acts to break glycoside between these sugars in the polymer chain and releases xylose glucose mannose and arabinose sugars respectively this action results in a concentrated aqueous solution at approximately the same solids concentration as the feed to this hydrolysis step mixture of these sugars appropriate for sale to a third party since hemicellulose composition varies with the raw material and with conditions employed in steps 1 and 2 the proportion of enzyme used for this hydrolysis step will vary and must be adjusted with each situation the conditions fall in the following ranges a standard condition of 120 u00b0 c at ph 4 5 for one hour converts all hemicellulose in these liquid streams into a mixture of 5 and 6 carbon sugars at about 99 yield the ratio of pentose to hexose sugars depends on the type of biomass feed stock for arundo donax the ratio amounts to about 9 5 3 2 of xylose glucose galactose mannose xylose is a 5 carbon sugar while the others are 6 carbon sugars rates of fermentation and hydrogenation and the final yield of either ethanol or of glycol blends are directly affected by the concentration of the mixed sugar feed typically the results are maximized and the operating costs minimized at 20 to 25 sugar solids in the feed to those processes recovery and concentration of simple 5 and 6 carbon sugars from the foregoing steps involves two sequential operations first the sugars are separated from the lignin contained in the product of the foregoing step producing a highly purified sugar.