Effects of Fe₂O₃ nanoparticles on lignocellulose bio-oxidation and heat production during aerobic fermentation of corn stover

During the fermentation process, heat production directly impacts the fermentation efficiency. Efficient hydrolysis of lignocellulose, as well as complete oxidation of hydrolysis products is critical for heat production during aerobic fermentation of lignocellulosic biomass. This study systematically demonstrates that Fe₂O₃ nanoparticles (NPs) enhance heat production in lignocellulose bio-oxidation during corn stover fermentation through synergistic effects between reactive oxygen species (ROS) generation and microbial community restructuring, thereby optimizing fermentation efficiency and shortening fermentation cycles. Specifically, Fe₂O₃ NPs facilitated Fenton-like redox cycling to generate ROS, thereby creating accessible enzymatic reaction sites and accelerating lignocellulose degradation. Additionally, ROS-induced oxidative stress triggered microbial metabolic flux redistribution, directing more glucose toward catabolic pathways to sustain cellular metabolism, thereby improving glucose oxidation efficiency and associated heat output. Results showed that Fe₂O₃ NPs enhanced organic matter degradation by maintaining a high abundance of Bacillota, thereby optimizing the functionality of microbial community. In presence of Fe₂O₃ NPs, cellulose degradation rate reached 42.53 % within 30 days, representing a 13.60 % increase compared to the control group (CK). Furthermore, Fe₂O₃ NPs treatment achieved a peak heat production rate of 2.25 W/kg, which was 15.38 % higher than CK. Compared with Fe₂O₃ NPs, Fe₂O₃ submicron particles were less efficient in synergizing with microorganisms due to their restricted specific surface area, which resulted in a lower heat production rate. These findings highlight the potential of incorporating Fe₂O₃ NPs into agricultural waste aerobic fermentation systems as a viable strategy to enhance resource utilization efficiency.