If the biomass is 100 gram, where the glucan and xylan presented in the biomass are 40 and 20 gram, respectively, the maximum theoretical yield of total glucose and xylose will be 40/0.9 and 20/0.88 gram.

First, you should check the chemical composition of biomass as polysaccharides content, and individual cellusoe, glucomannan, xylan content. Second polymeric cellulose, glucomannan and xylan will be hydrolyzed as monomer. During hydrolysis anhydrous form will be changed to monosaccharide, which increased the weight. That is the reason for 0.9 in cellulose or glucomannan (hexose) and 0.88 in xylose or arabinose (pentose)

How can i calculate mole of cellulose or glucose in biomass

 Liheng Chen do you have a paper,where they have calculated the maximum theoretical yield of total glucose?