Screening of potential xylanase producing fungal strains under solid state fermentation condition
Deepsikha Anand, Sangeeta Yadav, Dinesh Yadav
Xylanases are industrially important group of hydrolytic enzymes associated with the cleavage of β-1,4 backbone of the complex plant cell wall polysaccharide xylan. Several microbial sources namely bacteria, actinomycetes and fungi have been reported to be important sources of xylanases. In the present study, a total of 40 fungal strains were screened to assess the potential for the production of xylanases under solid state fermentation (SSF) conditions. Xylanase from three of the promising strains namely Aspergillus tubingensis MTCC1781, Oidiodendron echinulatum MTCC1356 and Aspergillus flavus MTCC10938 were further characterized for pH optima, pH stability, temperature optima, temperature stability and effect of metal ions. The pH optima observed for xylanase from Aspergillus tubingensis, Oidiodendron echinulatum and Aspergillus flavus was found to be 9.0, 7.0 and 9.0 respectively while pH stability ranged from pH 3.0-9.0. The temperature optima was 40°C, 60°Cand 50°C for xylanase from Aspergillus tubingensis, Oidiodendron echinulatum and Aspergillus flavus respectively while temperature stability was observed in the range of 20oC- 60oC, 10oC-60oC and 10oC-50oC respectively. Among the different metal ions tested, Cu+2and Mn+2showed slight enhancement in enzyme activity while Hg+2 inhibited the xylanase activity.