DEVELOPMENT OF A SCALABLE CULTIVATION SYSTEM FOR SUSTAINABLE PRODUCTION OF ALGAL BIOFUELS

摘要

Algae are a promising source of renewable jet and diesel fuels and can play a significant role in climate change mitigation as a low-carbon fuel source. Currently, most industrial microalgae cultivation systems are open ponds because of their low capital and operating costs, but they suffer from low biomass productivity and high risk of contamination. We describe the development of a novel, cost-effective, and modular horizontal bioreactor (HBR) for algae cultivation. It was designed and engineered to keep costs low, while minimizing water and energy use and enhancing CO_2 and nutrient uptake. The selected marine microalgal strain, Nannochloris oculata, has shown potential for biofuels production. Algal growth was first optimized indoors before testing the HBR performance outdoors under real-world conditions. The indoor study showed that urea and potassium nitrate yield comparable results, when used as nitrogen source, whereas ammonium chloride was less effective. Varying inoculum size from 10% to 15% to 20% (v/v) had no effect on lag time, so the lowest level was selected. The 150-L HBR prototype was tested outdoors with N. oculata using the indoor optimal conditions. High-density growth was consistently achieved in the HBR without contamination problems over extended periods of time outdoors in central Florida.