Designing Synthetic Trees: a Novel Approach for Producing Energy and Water Efficient Biofuels

March 20, 2013


Ph.D. student Mr. Thomas Murphy (on the left) and Dr. Halil Berberoglu (on the right) in their laboratory with a sample of their algae they use for biofuel production.

Ph.D. student Mr. Thomas Murphy (on the left) and Dr. Halil Berberoglu (on the right) in their laboratory with a sample of their algae they use for biofuel production.

Assistant Professor Halil Berberoglu's First Five Years

Halil Berberoglu, an assistant professor in the Department of Mechanical Engineering at The University of Texas at Austin, joined the department in 2008 working in the area of alternative energy. He has recently been the recipient of several prestigious awards and honors. In 2012 he was one of only 100 invited guests to attend the National Academy of Science’s Frontiers in Engineering Symposium. If invited, most people only attend once in their lives, but he’s been invited back to host a panel discussion in 2013 on moving away from dependence on fossil fuel. Recently, he was also awarded the Norman Hackerman Award from the Texas Education Board. This monetary award goes to a young scientist to fund additional research work. Just a few weeks ago, he found out he had received a CAREER Award (Faculty Early Career Development) from the National Science Foundation (NSF). This is approximately $400,000 in research funding over a five-year period and is only awarded to tenure-track assistant professors.

Berberoglu is working on several different research projects right now, but we will discuss his work to design a novel alternative energy solution using synthetic plants to produce an oil that could serve as a renewable fuel source.

During his first years at The University of Texas at Austin, he worked primarily with algae, searching for fast growing species that could be cultivated as an energy source. Upon realizing the limitations of conventional algae in fuel production, he and Ph.D. student Tom Murphy are taking another approach to biosynthesis, using synthetic algae. They have teamed up with Texas A&M and NASA to research this exciting concept. Their ultimate goal is to produce renewable fuels on earth and provide life support in space for astronauts.

View on YouTube. Video Description:Dr. Berberoglu and Mr. Murphy are working with NASA to design synthetic trees using photosynthetic biofilms, which use much less water and energy than conventional photobioreactors for producing renewable fuels on earth and providing life support in space for astronauts.

Artificial Photosynthesis

This research aims to make biofilm out of artificial leaves that mimic how plants function. This work is collaborative with NASA ’s Ames Research Center. The research has implications for water efficient cultivation of algae. Currently, traditional algae growth requires large volumes of water and energy—this method could show significant savings in both water and energy consumption. His biofilm algae will mimic light and CO2 capture using man-made materials—artificial photosynthesis.

(From the AMES site)

Ames is leading the Agency into a fledgling field of research—synthetic biology—where science and technology are brought together to design and build new biological functions and systems. Biology on Earth readily demonstrates that life is an efficient user of resources around it, turning those resources into habitats, materials and forms that perform critical functions. Synthetic biology in space represents a new challenge—of designing organisms to perform reliable functions that an astronaut may one day depend on. NASA’s synthetic biology program is to provide transformative biological tools and technologies for the benefit of space exploration, science and the economy.

NASA wants to power the International Space Station as a self-contained, renewable energy system in space. Currently, the space station’s power and water supply is not renewable, thus requiring frequent payloads of water and oxygen. Berberoglu and Murthy are working with the AMES team and researchers at Texas A&M to put a synthetic algae experiment in the space station and hope to deploy their test equipment within the next year. NASA’s objective in funding this research is to provide life support for astronauts, lower the overall mass of the space station system, and make the balance of energy, air and water balanced to the usage. The plan is to simulate the life-sustaining systems that exist on earth in space. This would entail using astronaut wastes to feed and fuel the growth of the algae, which would convert carbon dioxide (waste product from breathing) back to oxygen and recycle organic waste back into water and power. Experimentation is essential as the synthetic algae will not grow exactly the way it does on earth.

Dr. Berberoglu and Mr. Murphy grow and evaluate the performance of algal biofilms in special chambers where they can control the environmental inputs. The detail  photo on the right shows a close-up on one of the experimental chambers.

