Effect of alkali salt-coupled ball milling pretreatment of wheat straw on improving enzymatic hydrolysis and energy efficiency

Pretreatment of lignocellulosic biomass is crucial in producing fermentable sugars in a sustainable biorefinery. In this study, wheat straw was pretreated with a combination of ball milling (BM) and NaAlO2 particles (NaAlO2- BM) for enzymatic hydrolysis within a short hydrolysis period. The effects of energy consumption on modifi-cations of physicochemical proprieties and energy efficiency were elucidated. NaAlO2-BM pretreatment decreased particle size rapidly to tissue scale in 10 min with energy consumption reduced by 0.5 times compared to BM pretreatment. NaAlO2-BM pretreated for 20 min achieved a glucose yield of 95.4% at a cellulase loading of 10 FPU/g dry substrate for 24 h enzymatic hydrolysis and provided the highest energy efficiency of 0.121 kg glucose/kWh, increasing by 1.1 times than BM pretreatment. Energy consumption showed a positive relationship with cellulose content while it negatively correlated with median particle size, cellulose crystallinity and energy efficiency. The combination of BM and NaAlO2 particles was demonstrated to be a promising pretreatment approach for glucose production and improving energy efficiency during hydrolysis of lignocellulose.

Automated summary

In this study, wheat straw was pretreated with a combination of ball milling (BM) and NaAlO2 particles (NaAlO2-BM) for efficient enzymatic hydrolysis. The results showed that NaAlO2-BM pretreatment significantly reduced particle size to tissue scale within 10 minutes, with 0.5 times lower energy consumption compared to BM pretreatment. The 20-minute NaAlO2-BM pretreatment achieved a glucose yield of 95.4% and the highest energy efficiency of 0.121 kg glucose/kWh, increasing by 1.1 times than BM pretreatment. Energy consumption was positively correlated with cellulose content and negatively correlated with particle size, cellulose crystallinity, and energy efficiency. The combination of BM and NaAlO2 particles proved to be a promising pretreatment approach for glucose production and improving energy efficiency during lignocellulosic hydrolysis.