Study On Methane Production Performance Of Saccharide Substances During Anaerobic Digestion

As the most abundant organic substance in nature,saccharides are widely found in many kinds of wastes.This project mainly studies on the methane production performance of saccharides during the anaerobic digestion(AD),the co-digestion of the main components of lignocellulose(cellulose,hemicellulose and lignin),and methane production performance of textile wastes with high cellulose content in AD.The main research contents and conclusions are as follows:Firstly,the methane production performance of 20 kinds of saccharides during AD were studied,including monosaccharides,oligosaccharides and polysaccharides.The results showed that the methane production potential of saccharides were high,most of them were above 300 mL/g,and their biodegradation rates were above 64%.The type of glycosidic bond had a certain effect on the methane production of disaccharides in AD.The methane production of oligosaccharides and polysaccharides were slightly higher than their monosaccharide units.The methane production of monosaccharides and oligosaccharides did not show lag phase,but the anaerobic digestion of most polysaccharides had a lag phase around 2-3 days.Subsequently,cellulose,hemicellulose and lignin were extracted from wheat straw,and their properties and structures were tested and analyzed.the.The anaerobic co-digestion was then carried out by mixing the three substances in pairs at a ratio of 1:0,3:1,1:1,1:3 and 0:1 respectively.The results showed that the co-digestion of cellulose and hemicellulose could increase the methane production,and methane production was highest when the cellulose to hemicellulose ratio was 3:1.When cellulose and lignin or hemicellulose and lignin were co-digested,the methane production decreased with the increasing of lignin content.The results of microbial community structure analysis showed that the increase of methane production during the co-digestion of cellulose and hemicellulose may be related to Clostridium sensu stricto,Petrimonas,Sedimentibacter and Methanospirillum,and Methanogenspirillum was found to be important for the methane production of hemicellulose during AD.The anaerobic digestion experiment was also carried out for 11 kinds of textiles as substrates,and the results showed that they all had high methane production potential,except the blue denim and abaca cloth,methane production of most textiles were around 330 mL/g VS,the biodegradation rates were above 50%(except the blue denim).The morphological changes of textiles during anaerobic digestion and SEM images showed that the degradation rates of fibers were different,and the thickness of fibers had an important influence on the degradation rate and degree.The dyes attached to the fibers may influence the degradation and methane production.This research offered basic information for AD performance of saccharide substrates,methane production from co-digestion of cellulose,hemicellulose,and lignin,and digestablities of textile wastes,which could provide reference for the future utilization of organic wastes containing saccharides.