utilization Research newsletter.
Biofilm Based Algae Growth Systems
In nature, algae grows suspended in both fresh and salt water. Traditionally farmed algae are also grown suspended in specialized ponds. This growth method has one major disadvantage. For algae to be harvested, they must be separated from a solution that is 99.9 percent water. To separate algae from water is a very cost-intensive process. To reduce this step of dewatering, we have developed systems that allow algae to attach to a surface of a material. This material alternates between a carbon dioxide rich gas phase into a nutritious growth medium phase. This method has been found to increase the growth rate of algae as well as concentrate algal cells on the surface of a material that are later easily scraped off.
The microalga Chlamydomonas reindhardtii is a widely reported species for its capability of using acetic acid for heterotrophic growth, i.e., performing aspiration metabolism in the dark with consumption of organic carbons. Under this condition, algal biomass density is usually higher than in photoautotrophic condition, as it is not limited by the availability of light and CO2. However, the cost incurred from feeding organic carbon sources to the culture is an issue to be addressed from an economic standpoint.
Pyrolytic oil is rich in acetic acid, which is an undesired species due to its corrosivity and low energy content. The aim of this project is to use acetic acid derived from fractionated pyrolytic oil to grow C. reindhardtii for lipid-based fuel production. The fractionated pyrolytic oil contains other compounds, apart from acetic acid, which can inhibit microorganism’s growth. To overcome the toxicity problem, the strategy of directed evolution is applied. The final goal of this work is to replace all the pure acetic acid in the C. reindhardtii culture medium with acetate containing fractionated bio-oil, and to achieve high biomass density and high lipid content.
Using Algae to Produce Oxygen in Space
We are doing research funded by a grant from NASA to build a Controlled Ecological Life Support System (CELSS). This system investigates the possibility of using algae to produce oxygen for astronauts in long term space missions, such as life on the international space station. Research has shown that algae are an ideal candidate for oxygen generation in space due to its rapid photosynthetic rate. To do research on algal growth in outer space we built a photobioreactor that mimics space conditions. Using this unique photobioreactor we are currently focused on optimizing algae growth parameters in order to identify the optimal conditions for oxygen generation in space.
Improving Air Quality in Concentrated Animal Farming Operation using Microalgae
Our lab is doing a project to mitigate ammonia gas (NH3) using microalgae. Ammonia gas volatilization from accumulated animal manure is a big concern in animal house operations. A high amount of ammonia emissions can cause worker health concerns as well as environmental problems, so decreasing the ammonia gas is needed. Feeding ammonia gas to microalgae is environmentally and economically desirable because feeding waste ammonia gas to microalgae can reduce both ammonia gas emissions and algae cultivation cost. The grown algae can be used as a high quality animal feed as well.
Our experiment is to find the optimal growth condition of microalgae and to know the nitrogen fate in the whole process by calculating the nitrogen mass balance. The microalgae strain used is Scenedesmus dimorphus and the growth conditions are combinations of different ammonia gas concentrations, pH, and dilution rates. The results so far indicate the microalgae can reduce the ammonia gas up to 96 percent of ammonia gas.
For More Information
Food Science and Human Nutrition
2312 Food Science
Iowa State University
Ames, IA 50011
Note: The Algae lab is located in 1125 Biorenewables Research Laboratory, Iowa State University.