SRIKANT, GUNJAN GOEL AND VIKAS BENIWAL*
Department of Biotechnology, Maharishi Markandeshwar University, Mullana-133 207, Ambala (Haryana), India
*(e-mail : beniwalvikash@gmail.com; Mobile : 911731274375)
(Received : August 7, 2019; Accepted : October 11, 2019)
ABSTRACT
Xylanases scientifically known as endo-1, 4-β-xylanase (EC 3.2.1.8) are hydrolytic enzymes which cleave the β-1, 4 backbone of the complex plant cell wall polysaccharide xylan. Xylanases are produced by a variety of microorganisms including bacteria, actinomycetes, yeast and fungi. The aim of the present study was isolation and screening of potent xylanase producing bacteria. A total of 68 bacterial isolates were isolated from 40 samples including eight samples from soil of Ballarpur Paper Industries Pvt. Ltd, 16 samples from forestland of National Forest Kalesar and 16 samples from agricultural land. Among these, only 18 isolates were found to be showing clear and transparent zone of hydrolysis (6-23 mm) during qualitative plate assay performed by congo- red staining. Quantitative assay using DNSA (3,5-Dinitrosalicylic
acid) method revealed that only eight isolates produced xylanase in a range of 204-355U/ml. The isolate XPB 9 resulted in maximum amount of xylanase (355 U/ml) and did not show any cellulase activity with CM cellulose. The selected isolate a gram positive, moderate thermophile with optimum, minimum and maximum temperature for growth at 40, 30 and 60°C, respectively, under sumberged fermentation (SmF) was identified as Bacillus cereus.
Key words : Xylanase, xylan, Bacillus cereus, xylopyranose, congo red