Rate-constraining changes in surface properties, porosity and hydrolysis kinetics of lignocellulose in the course of enzymatic saccharification
| Autor: | Simo Laakso, Ville Pihlajaniemi, Mika Henrikki Sipponen, Anne Kallioinen, Antti Nyyssölä |
|---|---|
| Přispěvatelé: | Department of Biotechnology and Chemical Technology, Department of Bioproducts and Biosystems, Aalto-yliopisto, Aalto University |
| Rok vydání: | 2015 |
| Předmět: |
0106 biological sciences
0301 basic medicine Kinetics Cellulase Management Monitoring Policy and Law 01 natural sciences Applied Microbiology and Biotechnology 03 medical and health sciences chemistry.chemical_compound Hydrolysis Cellulose surface Kinetic modelling Bioenergy 010608 biotechnology Lignin Cellulases Cellulose Inhibition biology Lignin surface Renewable Energy Sustainability and the Environment business.industry Research food and beverages Straw Pore size distribution Biotechnology 030104 developmental biology General Energy chemistry Chemical engineering Product inhibition biology.protein Enzymatic lignocellulose hydrolysis business |
| Zdroj: | Biotechnology for Biofuels |
| ISSN: | 1754-6834 |
| Popis: | Background Explaining the reduction of hydrolysis rate during lignocellulose hydrolysis is a challenge for the understanding and modelling of the process. This article reports the changes of cellulose and lignin surface areas, porosity and the residual cellulase activity during the hydrolysis of autohydrolysed wheat straw and delignified wheat straw. The potential rate-constraining mechanisms are assessed with a simplified kinetic model and compared to the observed effects, residual cellulase activity and product inhibition. Results The reaction rate depended exclusively on the degree of hydrolysis, while enzyme denaturation or time-dependent changes in substrate hydrolysability were absent. Cellulose surface area decreased linearly with hydrolysis, in correlation with total cellulose content. Lignin surface area was initially decreased by the dissolution of phenolics and then remained unchanged. The dissolved phenolics did not contribute to product inhibition. The porosity of delignified straw was decreased during hydrolysis, but no difference in porosity was detected during the hydrolysis of autohydrolysed straw. Conclusions Although a hydrolysis-dependent increase of non-productive binding capacity of lignin was not apparent, the dependence of hydrolysis maxima on the enzyme dosage was best explained by partial irreversible product inhibition. Cellulose surface area correlated with the total cellulose content, which is thus an appropriate approximation of the substrate concentration for kinetic modelling. Kinetic models of cellulose hydrolysis should be simplified enough to include reversible and irreversible product inhibition and reduction of hydrolysability, as well as their possible non-linear relations to hydrolysis degree, without overparameterization of particular factors. Electronic supplementary material The online version of this article (doi:10.1186/s13068-016-0431-3) contains supplementary material, which is available to authorised users. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink