Understanding and Enhancing Microbial Lipid Production for Biofuels
Lipids derived from oil-rich microorganisms such as bacteria, yeast, and microalgae offer a promising source of renewable fuels and chemicals. However, genetic and biochemical mechanisms regulating lipid accumulation in microorganisms are poorly understood. A recent study revealed a novel molecular pathway involved in microbial lipid accumulation. Researchers from the Department of Energy’s (DOE) Great Lakes Bioenergy Research Center (GLBRC) and the University of Wisconsin-Madison used the cryotransmission electron microscope at the DOE Environmental Molecular Sciences Laboratory to study lipid accumulation in the microbe Rhodobacter sphaeroides. Using fatty acid levels to assess membrane lipid content, the team found that the total fatty acid content per cell increased three-fold under low oxygen and anaerobic conditions compared to high oxygen conditions. They also found that the microbes’ lipid and pigment accumulation processes were separable, and they identified a transcription factor called PrrBA that is required for fatty acid accumulation in response to low oxygen levels. This new approach to maximize lipid production through an alteration in the activity of a single transcriptional regulator could lead to the development of strategies for engineering this microbe to increase yields for large-scale production of lipids for biofuels and chemicals.
Lemmer, K. C., A. C. Dohnalkova, D. R. Noguera, and T. J. Donohue. 2015. “Oxygen-Dependent Regulation of Bacterial Lipid Production,” Journal of Bacteriology, DOI: 10.1128/JB.02510-14.