A Database of Sugar Composition of Agricultural Wastes for Their Efficient Reuse and D-xylose Extraction Methods from Agricultural Wastes
Changho Cho*, Masahiro Hatsu* and Kazuhiro Takamizawa*Abstract
Lignocellulose is abundant in various agricultural wastes. Lignocellulosics can be hydrolyzed to liberate sugars, with emphasis on large-scale production of useful compounds by means of acid or enzymatic hydrolysis. Many agro-industrial wastes contain hemicellulose in relatively high amounts. In nature, hemicellulose is the second most abundant constituent of lignocelluloses. Bioconversion of hemicellulose produces monosaccharides i.e. D-xylose. This xylose thus could be used as a substrate for fermentation to various useful compounds such as butanol and xylitol. The purpose of the present study is the preparation of a database of sugar composition of agricultural wastes and to develop a method for the production of D-xylose for effective utilization of agricultural wastes.
For the hard shell of bean group, it was found by acid hydrolysis that the content of D-xylose was higher than the residue of soft-drink products. 36g, 18.7g, 18.3g, 17.1g, 12.6g of D-xylose were contained in 100g of pistachio shells, walnut shells, sunflower seed peels, barley brans and chestnut shells, respectively and it was found to be very good renewable source of D-xylose. In the case of the enzymatic hydrolysis of raw pistachio shells which were only subjected to milling pretreatment (0.5 mm size), 36g of D-xylose was produced when mixed enzyme solution from Penicillium sp. AHT-1 and Rhizomucor pusillus containing 3,000 and 33 U per g of sample with xylanase and beta-xylosidase activity, respectively. The rate of the enzymatic hydrolysis in this finding was about 100%, compared to acid hydrolysis.
Key words: agricultural wastes, database, D-xylose, acid hydrolysis, enzymatic hydrolysis