Cyanobacterial Physiology, Cell Biology, and BiochemistryCyanobacteria cultures, chlorophyll a fluorescent, and schematic of photosynthesis

Sub-cellular organization of bacterial metabolism

Bacterial metabolism is highly organized in space and time. This spatial and temporal organization of metabolism enables multiple, often competing, reactions to occur simultaneously in the same cell. While subcellular organization in the form of membrane-bound organelles has become the paradigm for eukaryotes, the cellular complexity of bacteria and the inherent relationship to metabolism is only beginning to be appreciated. To unlock the true potential of synthetic biology and design novel microbial systems, signaling pathways and metabolic networks, the subcellular environment must be considered. Thus, our research is focused on using synthetic biology to understand native principles of cellular organization and design novel subcellular architectures for controlling metabolic networks in microbial systems. Cyanobacteria are major primary producers and are unique in their ability to perform oxygenic photosynthesis, nitrogen fixation, and CO2 fixation; these reactions are naturally optimized through spatial and temporal separation. These attributes make cyanobacteria ideal subjects for the modulation of cellular architecture and metabolism.


Ancestors of modern day cyanobacteria were the first to perform oxygenic photosynthesis. These reactions have changed the atmospheric composition of this planet and have dramatically shifted the evolutionary trajectory of earth’s inhabitants. In cyanobacteria, the photosynthetic electron transfer complexes are located in the thylakoid membrane system. We are interested in understanding the spatial and temporal organization of photosynthesis in cyanobacteria. Because photosynthesis provides the building blocks for the generation of food, fuel, green chemicals, and other useful products essential for life on earth, understanding how photosynthesis is regulated and identifying potential routes for improvement will benefit society and the environment.

CO2 fixation

Cyanobacteria play critical roles in the global carbon cycle and are attractive biological catalysts that can convert CO2 into useful products in support of a green-economy for the benefit of society and the environment. All cyanobacterial carbon fixation occurs within the carboxysome, a specialized protein-based organelle containing the enzymes RuBisCO and carbonic anhydrase that functions as the centerpiece of the highly efficient CO2-concentrating mechanism (CCM). These organelles, shaped like an icosahedral virus capsid, are organized as discrete particles within the cell and are essential for growth at current atmospheric CO2 concentrations. We use long-term time-lapse microscopy, quantitative image analysis, and an array of biochemical and biophysical techniques to investigate the function and assembly of carboxysomes and related bacterial microcompartments in single-cells and bacterial populations. The video (From: Cameron et al. Biogenesis of a bacterial organelle: The carboxysome assembly pathway. (2013). Cell 155: 1131-1140) below shows the assembly of carboxysomes (green) in cyanobacterial cells (red).