Alkaline thermostable pectinase enzyme from Aspergillus niger strain MCAS2 isolated from Manaslu Conservation Area, Gorkha, Nepal.

Bhim Prakash Khatri,Jyoti Maharjan,Tribikram Bhattarai,Sangita Shrestha

doi:10.1186/s40064-015-1286-y

Bhim Prakash Khatri, Jyoti Maharjan + Show 2 more

Open Access

https://doi.org/10.1186/s40064-015-1286-y

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Abstract

Pectinase enzymes are one of the commercially important enzymes having great potential in various industries especially in food industry. Pectinases accounts for 25 % of global food enzymes produced and their market is increasing day by day. Therefore, the exploration of microorganism with novel characteristics has always been the focus of the research. Microorganism dwelling in unique habitat may possess unique characteristics. As such, a pectinase producing fungus Aspergillus niger strain MCAS2 was isolated from soil of Manaslu Conservation Area (MCA), Gorkha, Nepal. The optimum production of pectinase enzyme was observed at 48 h of fermentation. The pectinase enzyme was partially purified by cold acetone treatment followed by Sephadex G-75 gel filtration chromatography. The partially purified enzyme exhibited maximum activity 60 U/mg which was almost 8.5-fold higher than the crude pectinase. The approximate molecular weight of the enzyme was found to be 66 kDa as observed from SDS-PAGE. The pectinase enzyme was active at broad range of temperature (30–70 °C) and pH (6.2–9.2). Optimum temperature and pH of the pectinase enzyme were 50 °C and 8.2 respectively. The enzyme was stable up to 70 °C and about 82 % of pectinase activity was still observed at 100 °C. The thermostable and alkaline nature of this pectinase can meet the demand of various industrial processes like paper and pulp industry, in textile industry, fruit juice industry, plant tissue maceration and wastewater treatment. In addition, the effect of different metal ions on pectinase activity was also studied.

Highlights

Pectinase enzymes commonly represent a group of enzymes that involves in degradation of pectin
Considering the importance and application of pectinase enzyme the present study aims to characterize the pectinase enzyme produced by a newly isolated soil fungus, Aspergillus niger strain MCAS2 from the altitude of 3500 m, Manaslu Conservation Area (MCA), Gorkha district of Nepal
The spores of pure culture were maintained in potato dextrose agar (PDA) medium in test tubes sealed with parafilm and stored at 4 °C for further use

Summary

Introduction

Pectinase enzymes commonly represent a group of enzymes that involves in degradation of pectin. The amount of pectic substances present in plant materials varies (0.5– 4.0 % of fresh weight plant material) depending upon the Enzymes are important biocatalyst for various industrial and biotechnological purposes and produced by microorganisms, animal and plant. They can work in many adverse condition compared to chemical catalyst. Microorganisms are preferred as a source of enzyme because of their short life span, high productivity rate, cost effective, and free of harmful chemicals that are found in enzyme from plant and animal source (Chaplin and Bucke 1990). Fifty percent of available enzymes are originated from fungi and yeast; 35 % from bacteria, while the remaining 15 %

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