Employing microbes as sources of sustainable biofuels

ScientistLive
Date: 23/07/2008

Considering the prevalence, durability, and efficiency of microbes, the notion of utilising the microscopic organisms as a means of generating sustainable energy sounds too good to be true. In a new issue on "microbial ecology and sustainable energy" in the journal Nature Reviews Microbiology, the Bruce Rittman and his fellow Biodesign Institute researchers outline paths where bacteria are the best hope in producing renewable energy in large quantities without damaging the environment or competing with our food supply.

Dr. Rittman took time out to speak with Scientist Live about the exciting research being conducted at the institute.

By what means/mechanisms can microbes play a role in producing usable, sustainable energy?

They can do it in two ways that are complementary. In the first way, communities of anaerobic bacteria convert the energy value (contained in electrons) of biomass into socially useful bioenergy forms: methane (natural gas), hydrogen gas, or electricity. The biomass can be wastes from agriculture, animals, industry (like food), and humans (sewage). In this case, the capturing of the bioenergy also is a means to remove the pollution in the waste material. In addition, the biomass could be made especially for being a bioenergy source, which leads to the second way. In the second way, photosynthetic microorganisms capture sunlight energy through photosynthesis to make more of themselves. The microorganisms can be algae or photosynthetic bacteria, also called cyanobacteria for their blue-green colour. In our team, we use cyanobacteria. Some of the photosynthetic microbes contain a high proportion of lipids, or oils, that can be used a a feedstock for liquid fuels, such as biodiesel. The non-lipid portions constitute biomass for feeding into the first way for energy conversion.

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