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Subject: Agricultural Biotechnology × Author: SAHA, DIPANKAR × End date: 2019 × Start date: 2019 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    CHARACTERIZATION OF XYLANASE ENZYME FROM FUNGAL STRAINS OF NORTH-EASTERN REGION OF INDIA
    (AAU, Jorhat, 2019) SAHA, DIPANKAR; Boro, R.C.
    Xylanases are hydrolytic enzymes produced by a variety of microorganisms including fungi. The enzyme hydrolyzes the main hemicelluloses component by cleaving the β-1, 4 backbone of the complex plant cell wall polysaccharide xylan. Fungi are reported to produce a wide variety of xylanases that are not only capable of degrading xylan to renewable fuels and chemicals but have also found industrial application in food, paper and pulp industries. In recent years, there has been growing awareness in applying green biotechnology to industrial processes to decrease pollution as well as improve the quality of the product produced. Scouring for readily available and cost-effective source of this enzyme is important in the context of environmental sustainability. The Northeastern region is known for its biodiversity harbors. Several species of fungi whose industrial application or as a source of important products has been reported scantly. The present study focuses on the isolation and characterization of xylanase enzymes from selected fungal isolates of this region. Twenty five (25) previously isolated fungal isolates were taken from the Microbial Biotechnology Lab, Department of Agricultural Biotechnology, Assam Agricultural University, Jorhat for the study.. Preliminaryplate screening of the isolates revealed xylanase activity in four isolates viz. Lentinus squarrosulus, Fusarium oxysporum, Lentinussajor-caju and Fusariumfujikuroi. TheXylanase positive isolates were grownin liquid media and enzyme activity was assayed up to 15 days at a 2 days interval. Highest xylanase activity was recorded on the 7thday of inoculationin Lentinussquarrosulus, Fusarium oxysporum, whereas Fusariumfujikuroiand Lentinus sajor-cajushowed the highest xylanaseactivity on the 5th and 9th day of inoculation respectively. Xylanase enzyme was partially purified from culture supernatant by precipitation using ammonium sulphate (80% saturation). The precipitated crude enzyme was dialyzed against 1mM sodium acetate buffer (pH 5.3).Fusarium oxysporum showed the highest xylanase activity (28.71±0.11 U/mL) in the partially purified extract. Zymogram analysis of partially purified enzymes suggested the presence of single active xylanase in each sample. However, electrophoretic mobility of the xylanase of each sample was different. SDS PAGE analysis indicated the presence of multiple subunits in the xylanase enzyme. Xylanase activity and stability were optimized in different pH and temperatures. All the samples are pH and temperature specific and highly stable at 5.0-6.0 pH and 20oC-50oC. Further studies with improved purification techniques will pave the way for purified xylanase enzyme that may be useful in different industrial purposes.