Studies on pH and thermal deactivation of pectolytic enzymes from Aspergillus niger
TL;DR: The addition of protein doubled the half-life times of partially purified PMG, PG I and PG II and the interaction effect of pectolytic enzymes on deactivation was found to be significant.
About: This article is published in Biochemical Engineering Journal.The article was published on 2003-10-01. It has received 108 citations till now.
Citations
More filters
TL;DR: Departamento de Bioquimica e Microbiologia Instituto de Biociencias Universidade Estadual Paulista, UNESP, Avenida 24A, 1515, CEP 13506-900 Rio Claro, SP
Abstract: Departamento de Bioquimica e Microbiologia Instituto de Biociencias Universidade Estadual Paulista, UNESP, Avenida 24A, 1515, CEP 13506-900 Rio Claro, SP
284 citations
TL;DR: This paper provides a bird’s eye view of the possible application of these enzymes in commercial sector and the molecular characterization of pectinolytic enzymes.
Abstract: Today pectinases are upcoming industrially important bacterial enzymes. It can be produced by a variety of microorganisms. These enzymes act on pectin, which is the major component of middle lamella in plant cell wall. Pectinolytic enzymes are classified according to their mode of attack on the galacturonan part of the pectin molecules such as protopectinases, esterase’s and depolymerases. As we know that microbial enzymes work depends up on the type of enzymes application, temperature, concentration, and pH and so on, therefore, pectinase enzyme also differentiated according to their physical and chemical factors too. The biochemical structures of pectinases include members of all the major classes and the structure–function relationship, studies of a few available complexes of pectinases with substrate/analogs could be considered as prototypes for related family member and the molecular characterization of pectinolytic enzymes is also well documented. Furthermore, it provides a bird’s eye view of the possible application of these enzymes in commercial sector.
127 citations
TL;DR: The purified L-asparaginase has no partial glutaminase activity, which can reduce the possibility of side effects during the course of anti-cancer therapy, and is moderately inhibited by various divalent cations and thiol group blocking reagents.
124 citations
Cites methods from "Studies on pH and thermal deactivat..."
...The energies and entropies of deactivation can be estimated by making use of absolute reaction rates (Eyring, 1991; Naidu and Panda, 2003)....
[...]
...This is called single step two-stage theory (Sadana, 1991; Naidu and Panda, 2003)....
[...]
TL;DR: In this article, thermal inactivation curves were not linear in the range 40-60 °C and the optimum pH for enzyme activity was 4.7 for Pectinex 3XL and 4.0 for both Rapidase C80 and Pectinase CCM.
123 citations
TL;DR: In this article, pectinases-producing filamentous fungi were isolated with the aim of using their enzymes in the clarification of apple and blueberry juices, and the experimental extract enzyme EE obtained in solid-state process with a strain identified as belonging to the species Aspergillus niger and designated LB23 was used for treating juices and compared with two commercial enzyme preparations.
Abstract: In this work, pectinases-producing filamentous fungi were isolated with the aim of using their enzymes in the clarification of apple and blueberry juices. The experimental extract enzyme EE obtained in solid-state process with a strain identified as belonging to the species Aspergillus niger and designated LB23 was used for treating juices and compared with two commercial enzyme preparations: Pectinex ® Clear (PC) for apple juice, and Pectinex ® BE Color (PB) for blueberry juice. After the enzymatic treatment, the treated juices were evaluated with respect to parameters such as viscosity, turbidity, and degree of clarification, as well as antioxidant capacity, and total phenolic compound content. Considering all comparison criteria, the experimental preparation EE showed results statistically similar or superior to those obtained with the commercial enzyme preparations.
78 citations
References
More filters
TL;DR: Genetic and enzyme engineering studies are promising in terms of enhancing conformational stability, but are likely to require case-by-case knowledge of the enzyme concerned, and stability enhancements achieved so far are relatively small.
140 citations
TL;DR: In this article, a review of the production of pectolytic enzymes using different carbon sources is presented and the effect of operating parameters such as temperature, aeration rate, agitation and type of fermentation is discussed.
Abstract: Pectolytic enzymes play an important role in food processing industries and alcoholic beverage industries. These enzymes degrade pectin and reduce the viscosity of the solution so that it can be handled easily. These enzymes are mainly synthesized by plants and microorganisms. Aspergillus niger is used for industrial production of pectolytic enzymes. This fungus produces polygalacturonase, polymethylgalacturonase and pectinlyase. This review mainly concerns with the production of pectolytic enzymes using different carbon sources. It also deals with the effect of operating parameters such as temperature, aeration rate, agitation and type of fermentation on the production of these enzymes.
126 citations
TL;DR: Dynamic drainage jar experiments show that the enzyme treatment improves the effectiveness of several cationic polymers to increase retention of fines and filler particles and does not damage the strength properties of the pulp.
125 citations
TL;DR: Observations suggest that alpha-helix rigidity can affect reversible and irreversible glucoamylase stability differently, that the effects of multiple mutations within one alpha- Helix to improve stability are not always additive and that even single mutations can strongly affect extracellular enzyme production.
Abstract: To decrease irreversible thermoinactivation of Aspergillus awamori glucoamylase, five Gly residues causing helix flexibility were replaced with Ala residues. Mutation of Gly57 did not affect thermostability. Mutation of Gly137 doubled it at pHs 3.5 and 4.5 but barely changed it at pH 5.5. The Gly139-->Ala mutation did not change thermostability at pH 3.5, improved it at pH 4.5 and worsened it at pH 5.5. The Gly 137/Gly139-->Ala/Ala mutation gave 1.5-2-fold increased thermostabilities at pHs 3.5-5.5. Mutations of Gly251 and Gly383 decreased it at all pHs. Gly137-->Ala and Gly137/Gly139-->Ala/Ala glucoamylases are the most stable yet produced by mutation. Guanidine treatment at pH 4.5 decreased the reversible stabilities of Gly137-->Ala, Gly139-->Ala and Gly137/Gly139-->Ala/Ala glucoamylases at infinite dilution while not changing those of Gly251-->Ala and Gly383-->Ala glucoamylases, which is, in general, opposite to what occurred with thermoinactivation. Mutation of Gly57 greatly improved the extracellular glucoamylase production by yeast, that of Gly137 barely affected it and those of Gly139 and of both Gly137 and Gly139 strongly impeded it. These observations suggest that alpha-helix rigidity can affect reversible and irreversible glucoamylase stability differently, that the effects of multiple mutations within one alpha-helix to improve stability are not always additive and that even single mutations can strongly affect extracellular enzyme production.
74 citations
TL;DR: Modification of carboxyl groups with EDC in the presence of ethylenediamine leading to the transformation of three car boxyl groups to amino groups increased the thermostability of the enzyme for temperatures above the temperature of compensation, Tc, which is 60 degrees C.
52 citations