Methods and systems for enzymatic hydrolysis of pretreated biomass at high solids concentrations

Abstract

A method of enzymatically hydrolyzing pretreated lignocellulosic biomass at high solids concentration includes introducing pretreated biomass to a hydrolysis reactor, to hydrolyze the cellulose to glucose monomer and glucose oligomers, and circulating a liquid stream, from which glucose is removed to reduce glucose inhibition of cellulose hydrolysis. A surfactant may be added to the hydrolysis reactor. Heat and / or acid treatment of the glucose oligomers may be used to generate additional glucose monomer. Some variations introduce pretreated biomass to a hydrolysis reactor to hydrolyze cellulose to glucose monomer and glucose oligomers, followed by conveying a portion of the solid phase to a mechanical refiner and / or a unit under reduced pressure, to generate a refined and / or exploded solid phase; and recycling the refined and / or exploded solid phase, optionally reheated, back to an input of the hydrolysis reactor.

Description

PRIORITY DATA[0001]This non-provisional patent application is a continuation of U.S. patent application Ser. No. 15 / 276,834, filed on Sep. 27, 2016, which claims priority to U.S. Provisional Patent App. No. 62 / 234,415, filed on Sep. 29, 2016, each of which is incorporated by reference herein.FIELD OF THE INVENTION[0002]The present invention generally relates to methods and systems for preparing fermentable sugars from lignocellulosic biomass.BACKGROUND OF THE INVENTION[0003]Enzymatic hydrolysis is a key process for a biorefinery based on production of sugars. The rate of enzymatic hydrolysis, final carbohydrate conversion, and concentration all critically affect the technoeconomic feasibility of commercial operations. Enzymatic hydrolysis performed at high solids loading offers several advantages over low solids loading, because of higher sugar and bioproduct concentrations, smaller equipment, less energy for heating and cooling of the slurry, and lower hydraulic loads. Therefore, e...

AI Technical Summary

Benefits of technology

[0014](c) circulating a liquid stream in a circulation line configured from an output of the reactor back to an input of the hydrolysis reactor, wherein at least a portion of the glucose is removed from the circulation line to reduce glucose inhibition of cellulose hydrolysis.

[0017]Optionally, at least a portion of the glucose oligomers may be removed from the circulation line to reduce glucose oligomer inhibition of cellulose hydrolysis. The removal of glucose oligomers may target cellobiose, which is a relatively high enzyme inhibition effect, compared to larger oligomers.

Problems solved by technology

However, hydrolysis at high insoluble solids introduces a lack of available water in the reactor.

Therefore, high-solids hydrolysis can create rheological challenges, cause insufficient mixing, reduce mass- and heat-transfer efficiency, and increase the concentration of enzymes inhibitors in the system, resulting in low conversion of carbohydrates into fermentable sugars.

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