Hydrolysis of Steam-Pretreated Lignocellulose: synergism and adsorption for cellobiohydrolase I and endoglucanase II of Trichoderma reesei.
(1999) In Applied Biochemistry and Biotechnology 82(3). p.243-258- Abstract
- The mechanism of hydrolysis of cellulose is important for improving the enzymatic conversion in bioprocesses based on lignocellulose. Adsorption and hydrolysis experiments were performed with cellobiohydrolase I (CBH I) and endoglucanase II (EG II) from Trichoderma reesei on a realistic lignocellulose substrates: steam-pretreated willow. The enzymes were studied both alone and in equimolar mixtures. Adsorption isotherms were determined at 4 and 40°C during 90-min reaction times. Both CBH I and EG II adsorbed stronger at 40 than at 4°C. The time course of adsorption and hydrolysis, 3 min to 48 h, was studied at 40°C. About 90% of the cellulases were adsorbed within 2 h. The hydrolysis rate was high in the beginning but decreased during the... (More)
- The mechanism of hydrolysis of cellulose is important for improving the enzymatic conversion in bioprocesses based on lignocellulose. Adsorption and hydrolysis experiments were performed with cellobiohydrolase I (CBH I) and endoglucanase II (EG II) from Trichoderma reesei on a realistic lignocellulose substrates: steam-pretreated willow. The enzymes were studied both alone and in equimolar mixtures. Adsorption isotherms were determined at 4 and 40°C during 90-min reaction times. Both CBH I and EG II adsorbed stronger at 40 than at 4°C. The time course of adsorption and hydrolysis, 3 min to 48 h, was studied at 40°C. About 90% of the cellulases were adsorbed within 2 h. The hydrolysis rate was high in the beginning but decreased during the time course. Based on adsorption data, the hydrolysis and synergism were analyzed as function of adsorbed enzyme. CBH I showed a linear correlation between hydrolysis and adsorbed enzyme, whereas for EG II the corresponding curve leveled off at both 4 and 40°C. At low conversion, below 1%, EG II produced as much soluble sugars as CBH I. At higher conversion, CBH I was more efficient than EG II. The synergism as function of adsorbed enzyme increased with bound enzyme before reaching a stable value of about 2. The effect of varying the ratio of CBH I:EG II was studied at fixed total enzyme loading and by changing the ratio between the enzymes. Only a small addition (5%) of EG II to a CBH I solution was shown to be sufficient for nearly maximal synergism. The ratio between EG II and CBH I was not critical. The ratio 40% EG II:60% CBH I showed similar conversion to 5% EG II:95% CBH I. Modifications of the conventional endo-exo synergism model are proposed. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/125346
- author
- Karlsson, Johan ; Medve, József and Tjerneld, Folke LU
- organization
- publishing date
- 1999
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Trichoderma reesei, cellulase, cellulose hydrolysis, lignocellulose, cellobiohydrolase, endoglucanase, synergism, adsorption
- in
- Applied Biochemistry and Biotechnology
- volume
- 82
- issue
- 3
- pages
- 243 - 258
- publisher
- Humana Press
- ISSN
- 1559-0291
- language
- English
- LU publication?
- yes
- id
- c0fdf3b3-8b48-4cef-b922-cbaf72335579 (old id 125346)
- alternative location
- http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=15304773&dopt=Abstract
- date added to LUP
- 2016-04-01 11:33:48
- date last changed
- 2018-11-21 19:57:55
@article{c0fdf3b3-8b48-4cef-b922-cbaf72335579, abstract = {{The mechanism of hydrolysis of cellulose is important for improving the enzymatic conversion in bioprocesses based on lignocellulose. Adsorption and hydrolysis experiments were performed with cellobiohydrolase I (CBH I) and endoglucanase II (EG II) from Trichoderma reesei on a realistic lignocellulose substrates: steam-pretreated willow. The enzymes were studied both alone and in equimolar mixtures. Adsorption isotherms were determined at 4 and 40°C during 90-min reaction times. Both CBH I and EG II adsorbed stronger at 40 than at 4°C. The time course of adsorption and hydrolysis, 3 min to 48 h, was studied at 40°C. About 90% of the cellulases were adsorbed within 2 h. The hydrolysis rate was high in the beginning but decreased during the time course. Based on adsorption data, the hydrolysis and synergism were analyzed as function of adsorbed enzyme. CBH I showed a linear correlation between hydrolysis and adsorbed enzyme, whereas for EG II the corresponding curve leveled off at both 4 and 40°C. At low conversion, below 1%, EG II produced as much soluble sugars as CBH I. At higher conversion, CBH I was more efficient than EG II. The synergism as function of adsorbed enzyme increased with bound enzyme before reaching a stable value of about 2. The effect of varying the ratio of CBH I:EG II was studied at fixed total enzyme loading and by changing the ratio between the enzymes. Only a small addition (5%) of EG II to a CBH I solution was shown to be sufficient for nearly maximal synergism. The ratio between EG II and CBH I was not critical. The ratio 40% EG II:60% CBH I showed similar conversion to 5% EG II:95% CBH I. Modifications of the conventional endo-exo synergism model are proposed.}}, author = {{Karlsson, Johan and Medve, József and Tjerneld, Folke}}, issn = {{1559-0291}}, keywords = {{Trichoderma reesei; cellulase; cellulose hydrolysis; lignocellulose; cellobiohydrolase; endoglucanase; synergism; adsorption}}, language = {{eng}}, number = {{3}}, pages = {{243--258}}, publisher = {{Humana Press}}, series = {{Applied Biochemistry and Biotechnology}}, title = {{Hydrolysis of Steam-Pretreated Lignocellulose: synergism and adsorption for cellobiohydrolase I and endoglucanase II of Trichoderma reesei.}}, url = {{http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=15304773&dopt=Abstract}}, volume = {{82}}, year = {{1999}}, }