The system provides a way to tailor anaerobic gut fungi fermentations without the use of genetic tools.
The Science: Anaerobic gut fungi (AGF) are found in the digestive tracts of large herbivores. These fungi have the potential to turn lignocellulosic biomass into useful products, including sugars for microbial upgrading into fuels, chemicals, and materials such as apparel, diapers, and toys. They have a diverse array of enzymes that can free sugars from biomass and directly produce hydrogen, ethanol, and short-chain fatty acids. However, AGF metabolism is poorly understood. There are also no genetic tools that can manipulate them to enhance the production of specific targets. To address this, researchers developed an inexpensive bioreactor system that can effectively tune the AGF Caecomyces churrovis in order to increase production.
The Impact: The researchers developed a bioreactor system that allows them to probe metabolism and predictably tune fluxes in C. churrovis. Using this system, they were able to alter certain process parameters, which in turn controlled the growth rate, metabolic flux, and production rates. The system also enabled them to achieve faster AGF growth rates. The methods they demonstrated provide a way to tailor AGF fermentations without the use of genetic tools. This will help scientists better understand AGF so they can use it for industrial bioproduction.
Summary: The researchers developed an Arduino-based continuous flow bioreactor for continuous culture of anaerobic fungi. The system, which can be assembled for under $400, contains a sensor that samples the culture every 300 milliseconds. The bioreactor also has the ability to identify the required dilution rate and hold it constant. This system can be leveraged to tune product profiles for bioproduction of carbohydrate-active enzymes, lactate, formate and/or acetate.
Publication: Leggieri, P., Blair, E., Lankiewicz, T., et al. Continuous culture of anaerobic fungi enables growth and metabolic flux tuning without use of genetic tools. Bioresource Technology (2023). [DOI: 10.1016/j.biortech.2023.129854]
Written by Emily Nelson