Lignocellulose conversion of ensiled Caragana korshinskii Kom. facilitated by Pediococcus acidilactici and cellulases

To explore the biofuel production potential of Caragana korshinskii Kom., Pediococcus acidilactici and an exogenous fibrolytic enzyme were employed to investigate the fermentation profile, structural carbohydrates degradation, enzymatic saccharification and the dynamics of bacterial community of C. korshinskii silage. After 60 d of ensiling, all additives increased the fermentation quality. The highest lactic and acetic acids and lowest non-protein nitrogen (NPN) and ammonia nitrogen (NH3-N) were observed in P. acidilactici and Acremonium cellulase (PA + AC) treated silage. Additionally, all additives significantly increased the ferulic acid content and fibre degradability with the highest values obtained from PA + AC silage. The bacterial community in all silages was dominated by P. acidilactici throughout the entire fermentation process. The bacterial community was also modified by the silage additives exhibiting a relatively simple network of bacterial interaction characterized by a lower bacterial diversity in P. acidilactici (PA) treated silage. The highest 6-phospho-beta-glucosidase abundance was observed in PA-treated silage at the mid-later stage of ensiling. PA treatment exhibited lower structural carbohydrates degradation but performed better in lignocellulose conversion during enzymatic saccharification. These results indicated that pretreating C. korshinskii improved its silage quality and potential use as a lignocellulosic feedstock for the production of bio-product and biofuel.

Automated summary

Pediococcus acidilactici and an exogenous fibrolytic enzyme were used to improve the fermentation quality and lignocellulose conversion of Caragana korshinskii silage. The addition of P. acidilactici and Acremonium cellulase (PA + AC) resulted in the highest lactic and acetic acids, lowest non-protein nitrogen and ammonia nitrogen levels. The bacterial community in all silages was dominated by P. acidilactici, and the addition of P. acidilactici led to a simpler network of bacterial interaction and lower bacterial diversity. PA treatment exhibited lower structural carbohydrates degradation but performed better in lignocellulose conversion during enzymatic saccharification. These findings suggest that pretreating C. korshinskii with PA can improve its silage quality and make it a potential feedstock for bio-product and biofuel production.