Lignocellulose usually requires pretreatment to improve biogas production. To enhance lignocellulose biodegradability and improve anaerobic digestion (AD) efficiency, different types (N₂, CO₂, and O₂) of nanobubble water (NW) were applied in this study as soaking agent and AD accelerant to increase the biogas yield of rice straw. The results showed that the cumulative methane yields of treating with NW in two-step AD increased by 11.0%–21.4% compared with untreated straw. The maximum cumulative methane yield was 313.9±1.7 mL/gVS in straw treated with CO₂-NW as soaking agent and AD accelerant (P_CO2-M_CO2). The application of CO₂-NW and O₂-NW as AD accelerants increased bacterial diversity and relative abundance of Methanosaeta. This study suggested that using NW could enhance soaking pretreatment and methane production of rice straw in two-step AD; however, combined treatment with inoculum and NW or microbubble water in the pretreatment needs to compare in future.

木质纤维素通常需要预处理以提高沼气产量。为了提高木质纤维素的生物降解性和厌氧消化（AD）效率，本研究采用不同类型（N ₂、CO ₂和O ₂ ）的纳米气泡水（NW）作为浸泡剂和AD促进剂来提高水稻的沼气产量稻草。结果表明，与未处理的秸秆相比，在两步厌氧消化中使用 NW 处理的累积甲烷产量增加了 11.0% ~ 21.4%。以CO ₂ -NW为浸泡剂和AD促进剂(P _CO2 -M _CO2 )处理的秸秆最大累积甲烷产量为313.9±1.7 mL/gVS。_{CO 2} -NW和O ₂的应用-NW 作为 AD 促进剂增加了甲烷菌门的细菌多样性和相对丰度。本研究表明，使用 NW 可以提高水稻秸秆在两步厌氧消化中的浸泡预处理和甲烷产量；但是，在预处理中采用接种物和NW或微泡水联合处理需要在未来进行比较。