Dr. Berberoglu and Mr. Murphy grow and evaluate the performance of algal biofilms in special chambers where they can control the environmental inputs. The detail photo on the right shows a close-up on one of the experimental chambers.

How the Synthetic Leaves Work:

The synthetically-grown algae is a genetically modified strain that is different from conventional (natural) algae in several ways. It grows faster and it secretes oil when it is stressed. Conventional algae does not secrete oil—that is not a natural function. The oil is a fat, and fat is a storage mechanism used by organisms to survive in hard times. Berberoglu’s and Murthy’s basic premise is to grow healthy algae with a proper supply of nutrients— CO2 and light, and then cut the food source. When the supply of nutrients (mainly nitrogen) is gone, the synthetic algae believes something is wrong and begins secreting oil. When stress is applied, in this case deprivation of nitrogen, it prepares for the worst and shifts resources toward making fatty acids, which are precursors to neutral lipids like vegetable oil.

A neutral lipid has no polarity. There are different types of lipids and some of them can be used for biofuel but not others. Berberoglu wants the synthetic algae to produce neutral lipids since they make producing a good fuel source easier. An example of a non-neutral lipid, or phospholipid, would be cell membranes, which are not useful for fuel production.

One of the problems with conventional algae as an energy source is that it takes a lot of energy and water to grow. Conventional algae is grown in large, open ponds called photobioreactors. The first rule of thermo dynamics tell us that it takes more energy to make new energy from an existing source than the quantity of the end product. Because of the energy loss, the only way to make an alternative energy source economically worthwhile is to use “free” energy, such as the sun. This is known as process efficiency.

First Law of Thermal Dynamics

The first law of thermodynamics is essentially the same as the conservation of energy. Because the amount of energy in a system remains constant, it is impossible to perform work that results in an energy output greater than the energy input.

detail of synthetic algae in petri dish with very little water


two bottles of conventional algae that is mainly water

Green algae (on the left) and cyanobacteria (on the right) cultures being cultivated in the bottles use much more water than the algae grown as biofilms in the image above.

The Possibilities

When harvesting oil from conventional algae, there is a very low percentage of difference between energy in and energy out. Various processes already tested haven’t proven to be economically viable. There are many factors that determine the percent of differences, so the exact percentage is up for debate. The best scenario appears to be break-even. The new system Berberoglu and Murphy are testing appears to be six times more efficient in their indoor lab experiments. However, when the technology moves out of a lab, the results will decrease due to added variables, but they expect the output to remain greater than the input.

If you look at the different types of conventional algae in the jars shown in the photo, you will notice each one has a high percentage of water to algae. Compare that to the miniscule amount of water in the petri dish containing the synthetic variety. The water savings between the two types is obvious.

The Challenges

When Berberoglu looks at all possible sources of energy, he believes that synthetic algae poses the best alternative for a future energy source, since all the ingredients needed to make it are renewable and available. However, there are drawbacks to developing the technology, as to all energy technologies. Even the synthetic algae requires extensive land use. It would take several acres of land to produce just one quart of oil. When one compares renewable energy to oil and gas, the immediate availability and large reservoirs of oil and natural gas continue to be the easiest way to harvest and produce the massive amount of energy the world demands, but those energy reserves are not renewable. Crude oil, coal and natural gas formed in the span of millions of years. Berberoglu and Murphy need to make it in a timespan measured in days or weeks.

The 'Grand Challenges' we’re facing

Today’s scientists, engineers and politicians are facing tough choices in how we, as members of the human race, move forward. As energy demand escalates, all kinds of decisions have to be made on how we try to provide for the demand without simultaneously destroying the planet. If finding scientific answers was all that was needed to stop climate change and provide enough energy and food for the planet, it could have been controlled by now, but that is not the case. These are the Grand Challenges that the National Academy of Engineering is putting forth to future and current students, scientists, engineers, politicians and leaders to solve. It’s not going to be easy, but we owe it to ourselves and future generations to work hard, work smart, fund research and education so that we have can solve these issues. We will not be successful if we are afraid to act, to change and to grow.

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