Pectinases are a complex group of enzymes that degrade various pectic substances present in plant tissues. Pectinases have potential applications in fruit, paper and textile industries. Apart from these industrial applications, these enzymes possess biological importance in protoplast fusion technology and plant pathology. Since applications of pectinases in various fields are widening, it is important to understand the nature and properties of these enzymes for efficient and effective usage. For the past few years, vigorous research has been carried out on isolation and characterization of pectinases. New affinity matrices with improved characteristics and affinity-precipitation techniques have been developed for purification of pectinases. Recently much attention has been focused on chemical modification of pectinases and their catalytic performance by various researchers. These studies are helpful in determining key amino acid residues responsible for substrate binding, catalytic action, and physico-chemical environmental conditions for maximum hydrolysis. This short review highlights progress on purification and understanding the biochemical aspects of microbial pectinases. © 2002 Elsevier Science Ltd. All rights reserved.

Sathyanarayana Naidu Gummadi

Department Of Biotechnology

T Panda

Department Of Chemical Engineering

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Purification and biochemical properties of microbial pectinases—a review

Process Biochemistry

Pectin and other pectic substances are complex polysaccharides, which contribute firmness and structure to plant tissues as a part of the middle lamella. The basic unit in pectic substances is galacturonan (α-D-galacturonic acid). Pectic substances are classified into two types; homogalacturonan and heterogalacturonan (rhamnogalacturonan). In homogalacturonan, the main polymer chain consists of α-D-galacturonate units linked by (1 → 4) glycosidic bonds, whereas in rhamnogalacturonan, the primary chain consist of (1→4) linked α-D-glacturonates and with about 24% L-rhamnose units that are β(1→2) and β(1→4) linked to D-galacturonate units (Whitaker, 1991). The side chains of rhamnogalacturonans usually consist of L-arabinose or D-galacturonic acid units. In plant tissues, about 6070% of the galacturonate units are esterified with methanol and occasionally with ethanol. Based on the degree of esterification, pectic substances are classified into protopectin, pectinic acid, pectin and polygalacturonic acid (Table 1). Molecular size, degree of esterification and weight distribution of polygalacturonic acid residues are important factors that contribute to heterogeneity in pectic substances. Relative molecular masses of pectic substances isolated from various sources such as citrus fruits, apple and plums, range from 25 to 350 kDa. Pectinases are a complex and diverse group of enzymes involved in the degradation of pectic substances. The diversity of forms of pectic substances in plant cells probably accounts for the existence of various forms of these enzymes. Pectinases are classified depending on their substrate and mode of enzymatic reaction (Fig. 1). Pectinases act as carbon recycling agents in nature by degrading pectic substances to saturated and unsaturated galacturonans, which are further catabolized (Table represented) to 5-keto-4-deoxy-uronate and finally to pyruvate and 3-phosphoglyceraldehyde (Vincent-Sealy et al., 1999). Pectinases from phytopathogenic fungi such as Aspergillus flavus, Fusarium oxysporum and Botrytis cinerea are also known to play a vital role in plant pathogenicity or virulence by degrading pectic compounds present in cell wall (Lang and Drenberg, 2000; DiPietro and Roncero, 1996; Ten Have et al., 1998). Pectinases, especially polygalacturonase, is known to play a major role in pectin breakdown during the final stages of fruit ripening (Sozzi- Quiroga and Fraschina, 1997; Chin et al., 1999). Polymethylgalacturonase (PMG), polygalacturonase (PG), pectin lyase (PL), polygalacturonate lyase (PGL) and pectinesterase (PME) are industrially important pectinases discussed in this chapter. © 2007 Springer.

