Production, Purification and Physicochemical Properties of an Exo‑Polygalacturonase from Aspergillus niger SW06

Ma, Yong; He, Hao; Chen, Zhifei; Zhao, Zhiwei; Shunhui, Chen; Sun, Siwen; Xu, Chunping

doi:10.21577/0103-5053.20160210

Cited by 2 publications

(3 citation statements)

References 24 publications

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“…The effect of enzyme extract concentration on enzyme stability may come from different facts: if the enzyme is multimeric and the first step of the inactivation is enzyme dissociation (but in this case the enzymes are described to be monomeric), if there are some enzyme–enzyme interactions with effect on enzyme stability (e.g., favoring inactivation by aggregation, or stabilizing the enzymes by forming some enzyme complexes), or if some component of the extract may have some effect on enzyme stability (some stabilizing reagent). To evaluate the effect of enzyme concentration on inactivation, two solutions with 1% (0.05 mg mL −1 of protein) and 10% (0.5 mg mL −1 of protein) of enzyme preparation were incubated at pH 10 at 4°C for PE, PG, and PL, at 25°C for PME and 50°C for CE.…”

Section: Resultsmentioning

confidence: 99%

“…The effect of enzyme extract concentration on enzyme stability may come from different facts: if the enzyme is multimeric and the first step of the inactivation is enzyme dissociation (but in this case the enzymes are described to be monomeric), [83][84][85][86][87] if there are some enzyme-enzyme interactions with effect on enzyme stability third sample for each enzyme was prepared with 1% enzyme preparation plus 9% inactivated enzyme solution after boiling. We cannot find any significant difference on the inactivation courses of all these preparations ( Figure 5).…”

Section: Influence Of the Enzyme Concentration On The Stability Of mentioning

confidence: 99%

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Stability/activity features of the main enzyme components of rohapect 10L

Magro

Kornecki

Klein

et al. 2019

Biotechnology Progress

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Rohapect 10L is an enzyme cocktail commercialized for juice clarification. Here, we characterized the activity and stability of five enzymatic activities present in this cocktail: total pectinase (PE), polygalacturonase (PG), pectin lyase (PL), pectin methyl esterase (PME), and total cellulase (CE) activities. All these enzyme activities have the maximum activity and stability at pH 4, conditions near those found in most fruit juices. However, if the enzymes need to be handled under different conditions (e.g., to immobilize them), their stability becomes extremely low in some cases, just at pH values slightly higher than the optimal one. For example, at pH 10 only CE was reasonably stable at 25°C, while many other enzyme activities were rapidly almost inactivated, even at 4°C. For these cases, different additives were evaluated, and we found that polyethylene glycol was positive or very positive for all enzyme stabilities, allowing keeping reasonable activities after several hours at pH 10 and 25°C. Another additive, that is, dextran, has a small positive effect for PE, PG, and CE, and a very positive effect for PL, albeit significantly destabilizing PME. Thus, the handling and use of this extract requires some care when is performed out of optimal conditions.

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Section: Resultsmentioning

confidence: 99%

“…The effect of enzyme extract concentration on enzyme stability may come from different facts: if the enzyme is multimeric and the first step of the inactivation is enzyme dissociation (but in this case the enzymes are described to be monomeric), [83][84][85][86][87] if there are some enzyme-enzyme interactions with effect on enzyme stability third sample for each enzyme was prepared with 1% enzyme preparation plus 9% inactivated enzyme solution after boiling. We cannot find any significant difference on the inactivation courses of all these preparations ( Figure 5).…”

Section: Influence Of the Enzyme Concentration On The Stability Of mentioning

confidence: 99%

Stability/activity features of the main enzyme components of rohapect 10L

Magro

Kornecki

Klein

et al. 2019

Biotechnology Progress

View full text Add to dashboard Cite

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“…In addition, the pore size of Fe 2 O 3 -PVA catalyst is much larger than that of the Fe 2 O 3 catalyst (inset of Figure 1 and Table 1). According to the data in Table 1 21,22 but they possess larger pore size, which helps the diffusion of products.…”

Section: Catalytic Activitymentioning

confidence: 99%

Effect of PVA Concentration on Structure and Performance of Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

Dong

Liu

et al. 2017

J. Braz. Chem. Soc.

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Fe 2 O 3 catalysts were prepared by co-precipitation method with the assistance of polyvinyl alcohol (PVA) for Fischer-Tropsch synthesis. Effects of PVA concentration on structure and performance of the catalyst were investigated in a fixed reactor at 230-310 °C, 1.5 MPa, 2000 h -1 , and syngas H 2 /CO = 2.0. The catalysts were characterized by N 2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), H 2 or CO temperature-programmed reduction (TPR) and H 2 temperature-programmed desorption (H 2 -TPD), Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA). It was found that there was strong interaction between Fe and PVA, which controlled the structure of the catalyst. Among the catalysts investigated, the catalyst prepared with 15 wt.% PVA exhibited better catalytic performance due to the dispersion of iron oxides and the formation of the more active phase on the catalyst. Meanwhile, this catalyst showed the high selectivity to heavy hydrocarbons and satisfactory thermal stability.Keywords: Fischer-Tropsch synthesis, iron-based catalyst, PVA concentration, structure, stability IntroductionFischer-Tropsch synthesis (FTS), an efficient technology to convert syngas into liquid fuels and chemicals, has attracted great interest due to the shrinking of the petroleum resource in the past decades.1 Iron-based catalysts have attracted considerable focus, thanks to their low cost, high activity and excellent water-gas-shift reactivity, which match coal gasification with low H 2 /CO ratio. 2 Remarkably, three principal challenges are posed for iron-based FTS catalyst: activity, selectivity and stability. 3 It is well known that the activity, selectivity and stability of FTS catalysts rely strongly on the texture and surface properties of the resultant catalysts. 4 Most of all, the pore size of catalyst is one of the key factors, which has significant effect on the mass transfer of reactants and products, 5 the re-adsorption of the α-alkene, and the chemisorption ratio of H 2 on the surface active sites exposed. 6 Therefore, these factors are vital for the performance of catalyst in the FTS. For instance, smaller pore size of catalyst can afford high Brunauer, Emmett and Teller (BET) surface area and dispersion of the catalyst. However, diffusion effects of products were limited, resulting in light hydrocarbons as the main product for excessive hydrogenation. In contrast, the larger pore size of catalyst can facilitate the diffusion of products, and thus products of heavy hydrocarbons are obtained.7 Tao et al. 8 proposed that the FTS catalytic activity and product selectivity rely strongly on the pore size distribution of the catalysts. Xiong et al. 9 found that CO conversion increased and then decreased with the pore size in the range studied. Sun and co-workers 10,11 reported that the FTS catalytic performances were closely correlated to the pore sizes of the mesoporous zirconia.In general, the preparation process has a significant e...

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Production, Purification and Physicochemical Properties of an Exo‑Polygalacturonase from Aspergillus niger SW06

Cited by 2 publications

References 24 publications

Stability/activity features of the main enzyme components of rohapect 10L

Stability/activity features of the main enzyme components of rohapect 10L

Effect of PVA Concentration on Structure and Performance of Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis

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