Optimal Conditions For Production Acidic D-Xylanase By Aspergillus niger in Submerged Fermentation

Muhamed Omar Abdulatif,Hyder H Assmaeel,Raghad Kadhim Obeid,Ayat Adnan Abbas

doi:10.24126/jobrc.2011.5.3.174

Abstract

he Xylanase producing strain Aspergillus niger was isolated from soil on potato dextrose agar in the presence of xylan as its first substrate for primary isolation, and then grown under liquid medium fermentation in the presence of crude xylan (rice husk) to produce D-Xylanase. the optimum conditions were determined as follows: the Optimum pH for xylanase production was found pH 5.0, xylanase was induced by xylan (rice husk) 0.1% and the production was (61.221 U/ml) and nitrogen source Yeast extract recorded highest enzyme production( 89.71 U/ml), and repressed by carbon source xylose the highest enzyme production (88.69 U/ml). The optimum temperature was 40°с for xylanase production was (35.15 U/ml), the optimum period after 7 days of incubation was (52.33 U/ml) ,the optimum substrate concentration 0.1% was (45.95 U/ml), and the optimum inoculum size was 1 x 106 (spore /ml) recorded (57.19 U/ml ).

Highlights

Xylan is the major hemicellulose constituent of hard wood and soft wood, and is the most abundant renewable polysaccharide after cellulose
The reaction was stopped by addition of 1.5 ml of 3, 5-dinitrosalicylic acid (DNS) and the contents were boiled for 5 min [8]
Effect of pH on xylanase production The results showed that xylanase production by A. niger was very much dependent on pH, and the optimum initial pH was between pH (5, 6) Figure (1)

Summary

Introduction

Xylan is the major hemicellulose constituent of hard wood and soft wood, and is the most abundant renewable polysaccharide after cellulose. PH optimum The optimum pH of the acidic D- xylanase enzyme production was determined by using different pH (4.0, 5.0, 6.0, 7.0, 8.0) after fixation the rest factors. 2. Nitrogen source The nitrogen source optimum of D- xylanase enzyme production was determined by using different nitrogen sources (2.5 g.L-1) (peptone, ammonium nitrate, yeast extract, ammonium sulphate and urea) after fixation the rest factors.

Results

Conclusion