Immobilization of Fungal β-Glucosidase on Silica Gel and Kaolin Carriers

Karagulyan, Hakob K.; Gasparyan, Vardan K.; Decker, Stephen R.

doi:10.1007/978-1-60327-526-2_18

Cited by 7 publications

(16 citation statements)

References 14 publications

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“…On the other hand, the highest retained activity (60.3%) and bound enzyme (30.1 U/g carrier) were found with sponge. Karagulyan et al (2008) reported that physical adsorption of fungal β-glucosidase on kaolin involved weak and non-stable bonds between enzyme and carrier.…”

Section: Immobilization By Physical Adsorptionmentioning

confidence: 99%

“…β-Glucosidase (β-D-glucoside glucohydrolases, cellobiase E.C.3.2.1.21) is a key enzyme in the hydrolysis of cellulose to two glucoses (Karagulyan et al, 2008). β-Glucosidase also demonstrated activity on cello-oligomers and, although the activity varies, it generally decreases with increasing chain length.…”

Section: Introductionmentioning

confidence: 99%

“…β-Glucosidase can be used in the production of aromatic compounds, in the stabilization of juices and beverages, and in the improvement of the organoleptic properties of food and feed products. It is also used in biomass degradation and in the production of fuel ethanol from cellulosic agricultural residues (Saha, et al, 1994;Ortega et al, 1998;Karagulyan et al, 2008;Saritha and Lata 2012). Moreover, it can be used in the synthesis of alkyl-and aryl glycosides from natural polysaccharides or their derivatives and alcohols by reverse hydrolysis or trans-glycosylation, leading to products with applications in pharmaceutical, cosmetic, and detergent industries (Gueguen et al, 1999;Bhatia et al, 2002;Yeoman et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, it can be used in the synthesis of alkyl-and aryl glycosides from natural polysaccharides or their derivatives and alcohols by reverse hydrolysis or trans-glycosylation, leading to products with applications in pharmaceutical, cosmetic, and detergent industries (Gueguen et al, 1999;Bhatia et al, 2002;Yeoman et al, 2010). The cellulase complex from the main fungal producers normally contain small amounts of β-glucosidase, which may limit the overall cellulose hydrolysis rate, as cellobiose inhibits activity of other enzymes of the cellulose complex (Karagulyan et al, 2008). β-Glucosidase is also subject to end-product inhibition, with removal of glucose significantly enhancing the enzyme activity rate (Ortega et al, 1998;Karagulyan et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…The cellulase complex from the main fungal producers normally contain small amounts of β-glucosidase, which may limit the overall cellulose hydrolysis rate, as cellobiose inhibits activity of other enzymes of the cellulose complex (Karagulyan et al, 2008). β-Glucosidase is also subject to end-product inhibition, with removal of glucose significantly enhancing the enzyme activity rate (Ortega et al, 1998;Karagulyan et al, 2008). The cost of β-glucosidase-based technology can be reduced by increasing the enzyme reusability and its stability (AbdEl-Ghaffar and Hashem, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Biochemical studies on immobilized fungal β-glucosidase

Ahmed

El-Shayeb

Hashem

et al. 2013

Braz. J. Chem. Eng.

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-β-Glucosidase from Aspergillus niger was immobilized on sponge by covalent binding through a spacer group (glutaraldehyde). Sponge-immobilized enzyme had the highest immobilization yield (95.67%) and retained 63.66% of the original activity exhibited by the free enzyme. The optimum pH of the immobilized enzyme remains almost the same as for the free enzyme (pH 4.0). The optimum temperature for β-glucosidase activity was increased by 10 ºC after immobilization. The activation energy (E a ) of the immobilized β-glucosidase was lower than the free enzyme (3.34 and 4.55 kcal/mol), respectively. Immobilized β-glucosidase exhibited great thermal stability and retained all the initial activity after incubation at 55 ºC for 2 h; however, the free enzyme retained 89.25% under the same condition. The calculated half-life (t ½ ) value of heat inactivation of immobilized enzyme at 60, 65 and 70 ºC was 213.62, 72.95 and 56.80 min, respectively, whereas at these temperatures the free enzyme was less stable (half-life of 200.0, 55.31 and 49.5 min, respectively). The deactivation rate constant at 65 ºC for the immobilized β-glucosidase is 9.5x10 -3 / min, which was lower than that of the free form (12.53x10 -3 / min). The immobilization process improved the pH stability of the enzyme (immobilized and free enzyme retained 69.35 and 39.86%, respectively, of their initial activity after 45 min at pH 7.5). The effect of some chemical substances on the activity of the immobilized and free β-glucosidase has been investigated. In the presence of sodium dodecyl sulfate (SDS) and p-chloromercuri benzoate (p-CMB) the immobilized enzyme retained 36.13 and 45.34%, respectively, of the initial activity, which is higher than that of free enzyme (13.71 and 1.61%, respectively). The Michaelis constant (K m ) value of the free enzyme was 40.0 mM, while the apparent K m value for the immobilized enzyme was 46.51 mM. The maximum reaction rate (v max ) of immobilized β-glucosidase was smaller than that of the free enzyme by 7.69%. Sponge-immobilized β-glucosidase was repeatedly used to hydrolyze cellobiose (5 and 8 cycles with retained activity of 67.32 and 51.04%, respectively).

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Section: Immobilization By Physical Adsorptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Biochemical studies on immobilized fungal β-glucosidase

Ahmed

El-Shayeb

Hashem

et al. 2013

Braz. J. Chem. Eng.

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Nanomaterial Biosynthesis and Enzyme Immobilization

Indu

Yadav

Mandal

et al. 2020

Green Synthesis of Nanomaterials for Bioenergy Applications

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Evaluation of nanoparticle‐immobilized cellulase for improved ethanol yield in simultaneous saccharification and fermentation reactions

Lupoi

Smith

2011

Biotech & Bioengineering

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Ethanol yields were 2.1 (P = 0.06) to 2.3 (P = 0.01) times higher in simultaneous saccharification and fermentation (SSF) reactions of microcrystalline cellulose when cellulase was physisorbed on silica nanoparticles compared to enzyme in solution. In SSF reactions, cellulose is hydrolyzed to glucose by cellulase while yeast simultaneously ferments glucose to ethanol. The 35°C temperature and the presence of ethanol in SSF reactions are not optimal conditions for cellulase. Immobilization onto solid supports can stabilize the enzyme and promote activity at non-optimum reaction conditions. Mock SSF reactions that did not contain yeast were used to measure saccharification products and identify the mechanism for the improved ethanol yield using immobilized cellulase. Cellulase adsorbed to 40 nm silica nanoparticles produced 1.6 times (P = 0.01) more glucose than cellulase in solution in 96 h at pH 4.8 and 35°C. There was no significant accumulation (<250 µg) of soluble cellooligomers in either the solution or immobilized enzyme reactions. This suggests that the mechanism for the immobilized enzyme's improved glucose yield compared to solution enzyme is the increased conversion of insoluble cellulose hydrolysis products to soluble cellooligomers at 35°C and in the presence of ethanol. The results show that silica-immobilized cellulase can be used to produce increased ethanol yields in the conversion of lignocellulosic materials by SSF.

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Immobilization of Fungal β-Glucosidase on Silica Gel and Kaolin Carriers

Cited by 7 publications

References 14 publications

Biochemical studies on immobilized fungal β-glucosidase

Biochemical studies on immobilized fungal β-glucosidase

Nanomaterial Biosynthesis and Enzyme Immobilization

Evaluation of nanoparticle‐immobilized cellulase for improved ethanol yield in simultaneous saccharification and fermentation reactions

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