Isolation and Screening of Aspergillus niger Isolates for Xylanase Biosynthesis

Present investigation deals with the isolation and screening of Aspergillus niger isolates for the biosynthesis of xylanase. About 104 different strains of Aspergillus niger were isolated from soil collected from different areas of Lahore by serial dilution method on xylene agar malt extract medium. The strains with larger whitish zones of xylene hydrolysis were picked up and transferred to the PDA slants. The cultures were incubated at 30 C for 3-5 days for maximal sporulation. The Aspergillus niger strains were screened for xylanase production by submerged fermentation. Xylanase activity was ranged from 30-225 U ml-1 and dry cell mass from 6.48-26.56 g L-1. Maximum xylanase productivity was obtained by GCBT-35 (225 U ml-1). The mycelial dry weight was 9.54 g L-1 while mycelia were small in size and rounded in shape.