Method for producing modified xylopolysaccharide

A method for producing a modified xylopolysaccharide,

• the method comprising the steps of:
• providing biomass as a raw material which comprises xylan in plant cell walls thereof, wherein the xylan comprises at least one of substituents selected from the group consisting of an acetyl group, a feruloylarabinofuranosyl group and a coumaroylarabinofuranosyl group on a side chain thereof;
• preparing a slurry which contains the biomass in 10 mass % to 30 mass % as a solid content;
• feeding the slurry into a cylindrical plug-flow reactor which comprises a passage controlling mechanism inside the reactor, wherein
• the passage controlling mechanism generates a plug flow which is an extruded flow and makes the slurry flow with a distribution of equal velocities inside the reactor,
• the passage controlling mechanism comprising
• a columnar rotator that is rotatable around a center axis arranged in a direction parallel to a flow of the slurry, and
• a plurality of passage controlling blades including a plate member which is arranged on a side surface of the rotator, directed outward the rotator and extended in a direction of the flow of the slurry;
• and
• performing a continuous hydrothermal treatment to the slurry in the reactor to produce the modified xylopolysaccharide in which the substituent on the side chain of the xylan is preserved, wherein
• the modified xylopolysaccharide has a theoretical yield of more than 60 percent, and
• the continuous hydrothermal treatment is performed under controlled conditions:
• at a temperature of 160° C. or more, at a pressure equal to or higher than a saturated water vapor pressure at said temperature, and with a severity parameter R0 ranging from 3000 to 7000 calculated by the following equation (1),
• R
• o
• =
• ∫
• 0
• t
• ⁢
• exp
• ⁡
• (
• T
• ⁡
• (
• t
• )
• -
• T
• r
• ω
• )
• ⁢
• dt
• wherein T(t) is a time variation of a temperature (° C.), Tr is a standard temperature (100° C.), t is a time (min) and ω is a constant (=14.75).