fA cellular automaton model of crystalline cellulose hydrolysis by cellulases
<p>Abstract</p> <p>Background</p> <p>Cellulose from plant biomass is an abundant, renewable material which could be a major feedstock for low emissions transport fuels such as cellulosic ethanol. Cellulase enzymes that break down cellulose into fermentable sugars are co...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2011-10-01
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| Series: | Biotechnology for Biofuels |
| Online Access: | http://www.biotechnologyforbiofuels.com/content/4/1/39 |
| _version_ | 1818230370321039360 |
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| author | Little Bryce A Warden Andrew C Haritos Victoria S |
| author_facet | Little Bryce A Warden Andrew C Haritos Victoria S |
| author_sort | Little Bryce A |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Cellulose from plant biomass is an abundant, renewable material which could be a major feedstock for low emissions transport fuels such as cellulosic ethanol. Cellulase enzymes that break down cellulose into fermentable sugars are composed of different types - cellobiohydrolases I and II, endoglucanase and β-glucosidase - with separate functions. They form a complex interacting network between themselves, soluble hydrolysis product molecules, solution and solid phase substrates and inhibitors. There have been many models proposed for enzymatic saccharification however none have yet employed a cellular automaton approach, which allows important phenomena, such as enzyme crowding on the surface of solid substrates, denaturation and substrate inhibition, to be considered in the model.</p> <p>Results</p> <p>The Cellulase 4D model was developed <it>de novo </it>taking into account the size and composition of the substrate and surface-acting enzymes were ascribed behaviors based on their movements, catalytic activities and rates, affinity for, and potential for crowding of, the cellulose surface, substrates and inhibitors, and denaturation rates. A basic case modeled on literature-derived parameters obtained from <it>Trichoderma reesei </it>cellulases resulted in cellulose hydrolysis curves that closely matched curves obtained from published experimental data. Scenarios were tested in the model, which included variation of enzyme loadings, adsorption strengths of surface acting enzymes and reaction periods, and the effect on saccharide production over time was assessed. The model simulations indicated an optimal enzyme loading of between 0.5 and 2 of the base case concentrations where a balance was obtained between enzyme crowding on the cellulose crystal, and that the affinities of enzymes for the cellulose surface had a large effect on cellulose hydrolysis. In addition, improvements to the cellobiohydrolase I activity period substantially improved overall glucose production.</p> <p>Conclusions</p> <p>Cellulase 4D simulates the enzymatic hydrolysis of cellulose to glucose by surface and solution phase-acting enzymes and accounts for complex phenomena that have previously not been included in cellulose hydrolysis models. The model is intended as a tool for industry, researchers and educators alike to explore options for enzyme engineering and process development and to test hypotheses regarding cellulase mechanisms.</p> |
| first_indexed | 2024-12-12T10:33:25Z |
| format | Article |
| id | doaj.art-22fd8ea3b0e247ec8acb925d662bb7c7 |
| institution | Directory Open Access Journal |
| issn | 1754-6834 |
| language | English |
| last_indexed | 2024-12-12T10:33:25Z |
| publishDate | 2011-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Biotechnology for Biofuels |
| spelling | doaj.art-22fd8ea3b0e247ec8acb925d662bb7c72022-12-22T00:27:17ZengBMCBiotechnology for Biofuels1754-68342011-10-01413910.1186/1754-6834-4-39fA cellular automaton model of crystalline cellulose hydrolysis by cellulasesLittle Bryce AWarden Andrew CHaritos Victoria S<p>Abstract</p> <p>Background</p> <p>Cellulose from plant biomass is an abundant, renewable material which could be a major feedstock for low emissions transport fuels such as cellulosic ethanol. Cellulase enzymes that break down cellulose into fermentable sugars are composed of different types - cellobiohydrolases I and II, endoglucanase and β-glucosidase - with separate functions. They form a complex interacting network between themselves, soluble hydrolysis product molecules, solution and solid phase substrates and inhibitors. There have been many models proposed for enzymatic saccharification however none have yet employed a cellular automaton approach, which allows important phenomena, such as enzyme crowding on the surface of solid substrates, denaturation and substrate inhibition, to be considered in the model.</p> <p>Results</p> <p>The Cellulase 4D model was developed <it>de novo </it>taking into account the size and composition of the substrate and surface-acting enzymes were ascribed behaviors based on their movements, catalytic activities and rates, affinity for, and potential for crowding of, the cellulose surface, substrates and inhibitors, and denaturation rates. A basic case modeled on literature-derived parameters obtained from <it>Trichoderma reesei </it>cellulases resulted in cellulose hydrolysis curves that closely matched curves obtained from published experimental data. Scenarios were tested in the model, which included variation of enzyme loadings, adsorption strengths of surface acting enzymes and reaction periods, and the effect on saccharide production over time was assessed. The model simulations indicated an optimal enzyme loading of between 0.5 and 2 of the base case concentrations where a balance was obtained between enzyme crowding on the cellulose crystal, and that the affinities of enzymes for the cellulose surface had a large effect on cellulose hydrolysis. In addition, improvements to the cellobiohydrolase I activity period substantially improved overall glucose production.</p> <p>Conclusions</p> <p>Cellulase 4D simulates the enzymatic hydrolysis of cellulose to glucose by surface and solution phase-acting enzymes and accounts for complex phenomena that have previously not been included in cellulose hydrolysis models. The model is intended as a tool for industry, researchers and educators alike to explore options for enzyme engineering and process development and to test hypotheses regarding cellulase mechanisms.</p>http://www.biotechnologyforbiofuels.com/content/4/1/39 |
| spellingShingle | Little Bryce A Warden Andrew C Haritos Victoria S fA cellular automaton model of crystalline cellulose hydrolysis by cellulases Biotechnology for Biofuels |
| title | fA cellular automaton model of crystalline cellulose hydrolysis by cellulases |
| title_full | fA cellular automaton model of crystalline cellulose hydrolysis by cellulases |
| title_fullStr | fA cellular automaton model of crystalline cellulose hydrolysis by cellulases |
| title_full_unstemmed | fA cellular automaton model of crystalline cellulose hydrolysis by cellulases |
| title_short | fA cellular automaton model of crystalline cellulose hydrolysis by cellulases |
| title_sort | fa cellular automaton model of crystalline cellulose hydrolysis by cellulases |
| url | http://www.biotechnologyforbiofuels.com/content/4/1/39 |
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