Advancing continuous enzymatic hydrolysis for improved biomass saccharification

Abstract Background A deployable, continuous enzymatic hydrolysis (CEH) process can address cost and commercialization risks associated with second-generation (Gen2) biorefinery sugar/lignin/ethanol production while contributing to energy supply and security. Developments in commercial enzymatic hyd...

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Main Authors: Roman Brunecky, Yudong Li, Stephen R. Decker, Michael E. Himmel
Format: Article
Language:English
Published: BMC 2025-07-01
Series:Biotechnology for Biofuels and Bioproducts
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Online Access:https://doi.org/10.1186/s13068-025-02680-z
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author Roman Brunecky
Yudong Li
Stephen R. Decker
Michael E. Himmel
author_facet Roman Brunecky
Yudong Li
Stephen R. Decker
Michael E. Himmel
author_sort Roman Brunecky
collection DOAJ
description Abstract Background A deployable, continuous enzymatic hydrolysis (CEH) process can address cost and commercialization risks associated with second-generation (Gen2) biorefinery sugar/lignin/ethanol production while contributing to energy supply and security. Developments in commercial enzymatic hydrolysis formulations targeting Gen2 pretreated biomass such as deacetylated mechanically refined (DMR) biomass necessitate a reassessment of the existing hybrid simultaneous saccharification and fermentation (SSF) approach. Notably, the practice of "finishing hydrolysis" in SSF has become problematic with the introduction of oxidative enzymes, such as lytic polysaccharide monooxygenases (LPMOs), into commercial cellulase formulations as these require specific redox conditions and cofactor. Moreover, continuous SSF has not been demonstrated at commercial scale, limiting deployment and the associated economic benefits to farmers, producers, and support industries. Results Continuous enzymatic hydrolysis (CEH) was demonstrated at bench scale to enable optimal saccharification performance of deacetylated mechanically refined (DMR) pretreated biomass. Diafiltration was demonstrated to retain pretreated biomass solids and enzymes for continuous reaction while removing solubilized product sugars in situ. A significant breakthrough afforded by the CEH process is its ability to achieve equivalent endpoint conversions with approximately 50% lower enzyme loading. Yields of glucose and xylose were increased ~ 15% and ~ 4%, respectively, over batch hydrolysis. Unlike SSF using yeast or Zymomonas, CEH allows precise optimization of pH, temperature, oxygen tension, LPMO mediator concentration, and removal of end-product inhibitors. Conclusions Advanced CEH holds promise as a transformational, process-intensified, and cost-effective method for producing soluble clarified biomass sugars and insoluble lignin-rich streams. Enhancing saccharification performance, optimizing operating parameters, and employing membrane filtration will help overcome existing challenges and enable the efficient production of valuable biomaterials from lignocellulosic biomass.
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spelling doaj-art-902db3e6e5314ab185ff9dad1b3c821e2025-08-20T03:46:07ZengBMCBiotechnology for Biofuels and Bioproducts2731-36542025-07-0118111110.1186/s13068-025-02680-zAdvancing continuous enzymatic hydrolysis for improved biomass saccharificationRoman Brunecky0Yudong Li1Stephen R. Decker2Michael E. Himmel3Biosciences Center, National Renewable Energy LaboratoryCatalytic Carbon Transformation and Scale-Up Center, National Renewable Energy LaboratoryBiosciences Center, National Renewable Energy LaboratoryBiosciences Center, National Renewable Energy LaboratoryAbstract Background A deployable, continuous enzymatic hydrolysis (CEH) process can address cost and commercialization risks associated with second-generation (Gen2) biorefinery sugar/lignin/ethanol production while contributing to energy supply and security. Developments in commercial enzymatic hydrolysis formulations targeting Gen2 pretreated biomass such as deacetylated mechanically refined (DMR) biomass necessitate a reassessment of the existing hybrid simultaneous saccharification and fermentation (SSF) approach. Notably, the practice of "finishing hydrolysis" in SSF has become problematic with the introduction of oxidative enzymes, such as lytic polysaccharide monooxygenases (LPMOs), into commercial cellulase formulations as these require specific redox conditions and cofactor. Moreover, continuous SSF has not been demonstrated at commercial scale, limiting deployment and the associated economic benefits to farmers, producers, and support industries. Results Continuous enzymatic hydrolysis (CEH) was demonstrated at bench scale to enable optimal saccharification performance of deacetylated mechanically refined (DMR) pretreated biomass. Diafiltration was demonstrated to retain pretreated biomass solids and enzymes for continuous reaction while removing solubilized product sugars in situ. A significant breakthrough afforded by the CEH process is its ability to achieve equivalent endpoint conversions with approximately 50% lower enzyme loading. Yields of glucose and xylose were increased ~ 15% and ~ 4%, respectively, over batch hydrolysis. Unlike SSF using yeast or Zymomonas, CEH allows precise optimization of pH, temperature, oxygen tension, LPMO mediator concentration, and removal of end-product inhibitors. Conclusions Advanced CEH holds promise as a transformational, process-intensified, and cost-effective method for producing soluble clarified biomass sugars and insoluble lignin-rich streams. Enhancing saccharification performance, optimizing operating parameters, and employing membrane filtration will help overcome existing challenges and enable the efficient production of valuable biomaterials from lignocellulosic biomass.https://doi.org/10.1186/s13068-025-02680-zBiomassCellulaseEnzyme hydrolysisSaccharificationBiomass sugarsLignocellulose
spellingShingle Roman Brunecky
Yudong Li
Stephen R. Decker
Michael E. Himmel
Advancing continuous enzymatic hydrolysis for improved biomass saccharification
Biotechnology for Biofuels and Bioproducts
Biomass
Cellulase
Enzyme hydrolysis
Saccharification
Biomass sugars
Lignocellulose
title Advancing continuous enzymatic hydrolysis for improved biomass saccharification
title_full Advancing continuous enzymatic hydrolysis for improved biomass saccharification
title_fullStr Advancing continuous enzymatic hydrolysis for improved biomass saccharification
title_full_unstemmed Advancing continuous enzymatic hydrolysis for improved biomass saccharification
title_short Advancing continuous enzymatic hydrolysis for improved biomass saccharification
title_sort advancing continuous enzymatic hydrolysis for improved biomass saccharification
topic Biomass
Cellulase
Enzyme hydrolysis
Saccharification
Biomass sugars
Lignocellulose
url https://doi.org/10.1186/s13068-025-02680-z
work_keys_str_mv AT romanbrunecky advancingcontinuousenzymatichydrolysisforimprovedbiomasssaccharification
AT yudongli advancingcontinuousenzymatichydrolysisforimprovedbiomasssaccharification
AT stephenrdecker advancingcontinuousenzymatichydrolysisforimprovedbiomasssaccharification
AT michaelehimmel advancingcontinuousenzymatichydrolysisforimprovedbiomasssaccharification