Industrial Enzymes: Structure, Function and Applications

Structural and biochemical properties of pectinases

Debaryomyces nepalensis was previously isolated, which is capable of producing pectin lyase and pectate lyase using pectin as sole source of carbon. The parameters affecting the activity of these enzymes are categorized into two, viz., chemical (amount of substrate and enzyme) and physical (pH of reaction mixture and temperature of incubation). The effect of these parameters on pectin lyase and pectate lyase was studied using central composite design. The optimal conditions of amount of substrate and enzyme (culture broth) were found to be 545 μl (∼1 g/l pectin) and 123 μl for pectin lyase and 707 μl (∼1.1 g/l polygalacturonic acid) and 96 μl for pectate lyase. The optimum pH and temperature for reaction was found to be 6.4 and 35 °C for pectin lyase and 7.5 and 32 °C for pectate lyase. After optimization, the activity of pectin lyase and pectate lyase was increased by 1.3- and 1.4-fold, respectively. © 2006 Elsevier B.V. All rights reserved.

Biochemical Engineering Journal

Optimization of chemical and physical parameters affecting the activity of pectin lyase and pectate lyase from Debaryomyces nepalensis: A statistical approach

Pectic transeliminases, also known as pectic lyases or pectinases, are involved in the degradation of pectic substances. They have a wide range of applications in food and textile processing. Although Aspergillus and Penicillium spp. produce pectin lyases, bacteria are the major producers of polygalacturonate lyase. The yields of pectic transeliminases are less than other pectinases. Since new applications for pectic transeliminases are emerging, an improved process for the production of these enzymes is necessary. © Springer 2005.

Biotechnology Letters

Microbial pectic transeliminases

The understanding that enzymatic degradation of fruit pectin can clarify juices and improve juice yields resulted in the search for microbial pectinases and application in vegetable- and fruit-processing industries. Identified enzymes were classified on the basis of their catalytic activity to pectin or its derivatives and in terms of industrial use. Discovery of gene sequences that coded the enzymes, protein engineering, and molecular biology tools resulted in defined microbial strains that over-produced the enzymes for cost-effective technologies. Recent perspectives on the use of pectin and its derivatives as dietary fibers suggest enzymatic synthesis of the right oligomers from pectin for use in human nutrition. While summarizing the activities of pectin-degrading enzymes, their industrial applications, and gene sources, this review projects another application for pectinases, which is the use of enzymatically derived pectin moieties in functional food preparation.

Annual Review of Food Science and Technology

Potential Application of Pectinase in Developing Functional Foods

The present study deals with the production of cold active polygalacturonase (PGase) by submerged fermentation usingThalassospira frigidphilosprofundus, a novel species isolated from deep waters of Bay of Bengal. Nonlinear models were applied to optimize the medium components for enhanced production of PGase. Taguchi orthogonal array design was adopted to evaluate the factors influencing the yield of PGase, followed by the central composite design (CCD) of response surface methodology (RSM) to identify the optimum concentrations of the key factors responsible for PGase production. Data obtained from the above mentioned statistical experimental design was used for final optimization study by linking the artificial neural network and genetic algorithm (ANN-GA). Using ANN-GA hybrid model, the maximum PGase activity (32.54 U/mL) was achieved at the optimized concentrations of medium components. In a comparison between the optimal output of RSM and ANN-GA hybrid, the latter favored the production of PGase. In addition, the study also focused on the determination of factors responsible for pectin hydrolysis by crude pectinase extracted fromT. frigidphilosprofundusthrough the central composite design. Results indicated 80% degradation of pectin in banana fiber at 20°C in 120 min, suggesting the scope of cold active PGase usage in the treatment of raw banana fibers.

Fulltext

BioMed Research International

Optimization of Polygalacturonase Production from a Newly IsolatedThalassospira frigidphilosprofundusto Use in Pectin Hydrolysis: Statistical Approach

