A win-win solution
Harvesting the power of microbial-based energy sources
Perhaps there is no greater societal need for scientific know-how than to find new ways to meet future energy demands. Skyrocketing gas prices, an uncertain oil supply, increasing demand from around the world, and the looming threat of climate change have made identifying and developing realistic energy alternatives a national priority.
Microorganisms once reigned supreme on the Earth, thriving by filling every nook and cranny of the environment billions of years before humans first arrived on the scene. Now, this ability of microorganisms to grow from an almost infinite variety of food sources may play a significant role in bailing out society from its current energy crisis, without damaging the environment or competing with our food supply.
What is it about bacteria that make them an attractive tool for bioenergy research? Consider that one species of bacteria, the human gut bacterium E. coli, has become the workhorse of the multi-trillion dollar global biotech industry. Might other unearthed microbial treasures have the same potential in bioenergy applications?
Unlike the E. coli situation, using just one species may not work well for bioenergy, since, in nature, bacteria do not grow in isolation. In other words, no bacterium is an island. The very biodiversity that fills the Earth with bacteria and offers great bioenergy potential also presents a challenge for engineers. Even if one picks the ideal “bug,” growing, maintaining, and optimizing conditions for its use in bioenergy applications remains a daunting challenge in terms of scalability and reliability.
Microbial communities that are used to harvest energy must be resilient to fluctuations in environmental conditions, variations in nutrient and energy inputs and intrusion by microbial invaders that might consume the desired energy product. The key to large-scale success in microbial bioenergy is managing the microbial community so that that the community delivers the desired bioenergy product reliably and at high rate.
Two distinct, but complementary approaches will be needed. The first is to use microbes to convert biomass to useful energy. Different microorganisms can grow without oxygen to take this abundant organic matter and convert it to useful forms of energy such as methane, hydrogen, or even electricity. In addition, different non-photosynthetic microorganisms can grow without oxygen and take abundant organic waste matter, converting the energy value of all kinds of biomass, including wastes, into readily useful energy forms, such as methane, hydrogen, and even electricity.
The second approach uses bacteria or algae that can capture sunlight to produce new biomass that can be turned into liquid fuels like biodiesel, or converted by other microorganisms to useful energy. Photosynthetic bacteria can capture sunlight energy at rates 100 times or greater than plants, and they do not compete for arable land. This high rate of energy capture means that renewable biofuels can be generated in quantities that rival our current use of fossil fuels.
Both approaches currently are intensive areas of biofuel research at the Biodesign Institute.
In the absence of these molecular techniques, our understanding of methanogenic communities progressed through slow, incremental advances over several decades. Today, society cannot wait decades for new bioenergy sources.