Effects of cold isostatic press pretreatment of rice straw on microstructure and efficiency of anaerobic digestion for methane production

In this study, rice straw (RS) was pretreated using cold isostatic pressure (CIP) to disrupt the microstructure of RS and improve the performance of anaerobic digestion (AD). Optimisation of key parameters by applying response surface methodology showed that conditions at 400 Mpa and a holding time of 9 min were optimal for methane production, and validation experiments were carried out to verify the optimal conditions. The results show that CIP pretreatment can effectively disrupt the structure of RS and improve the biodegradability of RS. The cumulative methane production from CIP pretreatment increased by 75.95% compared to the untreated RS. Microbial community analysis showed that the relative abundance of Firmicutes, Halobacterota, DMER64 and Methanosaeta was higher in AD pretreated with CIP than in conventional AD. This study demonstrates the feasibility of using CIP pretreatment as an effective pretreatment method to promote methane production during AD.