Bioprocesses with open cultures of microbial consortia (reactor microbiomes, similar to gut microbiomes) are advantageous for waste processing because they remain functionally stable during invasions of outside microbes, circumventing costs for influent sterilization. Under anaerobic conditions (without oxygen), these microbiomes have been mainly used in anaerobic digesters to convert organic wastes into methane as an energy carrier. However, methane is a relatively low-cost commodity. This research project will examine whether urban wastes, such as food and wood wastes, can be converted into a longer-carbon-chain biochemical with multiple uses as a more valuable commodity. The production of longer-chain biochemicals was observed with an enriched reactor microbiome that was able to produce mainly one soluble product (n-caproic acid) from a complex organic substrate. The investigator was able to shape the microbiome by controlling the temperature and pH while continuously extracting the chemical product from the bioprocess during the operating period. This study will focus on functional and microbial population stability during application of the technology to urban wastes, which include: (1) an increase in extraction rates of the biochemical; and (2) perturbations of the waste quality that are common for real waste treatment systems. Besides long-term bioreactor studies that include perturbation experiments, the PI will use a combination of several high-throughput molecular biology techniques. These techniques provide a unique picture of the dynamics of specific microbial populations as well as their metabolic activities in the microbiomes.
This project will advance the scientific knowledge about biochemical and biofuel production using microbiomes. The research also should shed light on how microbial populations behave in a microbiome over the long operating periods of bioprocesses that treat real urban wastes during high rate extraction of final biochemical fermentation product. The results will also investigate whether biochemical and biofuel production can be performed in a stable way with reactor microbiomes rather than just with pure cultures. The bioprocessing application and its challenges will be discussed in a new hands-on workshop for local high school students at the university campus.
