A process for treating rice bran, preferably defatted rice bran, to produce a high value protein product and a cellulosic residue both from rice bran. The high value protein product is useful as a protein supplement or feed for livestock and poultry and the cellulosic residue has value as a feedstock for a thermochemical process unit for the production of a biofuel. The rice bran is subjected protein hydrolysis and a resulting liquid stream containing hydrolyzed proteins is sent through a two membrane filtration stages, the first being a microfiltration and the second being a nanofiltration stage.
