Process for production of pure glucose from cellulose

A process for production of glucose having purity of greater than 98% from pre-treated cellulosic biomass comprising the steps of:

• a) subjecting a pre-treated cellulosic biomass comprising 60% to 90% cellulose to a two-step acid-acid treatment method to obtain a treated cellulosic biomass residue comprising 98-99% cellulose, wherein said acid-acid treatment comprises;
• (i) contacting pre-treated cellulosic biomass with acid having concentration in the range of 1% (w/w) to 3% (w/w) at a temperature in the range of 100° C. to 130° C. for period of 5 minutes to 20 minutes to obtain a first cellulosic biomass comprising cellulose having concentration in the range of 80-95%;
• and
• (ii) contacting said first cellulosic biomass with acid having concentration in the range of 1% (w/w) to 3% (w/w) at a temperature in the range of 100° C. to 130° C. for period of 5 minutes to 20 minutes to obtain a first cellulosic biomass comprising cellulose having concentration in the range of 98-99%;
• b) contacting said treated cellulosic biomass residue with cellulose at a concentration in the range of 40 mg/g to 50 mg/g of treated cellulosic biomass residue at a temperature in the range of 40° C. to 50° C. for period of 90 minutes to 120 minutes to obtain cellulose hydrolysate, and insoluble components, wherein said cellulose hydrolysate comprises sugars containing 90 to 98% of monomeric glucose;
• c) separating the cellulose hydrolysate from cellulose and insoluble components;
• d) subjecting the cellulose hydrolysate obtained from step (c) to a filtration process to obtain a permeate fraction comprising sugars, wherein said sugars comprise more than 99% glucose and a retentate fraction comprising oligomers, cellobiose, cello-triose or combinations thereof;
• e) treating the retentate fraction with β-glucosidase to obtain a sugar solution wherein the said sugar comprises greater than 99% glucose purity, and separating the sugar solution from β-glucosidase;
• and
• f) mixing the permeate fraction and the sugar solution to obtain greater than 98% glucose purity.

A process for production of glucose having purity of greater than 98% from pre-treated cellulosic biomass comprising the steps of:

• a) subjecting pre-treated cellulosic biomass comprising 60% to 90% cellulose to a three-step acid-alkali-acid treatment method to obtain a treated cellulosic biomass residue comprising 98% to 99% cellulose, wherein said acid-alkali-acid treatment comprises:
• (i) contacting pre-treated cellulosic biomass with acid having concentration of 1% (w/w) to 3%% (w/w) at a temperature in the range of 100° C. to 130° C. for period of 5 minutes to 1 minutes to obtain a first cellulosic biomass comprising cellulose having concentration in the range of 80% to 95%;
• (ii) contacting said first cellulosic biomass with alkali having concentration in the range of 0.1% to −0.5% (w/w) at a temperature in the range of 100° C. to 130° C. for period of 5 minutes to 30 minutes to obtain a second cellulosic biomass comprising cellulose having concentration in the range of 95% to 98%;
• and
• (iii) contacting said second cellulosic biomass with acid having concentration in the range of 1% to 3% (w/w) at a temperature in the range of 100° C. to 130° C. for period of 5 minutes to 30 minutes to obtain a treated cellulosic biomass residue comprising cellulose having concentration in the range of 98% to 99%,
• b) contacting said treated cellulosic biomass residue with cellulase having concentration in the range of 40 mg/g to 50 mg/g of cellulosic biomass residue at a temperature in the range of 40° C. to 50° C. for period of 90 minute to 120 minutes to obtain a cellulose hydrolysate, and insoluble components, wherein said cellulose hydrolysate comprises sugars containing 90-98% of monomeric glucose;
• c) separating the cellulose hydrolysate from cellulase and insoluble components;
• d) subjecting the cellulose hydrolysate to a filtration process to obtain a permeate fraction comprising sugars, wherein said sugars comprise greater than 99% glucose and a retentate fraction comprising oligomers, cellobiose, cellotriose, or combinations thereof;
• e) treating the retentate fraction with β-glucosidase to obtain a sugar solution, wherein said sugar comprises greater than 99% glucose, and separating the sugar solution from β-glucosidase;
• and
• f) mixing the permeate fraction and the sugar solution and evaporating the sugar solution to obtain greater than 98% glucose.