NOVELTY - Preparation of cellulose microfibrils from herbaceous plant material involves contacting the herbaceous plant biomass with an enzyme composition comprising endo-glucanase(s) and polysaccharide hydrolases to form an enzyme-treated biomass and mechanically processing the enzyme-treated biomass. The polysaccharide hydrolases are chosen from endo-polygalacturonase, arabinofuranosidase pectin lyase, pectate lyase, pectin methyl esterase, endo-arabinanase, endo-galactanase, galactosidase, rhamnogalacturonan hydrolase, rhamnogalacturonan lyase and/or xylanase.    USE - Preparation of cellulose microfibrils from herbaceous plant material used in microfibrillated cellulose material used as viscosity improver, strengthening agent in concrete, cementitious composition, composite material, coating composition for reinforcement, emulsion, paper (all claimed), cardboards and films.    ADVANTAGE - The method provides excellent microfibrillation to the material. The cellulose microfibrils have excellent mechanical strength.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) microfibrillated cellulose material, which comprises cellulose microfibrils and matrix polysaccharides chosen from homogalacturonan, (1-4)-( beta )-D-(galacto)mannan, (1-4)-( beta )-D-(galacto)(gluco)mannan, (1-4)-( beta )-D-(gluco)mannan, (1-4)-( beta )-D-galactan, xyloglucan, (1-4)-( beta )-D-xylan and/or (1-4)-( beta )-D-arabinoxylan;    (2) composition, which comprises microfibrillated cellulose material;    (3) composite material, which comprises a resin and 95 wt.% or less microfibrillated cellulose material;    (4) cementitious composition, which comprises binder and less than 10 wt.% microfibrillated cellulose material;    (5) concrete composition, which comprises binder, aggregate material and less than 10 wt.% microfibrillated cellulose material;    (6) coating composition, which comprises binder and less than 10 wt.% microfibrillated cellulose material;    (7) emulsion, which comprises aqueous phase, oil phase, and less than 10 wt.% microfibrillated cellulose material; and    (8) paper, which comprises less than 40 wt.% microfibrillated cellulose material.