Role of Fungi in the Biofiltration of Livestock Housing and Manure Storage Emissions

Abstract

Biofilters use porous media colonized by microbial biofilms to capture and degrade odorous, hazardous and greenhouse gases making them well-suited for livestock housing and manure storage emissions. Fungi are abundant in these biofilters though their dynamics, degradation of media, community shifts, and functional roles have not been well-investigated. To explore spatial and temporal fungal dynamics in full-scale woodchip biofilters treating swine barn emissions, a novel monitoring approach was developed. Using wooden baits and microbial measures optimized to target biofilms biofilter fungi were characterized and shown to tolerate media desiccation. Additionally, successional patterns at the taxa and guild level were studied, and the development of a dominant fungal community was identified. To address the practical question of media longevity, a litter bag study was deployed in the same full-scale biofilters. Decay rates of various media types were identified, and microbial decay was dependent on media quality, nitrogen, and emissions levels. Using a lab-scale biofilter system, fungi were shown to improve the capture of methane, particularly after periods of low-concentration inlet emissions. Using a chromatographic isotherm the ability of fungi to sorb methane gas was verified for the first time. Collectively, this work showcases dynamics and potential abilities of fungi in biofilters treating livestock production emission and may be used to guide subsequent efforts to connect fungi to biofilter function. If these processes can be understood and controlled, there is the potential to improving biofilter performance, better protect air quality and improve farming system sustainability.