Biocatalytic activity of Aspergillus niger xylanase in paper pulp biobleaching.

A Sridevi,A Sandhya,G Narasimha,G Ramanjaneyulu,P Suvarnalatha Devi

doi:10.1007/s13205-016-0480-0

Abstract

Xylanase is a hemicellulase enzyme that catalyses the hydrolysis of xylan to xylose which is widely used in processing of feed, pulp and paper. It is produced by many microorganisms especially filamentous fungi like Trichoderma and Aspergillus. A potential xylanolytic fungal isolate Aspergillus niger was isolated from forest soils of Tirumala, AP, India, and its crude enzyme was checked for its potential in paper bleaching. Under submerged fermentation, production of xylanase, cellulase, biomass, total protein and sugar released were analysed after 7 days of incubation at room temperature. Maximum enzyme activity was recorded on the fifth day of incubation, biomass after the seventh day, total protein and sugar released on the sixth day of incubation. Enzyme pretreatment of paper reduced 3.5 points in kappa number, 3.1 points increase in brightness and removal of chromophores and hydrophobic compounds. The FTIR and SEM analysis of enzyme-treated sample had shown modification in surface morphology and functional groups. These results clearly demonstrated that the xylanase produced by A. niger was effective as a pulp biobleaching agent which can be used on an industrial scale.

Highlights

Considerable interest has been focused on the use of hydrolytic enzymes like xylanases that degrade xylan components in plant cell walls into simple sugars
A potential xylanolytic fungal isolate Aspergillus niger was isolated from forest soils of Tirumala, AP, India, and its crude enzyme was checked for its potential in paper bleaching
The FTIR and SEM analysis of enzyme-treated sample had shown modification in surface morphology and functional groups. These results clearly demonstrated that the xylanase produced by A. niger was effective as a pulp biobleaching agent which can be used on an industrial scale

Summary

Introduction

Considerable interest has been focused on the use of hydrolytic enzymes like xylanases that degrade xylan components in plant cell walls into simple sugars. Commercial applications of xylanases include pulp bleaching, food and animal feed industries, fuel, textile industries and in water management They are required in bulk amounts and have significant application in paper and pulp industries as hydrolysis of xylan releases lignin from paper pulp and reduce usage of chemical bleaching agents. The drawback to introduce these environmentally sound technologies in pulp and paper industry is because it is difficult to attain high brightness degree as residual lignin and lignin-derived compounds that are more recalcitrant to degradation in TCF bleaching. To overcome these difficulties, enzymatic biobleaching using xylanases and laccases is an efficient alternative in many industrial applications. The ability of xylanases to facilitate the bleaching of kraft pulp was first

Methods

Results

Conclusion