Simulating Rumen Conditions Using an Anaerobic Dynamic Membrane Bioreactor to Enhance Hydrolysis of Lignocellulosic Biomass

Abstract

An anaerobic dynamic membrane bioreactor (AnDMBR) mimicking rumen conditions was developed to enhance the hydrolysis of lignocellulosic materials and the production of volatile fatty acids (VFAs) when treating food waste. The AnDMBR was inoculated with cow rumen content and operated at a 0.5 day hydraulic retention time, 2−4 day solids retention time, a temperature of 39 °C, and a pH of 6.3, characteristics similar to those of a rumen. Removal rates of neutral detergent fiber and acid detergent fiber of 58.9 ± 8.4 and 69.0 ± 8.6%, respectively, and a VFA yield of 0.55 ± 0.12 g VFA as chemical oxygen demand g volatile solids (VS) fed −1 were observed at an organic loading rate of 18 ± 2 kg VS m −3 day −1 . The composition and activity of the microbial community remained consistent after biofilm disruption, bioreactor upset, and reinoculation. Up to 66.7 ± 5.7% of the active microbial populations and 51.0 ± 7.0% of the total microbial populations present in the rumen-mimicking AnDMBR originated from the inoculum. This study offers a strategy to leverage the features of a rumen; the AnDMBR achieved high hydrolysis and fermentation rates even when treating substrates different from those fed to ruminants.

Top-down and bottom-up microbiome engineering approaches to enable biomanufacturing from waste biomass

“…For instance, the rumen is an example of a natural microbial ecosystem that harbors diverse microbial populations (bacteria, methanogenic archaea, fungi, and protists), which can naturally break down recalcitrant lignocellulosic biomass (Hess et al., 2011 ; Gilmore et al., 2019 ; Liang et al., 2020 ). Several efforts have been made to harness rumen-derived mixed microbial communities or mimic such microbial ecosystems in engineered anaerobic systems, leveraging the physiochemical, and biological characteristics of rumen to achieve significant degradation of lignocellulose (Fonoll et al., 2021 , 2024 ).…”