Effects of Fe/Mg-modified lignocellulosic biochar on in vitro ruminal microorganism fermentation of corn stover

This study investigated the effectiveness and synergistic mechanism of trace-element-modified biochar (BC) on in vitro ruminal fermentation of lignocellulose. Fe/Mg-modified BC containing Fe@BC, Mg@BC and Fe/Mg@BC were prepared, and their effects on in vitro ruminal fermentation of corn stover were assessed. Results indicate that Mg@BC achieved the highest reducing-sugar content (320.4 mg/L) with an additive dose of 12 g/L and a substrate load of 4 %, owing to the presence of enriched lignocellulolytic microorganisms like Treponema and Bacillus. Moreover, Mg@BC promoted the growth of acid-producing bacteria, including Bacteroides and Lachnospiraceae, resulting in the highest production of volatile fatty acid (3.2 g/L). Fe@BC increased the amount of hydrogenogens including Prevotellaceae_YAB2003 and Lachnospiraceae_NK3A20, contributing to the highest hydrogen production. Meanwhile, Fe/Mg@BC facilitated the growth of Succiniclasticum and Lactobacillus, which effectively produce succinic and lactic acids. These findings provide new insights into efficient lignocellulose bioconversion via in vitro ruminal fermentation with Fe/Mg-modified BC supplementation.