Miscanthus accessions distinctively accumulate cadmium for largely enhanced biomass enzymatic saccharification by increasing hemicellulose and pectin and reducing cellulose CrI and DP

摘要

In this study, total eight distinct Miscanthus accessions were collected from the cadmium (Cd)-supplied soil pots, and mild alkali pretreatments (0.5%, 1% NaOH) were then performed to enhance biomass enzymatic saccharification. Due to large Cd accumulation, all Miscanthus accessions showed significantly reduced cellulose levels and features (CrI, DP) with much increased hemicellulose and pectin contents in the mature stems. Under mild alkali pretreatments, all Miscanthus samples exhibited largely increased hexoses yields released from enzymatic hydrolysis, and one desirable accession had an almost complete biomass saccharification with the hexoses yield at 100% (% cellulose). Notably, the biomass residues remained from enzymatic hydrolysis upon 1% NaOH pretreatment could absorb 73-96% Cd (% of total), suggesting an applicable approach for Cd phyto-remediation. Hence, a hypothetic model was proposed to elucidate that the enhanced biomass saccharification should be mainly due to much reduced cellulose CrI and DP in the Cd-accumulated Miscanthus accessions.