A meta-analysis for effects of pretreatments on corn straw for methane production

Anaerobic digestion (AD) is an effective approach for achieving sustainable utilization of corn straw (CS) and promoting the development of circular economy. Pretreatment has been widely applied for AD to accelerate the solubilization of lignocellulosic components and enhance the hydrolysis rate. However, the pretreatment effects from the relevant literature are completely different, even for the same substrate and pretreatment technology, which results in a significant obstacle in determining the optimal pretreatment method for AD. To find the best pretreatment method for CS, this study performed a meta-analysis with 397 data extracted from 47 published studies to explore the impacts of different pretreatments on methane production of CS. The overall results of the meta-analysis showed that pretreatment significantly enhanced the methane production performance of CS with the mean effect size of 0.178. Notably, thermal-alkali-sonication, alkali-steam explosion, and alkali pretreatment exhibited significant advantages in CS anaerobic conversion, resulting in increases of 61.0 %, 49.1 %, and 34.9 % in methane production, respectively. The biological pretreatment performance was less favorable, and did not significantly impact methane production. This study not only establishes a reliable scientific basis for choosing the optimal pretreatment methods for CS, but also lays the foundation for engineering selection of pretreatment processes.