The reaction conditions were optimized for enzymatic hydrolysis of pectic substances using pectolytic enzymes produced by Aspergillus niger NCIM 548. Response surface methodology was used to optimize the reaction parameters and the central composite design was employed for this purpose. Pectin was used as the substrate for polymethylgalacturonase and pectinlyase, whereas polygalacturonic acid was the substrate for polygalacturonase. The volume ratio of reactants for maximum hydrolysis was determined under the assay conditions. The optimum amount of substrate and enzyme were found to be 0.2 cm3 and 0.074 cm3 for polymethylgalacturonase, 0.4 cm3 and 0.086 cm3 for polygalacturonase, and 0.63 cm3 and 0.7 cm3 for pectinlyase. The pH and temperature optima were found to be 5.3 and 30°C for polymethylgalacturonase, 6.6 and 26°C for polygalacturonase, and 4.8 and 35°C for pectinlyase. Under optimized conditions the enzyme activities were higher when compared to unoptimized conditions. Copyright (C) 1999 Elsevier Science Inc.The reaction conditions were optimized for enzymatic hydrolysis of pectic substances using pectolytic enzymes produced by Aspergillus niger NCIM 548. Response surface methodology was used to optimize the reaction parameters and the central composite design was employed for this purpose. Pectin was used as the substrate for polymethylgalacturonase and pectinlyase, whereas polygalacturonic acid was the substrate for polygalacturonase. The volume ratio of reactants for maximum hydrolysis was determined under the assay conditions. The optimum amount of substrate and enzyme were found to be 0.2 cm3 and 0.074 cm3 for polymethylgalacturonase, 0.4 cm3 and 0.086 cm3 for polygalacturonase, and 0.63 cm3 and 0.7 cm3 for pectinlyase. The pH and temperature optima were found to be 5.3 and 30°C for polymethylgalacturonase, 6.6 and 26°C for polygalacturonase, and 4.8 and 35°C for pectinlyase. Under optimized conditions the enzyme activities were higher when compared to unoptimized conditions.

Enzyme and Microbial Technology

Performance of pectolytic enzymes during hydrolysis of pectic substances under assay conditions: A statistical approach

The effect of microbiological parameters, Viz., slant age, inoculum age and amount of inoculum were studied using response surface methodology for the production of pectolytic enzymes, polymethylgalacturonase, polygalacturonase and pectinlyase. The central composite design was used to determine the individual optimum values. Individual optimum values of slant age, inoculum age and amount of inoculum were 49.5 h, 52.3 h and 11.2%, respectively, for polymethylgalacturonase; 62.4 h, 60.5 h and 14.4%, respectively, for polygalacturonase, and 78.3 h, 52.5 h and 1314%, respectively, for pectinlyase. In order to develop a two-stage inoculum possessing the best conditions for the maximum production of all three enzymes, a multiresponse analysis was carried out using a generalized distance approach. The microbiological parameters were optimized simultaneously for maximum production of enzymes. The simultaneous optimal values of slant age, inoculum age and amount of inoculum were 81.4 h, 66.7 h and 15.8%, respectively, for all the three enzymes. After optimization, the fermentation time was reduced from 144 to 120 h.

Multiresponse analysis of microbiological parameters affecting the production of pectolytic enzymes by Aspergillus niger: A statistical view

Hydrolysis of pectic substances by pectinases were carried out under process conditions. Polymethylgalacturonase, polygalacturonase and pectinlyase are three enzymes studies in this regard. Pectin is used as the substrate for polymethylgalacturonase and pectinlyase whereas polygalacturonic acid was used as the substrate for polygalacturonase. The initial concentration was varied between 1.0 and 5.0 kg/m3 for polymethylgalacturonase and polygalacturonase and between 4.0 and 8.0 kg/m3 for pectinylase. Hydrolysis experiments were carried out by varying initial substrate to enzyme ratio and reducing groups formed are measured. The behaviour of pectinases during hydrolysis are studied from the plot of (reducing groups formed)/initial substrate vs. initial substrate to enzyme ratio. This study is helpful in predicting the amount of substrate and enzyme required to produce the required amount of reducing groups within a stipulated time.

Bioprocess Engineering

Behaviour of pectinases under process conditions

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.

Production of pectolytic enzymes - A review

The synthesis of pectinase using Aspergillus niger, NCIM 548, has been enhanced by optimizing the carbon and nitrogen sources present in the medium. Enzyme synthesis was about 40% more using the optimized medium than using the unoptimized medium. The study provided information on the appropriate carbon source as well as the optimum ratio of carbon to nitrogen, yielding the highest enzyme levels.

Journal	Data powered by TypesetProcess Biochemistry
Publisher	Data powered by TypesetElsevier BV
ISSN	13595113
Open Access	No