The present disclosure provides a process for production of glucose having purity greater than 98% from pretreated cellulosic biomass comprising 50-95% cellulose, using thermo-chemical and enzymatic treatments. The process of the disclosure involves mild acid and/or alkali treatment of the pretreated cellulosic biomass for production of treated cellulosic biomass residue comprising polysaccharides containing greater than 98% glucose. The treatment results in high purity cellulose that is highly amenable to enzymatic hydrolysis and yields glucose having purity greater than 98%. The process of the disclosure also involves membrane separation of enzymes and oligosaccharides for recycling and separation of glucose to avoid product feedback inhibition.
