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Pore-scale dynamics of enzyme adsorption, swelling and reactive dissolution determine sugar yield in hemicellulose hydrolysis for biofuel production.

ABSTRACT: Hemicelluloses are the earth's second most abundant structural polymers, found in lignocellulosic biomass. Efficient enzymatic depolymerization of xylans by cleaving their ?-(1???4)-glycosidic bonds to produce soluble sugars is instrumental to the cost-effective production of liquid biofuels. Here we show that the multi-scale two-phase process of enzymatic hydrolysis of amorphous hemicelluloses is dominated by its smallest scale-the pores. In the crucial first five hours, two to fourfold swelling of the xylan particles allow the enzymes to enter the pores and undergo rapid non-equilibrium adsorption on the pore surface before they hydrolyze the solid polymers, albeit non-competitively inhibited by the products xylose and xylobiose. Rapid pore-scale reactive dissolution increases the solid carbohydrate's porosity to 80-90%. This tightly coupled experimental and theoretical study quantifies the complex temporal dynamics of the transport and reaction processes coupled across scales and phases to show that this unique pore-scale phenomenon can be exploited to accelerate the depolymerization of hemicelluloses to monomeric sugars in the first 5-6?h. We find that an 'optimal substrate loading' of 5?mg/ml (above which substrate inhibition sets in) accelerates non-equilibrium enzyme adsorption and solid hemicellulose depolymerization at the pore-scale, which contributes three-quarters of the soluble sugars produced for bio-alcohol fermentation.

SUBMITTER: Dutta SK

PROVIDER: S-EPMC5131285 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Pore-scale dynamics of enzyme adsorption, swelling and reactive dissolution determine sugar yield in hemicellulose hydrolysis for biofuel production.

Dutta Sajal Kanti SK Chakraborty Saikat S

Scientific reports 20161201

Hemicelluloses are the earth's second most abundant structural polymers, found in lignocellulosic biomass. Efficient enzymatic depolymerization of xylans by cleaving their β-(1 → 4)-glycosidic bonds to produce soluble sugars is instrumental to the cost-effective production of liquid biofuels. Here we show that the multi-scale two-phase process of enzymatic hydrolysis of amorphous hemicelluloses is dominated by its smallest scale-the pores. In the crucial first five hours, two to fourfold swellin ...[more]

PMID: 27905534

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Dataset Information

Pore-scale dynamics of enzyme adsorption, swelling and reactive dissolution determine sugar yield in hemicellulose hydrolysis for biofuel production.

Publications

Pore-scale dynamics of enzyme adsorption, swelling and reactive dissolution determine sugar yield in hemicellulose hydrolysis for biofuel production.

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