Thermal stability and energy of deactivation of free and immobilized cellobiase

Calsavara, Luiza P. V.; Moraes, Flávio Faria de; Zanin, Gisella Maria

doi:10.1590/s0104-66322000000400047

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…Experiments for the determination of thermal deactivation parameters were carried out at pH 4.5. From the experimental data on the effect of temperature on the activity of the enzyme formulations, the best fit for thermal deactivation was screened between the exponential decay and linear inverted models, according to standard methodologies as described in detail elsewhere. , …”

Section: Methodsmentioning

confidence: 99%

“…From the experimental data on the effect of temperature on the activity of the enzyme formulations, the best fit for thermal deactivation was screened between the exponential decay and linear inverted models, according to standard methodologies as described in detail elsewhere. 39,40 Repeated Batch Hydrolysis. Reactions were performed in a 2 mL screw-capped magnetically stirred (400 rpm) eppendorf at 50 °C, in 1.5 mL of 50 mM acetate buffer (pH 4.5), containing 1.5 mM of cellobiose and 10 mg of immobilized β-glucosidase.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Establishing the Feasibility of Using β-Glucosidase Entrapped in Lentikats and in Sol–Gel Supports for Cellobiose Hydrolysis

Figueira

Sato

Fernandes

2013

J. Agric. Food Chem.

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β-Glucosidases represent an important group of enzymes due to their pivotal role in various biotechnological processes. One of the most prominent is biomass degradation for the production of fuel ethanol from cellulosic agricultural residues and wastes, where the use of immobilized biocatalysts may prove advantageous. Within such scope, the present work aimed to evaluate the feasibility of entrapping β-glucosidase in either sol-gel or in Lentikats supports for application in cellobiose hydrolysis, and to perform the characterization of the resulting bioconversion systems. The activity and stability of the immobilized biocatalyst over given ranges of temperature and pH values were assessed, as well as kinetic data, and compared to the free form, and the operational stability was evaluated. Immobilization increased the thermal stability of the enzyme, with a 10 °C shift to an optimal temperature in the case of sol-gel support. Mass transfer hindrances as a result of immobilization were not significant, for sol-gel support. Lentikats-entrapped glucosidase was used in 19 consecutive batch runs for cellobiose hydrolysis, without noticeable decrease in product yield. Moreover, encouraging results were obtained for continuous operation. In the overall, the feasibility of using immobilized biocatalysts for cellobiose hydrolysis was established.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Establishing the Feasibility of Using β-Glucosidase Entrapped in Lentikats and in Sol–Gel Supports for Cellobiose Hydrolysis

Figueira

Sato

Fernandes

2013

J. Agric. Food Chem.

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“…For thermostability, lipase was incubated at different temperatures (50–80 °C) for 120 min in Tris‐Cl buffer (pH 9) and residual activity measured at 30 min intervals. Half‐lives of lipase at different temperatures were calculated according to Calsavara et al …”

Section: Methodsmentioning

confidence: 99%

A thermo‐alkaline lipase from a new thermophile Geobacillus thermodenitrificans AV‐5 with potential application in biodiesel production

Christopher

Zambare²,

Zambare

et al. 2015

J of Chemical Tech & Biotech

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BACKGROUND: A thermophilic lipase-producing Geobacillus thermodenitrificans strain AV-5 was isolated from the Mushroom Spring of Yellowstone National Park in WY, USA and studied as a source of lipase for transesterification of vegetable oils to biodiesel. RESULTS:A maximum activity of 330 U mL −1 was produced on 2% (v/v) waste cooking oil at 50 ∘ C, pH 8, aeration rate of 1 vvm and agitation speed of 400 rpm. However, the higher lipase productivity (14.04 U mL −1 h −1 ) was found at a volumetric oxygen transfer coefficient (k L a) value of 18.48 h −1 . The partially purified lipase had a molecular weight, temperature and pH optimum of 50 kDa, 65 ∘ C and pH 9, respectively, and was thermo-alkali stable: at 70 ∘ C, it retained 81% activity and 45% stability; at pH 10 it lost only 15% and 2.6% of its maximum activity and stability, respectively. Enzyme kinetic studies with p-nitrophenyl laurate as substrate revealed high substrate specificity (k m of 0.440 mmol L −1 ) and kinetic activity (v max of 556 nmol mL min −1 ) of lipase. CONCLUSIONS: The k L a was found to be highly dependent on aeration and agitation rates. Following optimization of fermentation medium and parameters, a 7.5-fold increase in lipase production by G. thermodenitrificans was attained. The lipase activity and substrate specificity (as k m ) are among the highest reported in the literature for bacterial lipases. It was demonstrated that the enzyme can produce biodiesel from waste cooking oil with a conversion yields of 76%. Fermentation studies on lipase productionEffect of temperature and pH on lipase production Bacterial lipases are greatly influenced by physical fermentation parameters such as temperature and pH. Most thermophilic aerobic geobacilli have optimal growth and enzyme production in

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Characterization of a commercial cellulase for hydrolysis of agroindustrial substrates

Balsan

Astolfi

Benazzi

et al. 2012

Bioprocess Biosyst Eng

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This work is focused on the characterization of a commercial cellulase in terms of optimum pH and temperature, stability to pH and temperature and affinity of this enzyme to several substrates, determining the Michaelis-Menten parameters. Maximum activity of cellulase was obtained for the temperature range from 40 to 50 °C and pH from 5.2 to 5.5. Enzyme activity decreased only 15% after 150 h of reaction at temperatures between 30 and 50 °C. No loss of activity was observed at pH 5.0 and 5.5. The cellulase showed satisfactory results in the hydrolysis of agroindustrial substrates, since similar activity was verified on filter paper and other agroindustrial substrates.

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Thermal stability and energy of deactivation of free and immobilized cellobiase

Cited by 9 publications

References 11 publications

Establishing the Feasibility of Using β-Glucosidase Entrapped in Lentikats and in Sol–Gel Supports for Cellobiose Hydrolysis

Establishing the Feasibility of Using β-Glucosidase Entrapped in Lentikats and in Sol–Gel Supports for Cellobiose Hydrolysis

A thermo‐alkaline lipase from a new thermophile Geobacillus thermodenitrificans AV‐5 with potential application in biodiesel production

Characterization of a commercial cellulase for hydrolysis of agroindustrial substrates

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