Socrates Fellows Our Projects Biology Releasing Stored Solar Energy in Pond Scum
Students explore the principles behind biofuels.
Under the central theme of "sustainable energy", students will chemically create biodiesel, a renewable transportation fuel, from algal lipids. Following extraction and purification, students will measure the energy density of their algal biodiesel and compare it to that of petroleum.
ABSTRACT
Microalgae have emerged as an attractive feedstock for the mass production of renewable transportation fuels due to their fast growth rate, flexible habitat preferences, and substantial oil yields. To develop a laboratory as an educational tool that mimics emerging algal biofuel technology, we describe the extraction of algal lipids and explore their transesterification into biodiesel. Students are first introduced to algae as an energy feedstock and taught how to cultivate and harvest algal biomass. Next, students learn how to convert algal biomass to a transportation fuel using transesterification and extraction, including an experimental comparison of base and acid catalyzed transesterification methods. The energy content of homemade algae biodiesel is determined and compared to soybean biodiesel and petroleum diesel using a homemade calorimeter.
GRADE LEVEL: 9-12
DURATION: Algae Biomass Production: 6 weeks of 10 minutes/day
Algae Biomass Harvesting: 1 x 50-minute period
Fuel Synthesis: 1 x 50-minute period for each fuel
Fuel Characterization: 1 x 50-minute period
LEARNING OBJECTIVES:
Students will be able to:
1. Grow and harvest algae biomass
2. Synthesize biodiesel from algal lipids and soybean oil
3. Purify desired organic products (biodiesel) from a complex mixture
4. Determine yields of reaction products (biodiesel)
5. Characterize energy density of homemade fuels using calorimetry
6. Utilize their homemade fuel in a diesel engine
Students will understand:
1. The first law of thermodynamics: that energy cannot be created nor destroyed and that we are harnessing energy, not creating it.
2. That algae store solar energy in the chemical bonds of high energy molecules such as lipids and carbohydrates during photosynthesis.
3. The mechanics of the transesterification reaction that is used to synthesize biodiesel.
4. The concept of polarity and how we can use it as chemists to separate our desired organic product (biodiesel) from a complex mixture.
5. That we are harnessing the stored solar energy within algae by chemically extracting lipids and converting them to a usable transportation fuel (biodiesel).
6. That we can visualize the entire energy flow by combusting the fuels in a calorimeter or diesel engine to demonstrate the conversion of chemical energy to mechanical energy.
Chlamydomonas, a single-celled green algae.
