Miscanthus straw as substrate for biosuccinic acid production: Focusing on pretreatment and downstream processing

The main aim of this study was to optimize pretreatment strategies of Miscanthus × giganteus for biosuccinic acid production. A successful pretreatment with organosolv method (80% w/w of glycerol, 1.25% of H₂SO₄), prevented sugars conversion to furfurals and organic acids, and thereby resulted in high sugar recovery (glucan > 98%, xylan > 91%) and biomass delignification (60%). Pretreated biomass was subjected to hydrolysis with various cellulolytic enzyme cocktails (Viscozyme® L, Carezyme 1000L®, β-Glucanase, Cellic® CTec2, Cellic® HTec2). The most effective enzymes mixture composed of Cellic® CTec2 (10% w/w), β-Glucanase (5% w/w) and Cellic® HTec2 (1% w/w) resulted in high glucose (93.1%) and xylose (69.2%) yields after glycerol-based pretreatment. Succinic acid yield of 75-82% was obtained after hydrolysates fermentation, using Actinobacillus succinogenes 130Z. Finally a successful downstream concept for succinic acid purification was proposed. The succinic acid recovery with high purity (>98%) was developed.