Enhanced saccharification of reed and rice straws by the addition of β -1,3-1,4-glucanase with broad substrate specificity and calcium ion

The possibility of using additive enzymes to improve the saccharification of lignocellulosic substrates with commercial cellulolytic enzymes was studied. Reed ( Phragmites communis ) and rice ( Oryza sativa ) straw powders were pretreated with NaOH/steam via a high-temperature explosion system. The saccharification of untreated reed and rice straw powders by commercial enzymes (Celluclast 1.5 L + Novozym 188) was not significantly increased by the addition of xylanases (Xyn10J, XynX), a cellulase (Cel6H), and a β -1,3-1,4-glucanase (BGlc8H) with broad substrate specificity. The saccharification of the pretreated reed and rice straw powders by the commercial enzymes was increased by 10.4 and 4.8 %, respectively, by the addition of BGlc8H. In the presence of Ca 2+ and BGlc8H, the saccharification of the pretreated reed and rice straw powders by the commercial enzymes was increased by 18.5 and 11.7 %, respectively. No such effect of Ca 2+ was observed with Xyn10J, XynX, or Cel6H. The results suggest that the enzymatic conversion of lignocellulosic biomass to reducing sugars could be enhanced by certain additive enzymes such as β -1,3-1,4-glucanase, and that the enhancement could further be increased by Ca 2+ .