Abstract:
:The rate of celluose degradation, limited due to the inhibition by cellobiose, can be increased by the hydrolysis of cellobiose to glucose using immobilized beta-glucosidase. Production of beta-glucosidase in four yeasts was studied and a maximum activity of 1.22 IU/mg cells was obtained in cells of Pichia etchellsii when grown on 3% cellobiose as the sole carbon source. A study of the immobilization of beta-glucosidase containing cells of Pichia etchellsii on various solid supports was conducted and immobilization by entrapment in calcium alginate gel beads was found to be the most simple and efficient method. A retention of 96.5% of initial activity after ten sequential batch uses of the immobilized preparation was observed. The pH and temperature optima for free and immobilized cells were the same, i.e., 6.5 (0.05M Maleate buffer) and 50 degrees C, respectively. Even though the temperature optimum was found to be 50 degrees C, the enzyme exhibits a better thermal stability at 45 degrees C. Beads stored at 4 degrees C for six months retain 80% of their activity. Kinetic studies performed on free and immobilized cells shown that glucose is a noncompetitive product inhibitor.The immobilized preparation was found to be limited by pore diffusion but exhibited no film-diffusion resistance during packed bed column indicated by a low dispersion number of 0.1348. A model for reaction with pore diffusion for a noncompetitive type of inhibited system was developed and applied to the cellobiose hydrolysis system. The rate of reaction with diffusional limitations was determined by using the model and effectiveness factors were calculated for different particle sizes. An effectiveness factor of 0.49 was obtained for a particle diameter of 2.5 mm. The modified rate expression using the effectiveness factor represented batch and packed bed reactor operation satisfactorily. The productivity in the packed bed column was found to fall rapidly with increase in conversion rate indicating that the operating conditions of the column would have to be a compromise between high conversion rates and reasonable productivity. A half-life of over seven days was obtained at the operating temperature of 45 degrees C in continuous operation of the packed bed reactor. However, the half-life in the column was found to be greatly affected by temperature, increasing to over seventeen days at a temperature of 40 degrees C and decreasing to less than two days at 50 degrees C.
journal_name
Biotechnol Bioengjournal_title
Biotechnology and bioengineeringauthors
Jain D,Ghose TKdoi
10.1002/bit.260260408subject
Has Abstractpub_date
1984-04-01 00:00:00pages
340-6issue
4eissn
0006-3592issn
1097-0290journal_volume
26pub_type
杂志文章abstract::A microarray presenting glycerol nanodroplets of fluorogenic peptide substrates was used as a biosensor for the detection of multiple enzyme activities within human plasma. Using 10 different plasma proteases (kallikrein, factor XIIa, factor XIa, factor IXa, factor VIIa, factor Xa, thrombin, activated protein C, uPA a...
journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20927
更新日期:2006-08-20 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.27077
更新日期:2019-09-01 00:00:00
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journal_title:Biotechnology and bioengineering
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journal_title:Biotechnology and bioengineering
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260440113
更新日期:1994-06-05 00:00:00
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journal_title:Biotechnology and bioengineering
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doi:10.1002/bit.22768
更新日期:2010-08-15 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260480619
更新日期:1995-12-20 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260370808
更新日期:1991-04-05 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22558
更新日期:2010-02-15 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.22084
更新日期:2009-02-01 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260170802
更新日期:1975-08-01 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260450512
更新日期:1995-03-05 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260190209
更新日期:1977-02-01 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20482
更新日期:2005-06-30 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260380404
更新日期:1991-08-05 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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更新日期:1989-08-20 00:00:00
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journal_title:Biotechnology and bioengineering
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更新日期:1993-07-01 00:00:00
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更新日期:2007-01-01 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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更新日期:1976-02-01 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.20365
更新日期:2005-03-20 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260440203
更新日期:1994-06-20 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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更新日期:2008-04-15 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/(sici)1097-0290(19990420)63:2<233::aid-bit
更新日期:1999-04-20 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
doi:10.1002/bit.260361007
更新日期:1990-12-05 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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更新日期:2005-03-05 00:00:00
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journal_title:Biotechnology and bioengineering
pub_type: 杂志文章
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更新日期:1992-02-05 00:00:00