ANHYDROUS HYDROGEN-FLUORIDE SACCHARIFICATION OF LIGNOCELLULOSIC MATERIALS .2. ENZYMATIC SACCHARIFICATION OF HOLOCELLULOSE TREATED WITH ANHYDROUS HYDROGEN-FLUORIDE

Softwood and hardwood holocelluloses were treated with anhydrous hydrogen fluoride (HF) at 20-degrees-C for 0.5-1.5 hr to determine the conditions suitable for pretreatment before enzymatic saccharification. More than 80% of the holocelluloses were converted into water-soluble products by HF treatment. The products were a mixture of mono-, oligo- and polysaccharides. Most parts of the products were hydrolyzed to monosaccharides by commercial cellulase, alpha-amylase, glucoamylase, and a mixture of these enzymes. However, some oligosaccharides were not hydrolyzed completely by them. Methylation analysis showed that the oligosaccharides contained greatly branched sugars including 2,3,4,6-linked hexose residues and so forth, some of which could not be hydrolyzed by the enzymes.