SBIR Phase I: Large Scale Cultivation of Phytoplankton via Novel Photo-Bioreactor Technology

The broader impact/commercial potential of this Small Business Technology Transfer (STTR) project will be to develop a sustainable, low-cost, and replicable method for large-scale production of micro-algal biomass. Microalgae production is a form of aquaculture capable of producing valuable products including nutraceuticals, specialty chemicals, pharmaceuticals, feed for finfish, shellfish, and livestock, as well as food for human consumption. Moreover, it can be used as a feedstock for biofuels while simultaneously removing CO2 from the environment. However, for algae cultivation to achieve its full commercial potential, the technology must be improved. While typical algal cultivation relies on high-density cell growth, this project will focus on the science of low-density algal cultivation to achieve high productivity, while minimizing process requirements for supplemental energy and concentrated CO2. In addition, the development of a closed-system photo-bioreactor with emphasis on low cost and modular design will allow the process to be easily replicated across the country on a variety of lands with otherwise marginal value. As such, the system can become the basis for a robust aquaculture and biofuels industry, leading to greater economic development in marginal communities and a source of sustainable products for the growing world population. This STTR Phase I project proposes to develop a large-scale algal production system. Current methods of large-scale microalgae production are limited by technological problems, which prevent them from being reliable and scalable. These problems include frequent contamination, low productivity, and increased operating costs due to inefficient use of water and energy. The goals for our system are to maintain a low-density algal culture with high productivity for greater than two months without contamination, while requiring little or no additional cooling and CO2 supplementation. With the use of a specially designed harvest apparatus, the plan is to perform periodic harvest cycles in order to maintain the culture in a low-density state. Using gravity settling, the biomass will be concentrated by a factor of 100x prior to removal in order to minimize the loss of water from the system. To characterize the performance of the system, cell growth rate, batch temperature, pH, and dissolved CO2 levels will be monitored. Nitrogen/CO2 sparging tests will be used to determine the gas-liquid mass-transfer coefficient of the reactor. Productivity rates will be compared with and without the supplementation of concentrated CO2, and culture purity will be assed daily via microscopy checks.