Innovative Strategy to Enhance Bioconversion of Sweet Sorghum Bagasse (SSB) by the Combination of Bio-Fortified Ensiling and Dilute Alkali Pretreatment

The characteristics of seasonal-harvesting and recalcitrance to biodegradation hinder the efficient bioenergy utilization of biomass. To overcome the drawbacks, it’s necessary to develop an integrated strategy for ensiling preservation to improve the bioconversion of lignocellulosic biomass. In this study, sweet sorghum bagasse (SSB) was ensiled for 21 days, followed by diluted NaOH pretreatment to enhance the biodegradability. Compared with the raw SSB and non-biofortified silage, the bio-fortified ensiling with L. plantarum alone or both L. plantarum and fibrolytic enzyme promoted the degradation of lignocellulose (e.g., hemicellulose, lignin) of SSB. Based on the membership function, L. plantarum additives was the most efficient for the improvement of ensiling quality. The genus of Lactobacillus (3.91–40.45%), Enterobacteriaceae (11.63–38.58%), and Pantoea (8.21–28.01%) were dominant at 21 days, accompanied by the high content of lactic and acetic acid in different silages. Moreover, Lactobacillus was beneficial to ensiling quality. Comparing to raw SSB (40.91%), the enzymatic efficiency of SSB sharply increased to 88.52% by the combination pretreatment of bio-fortified ensiling with L. plantarum and subsequent 2% NaOH, which was the most economical pretreatment method. In short, this work proposes a promising strategy by combining bio-fortified ensiling and NaOH pretreatment for the storage and bioenergy production of SSB.