EFRI-PSBR: Integrated design of cyanobacterial biorefineries

Colorado State University, Fort Collins CO

Investigators

Abstract

Abstract Intellectual Merit: Several novel systems approaches and an alternative target biofuel are brought to bear in this project to develop sustainable processes for the production of fuels and chemicals by cyanobacteria. The project has been awarded to a multidisciplinary team, consisting of Professors Kenneth F. Reardon, David S. Dandy, Thomas H. Bradley, Christie A.M. Peebles, and Graham Peers, all of Colorado State University, Fort Collins, CO. To address the goals of increasing commodity yields and increasing the sustainability of photosynthetic microbe-derived fuels, the research team will synthesize knowledge and approaches from fluid dynamics, photosynthetic physiology, proteomics, metabolic engineering, and life cycle analysis methods. In a novel approach to engineer photosynthetic efficiency, the team will model the environment of different photobioreactors and use these models to design accurate scale-down systems for laboratory cultivations, opposite to the usual practice. This will allow them to identify and target industrially relevant biology at a small scale and make accurate predictions for large-scale systems. Next, the team will quantify energy losses and stresses associated with photosynthesis, and target these for genetic improvements. This genetic research will be coupled to the metabolic engineering of cyanobacteria to shuttle carbon to a novel sesquiterpene fuel molecule, bisabolene, which offers promise as an alternative biodiesel which does not require transesterification processing, necessary in the current biodiesel production from vegetable oils. To separate the cyanobacterial cells from their cultivation liquid in an energy-efficient manner, the team will develop a novel inertial migration-based cell concentration mechanism. All of these studies on system performance will be guided by feedback from new life cycle analysis methods developed by modeling the productivity of large-scale reactors using the scale-up relationships developed in this project. The Colorado State team predicts this integrated approach to solving the major issues associated with photosynthetic microbe-based fuels will result in a rapid increase in the accuracy and speed with which the productivity of the system can be manipulated; greater yields of target molecules in industrial deployment; large, quantified increases in the overall sustainability of the process; and transferrable approaches toward the cultivation of photosynthetic microbes and the production of other biofuels or biochemicals. Broader Impacts: The proposed work, which encompasses understanding of photobioreactor process dynamics, physiological responses of cyanobacteria to photobioreactor conditions, engineering of cyanobacteria to produce biofuels and biochemicals, and life cycle analysis, will lead to photosynthetic production of advanced biofuels and biochemicals with the potential to be environmentally sustainable. The engineered strains will serve as a platform for future research on biofuel upgrading strategies and on biochemical production strategies. The project will provide interdisciplinary training for undergraduate and graduate students, as well as postdoctoral scholars, with significant efforts being made to include members of underrepresented groups. Students will gain broad experience in modeling, metabolic engineering, systems biology, microbial cell cultivation of photosynthetic organisms and life cycle analysis, placing the students at the forefront of research in biofuel production from photosynthetic organisms. The project includes opportunities for mentoring of K-12 students in research, as well as teacher training. The results of this project will be disseminated in leading peer-reviewed journals, national meetings, in new courses, and via an interactive website.