Analysis and Engineering of Feedstocks for Industrial Bioprocesses

摘要

Biological production of fuels and chemicals has been a popular area of research for decades. The potential for producing valuable fuels and chemicals, typically supplied from petroleum sources, using renewable feedstocks is attractive both economically and environmentally. As our long-term survival on this planet is determined by our ability to manage our resources carefully, the use of biological production methods will become critical. In this body of work, we study the feedstocks used to power industrial bioprocesses. First, we show the economic impact of replacing glucose with methane, methanol, or acetate as a carbon source. Methane and acetate both have promise as replacements for glucose, but both may have technical hurdles to implementation. Under current market prices, methanol is not an economically viable replacement for glucose. Next, we study the potential of the marine cyanobacterium, Synechococcus sp. strain PCC 7002, to act as the primary glucose source for industrial bioprocesses. Cyanobacteria have higher biomass productivity than terrestrial plants, do not require arable land, and do not compete with food sources. We show the ability to improve the accumulation of glycogen, a glucose polymer, under diurnal growth conditions and improve understanding of how nitrogen starvation relates to glycogen production. We then approach replacing expensive fertilizers with municipal wastewater to reduce cyanobacterial growth costs. Wastewater contains compounds that are toxic to S. PCC 7002, which limits its use as a nutrient source. We show an approach to refactor wastewater media to sustain robust cyanobacterial growth. Finally, we constructed and tested an open raceway pond, which mimics industrial-scale facilities. The data from each Chapter was combined to produce a technoeconomic analysis that describes the cost of producing cyanobacterial biomass containing high glycogen content on an industrial scale. We show that the improvements in glycogen production, biomass production, and wastewater tolerance decrease the cost of growing cyanobacteria by nearly 30%.