Isolation, identification and Screening of Xylanase producing fungi from Apple (Pyrus malus L.)

Abstract

The objective of the present investigation was to isolate the fruit spoilage fungi from Apple (Pyrus malus L.) sold in twin cities of Hyderabad and to identify the strains that secrete maximum amount of xylanase. Recently xylanases have been explained for their use in many processing industries such as paper, pulp, food and textile industries etc. In all 12 fruit spoilage fungi were isolated, identified and screened based upon the formation of clearing zones on malt extract agar medium (MEA) enriched with xylan as the sole source of carbon. The fungal isolates were also tested for their potential to deteriorate the fruit by satisfying Koch’s postulates (Pathogenicity test). Submerged fermentation was also carried out with the fungal isolates to identify the strain that could produce highest amount of xylanase at pH 6 and at temperature 28 ± 2°C. On screening, all the isolates could produce xylanase. However, the amount of enzyme production varied with the fungi. Growth was determined in terms of mycelial dry weight and soluble protein content was also determined which ranged between 90 to 200μg/ml. The pH change after the stipulated incubation period ranged from 5.5 to 7.0.