Unlocking the bioreactor microbiome for nutrient management and water quality

Sep 2022


Currently, the bioreactor microbial community is a black box of uncertainty in terms of what is responsible for the denitrification and pollution swapping and where the community is originating from. Preliminary data from researchers’ prior work compared woodchips from nine field bioreactors operating for two years at different flow conditions and identified consistent microbial membership between the installed bioreactors as well as consistent load reduction across the range of controlled hydraulic retention times. These observations, that predictable microbes were associated with bioreactors with varied engineered controls, are the rationale for the hypothesis that bioreactor microbiomes can be selected and may also be managed. Researchers believe that understanding how the environmental conditions affect both nutrient removal and the microbiome will benefit bioreactor performance and ensure the sustainability of their operations.


In this proposal, researchers seek to identify and manipulate microbial communities in corncob and woodchip bioreactors that mediate complete denitrification of nitrate to dinitrogen gas, with minimal release of nitrous oxide, methane or methylmercury to expand the full potential of this conservation practice. Further, treating bioreactor microbial communities as manageable resources, they will evaluate the feasibility of managing and manipulating bioreactor microbiomes to benefit bioreactor performance.  


The researchers will use the data collected to develop a model, which will be the first to link operation, microbiome and function, and will support understanding of the underlying biological and chemical controls for integrating this conservation practice in agroecosystems.

Award Number: 

Project Updates

Note: Project reports published on the INRC website are often revised from researchers' original reports to increase consistency.

December 2022

Researchers recruited a graduate student to help lead this research. An in lab-scale representation of bioreactors has been constructed. Fresh woodchips have been collected to be placed inside the three designed up-flow columns. The microbiome associated with these woodchips will be characterized through DNA extraction of woodchip surfaces. Quality control is completed, and the bioreactor laboratory design is now operational.  Standard procedures are being developed for water sample collection, greenhouse gas sample collection and DNA sample collection and extraction techniques. Experiments are scheduled to begin in mid-January.