Effect of ammonia treatment on enzymatic hydrolysis and cell wall components of Erianthus

Abstract

Powdered samples of Erianthus were treated with anhydrous ammonia at 50–140 °C. The crystal structure of cellulose in the sample changed to cellulose IIII, and its crystallite size increased with increasing temperature. Lignin content decreased with increasing temperature, while most reducing sugars, including glucose, were maintained at nearly 80%. Enzymatic hydrolysis of the ammonia-treated samples was carried out at 37 °C using a mixture of cellulase and β-glucosidase in solution. The samples treated at a higher temperature showed better enzymatic degradability. Furthermore, transverse sections of Erianthus stem were also treated with ammonia, and cell wall components and their distributions were detected with microscopic observation. By using fluorescence microscopy, it was also found that lignin content decreased with increased temperature. The immuno-labeling of pectin and β-1,3-1,4-glucan showed a change to a water-soluble form and complete removal by the ammonia treatment. However, xylan had substantial resistance to ammonia treatment.