Isolation, identification, screening and optimisation of pectinase producing soil fungi (Aspergillus niger)

Abstract

Microbes are a well-known source for the production of extracellular enzymes and industrially important secondary metabolites. The present study demonstrates the isolation of pectinase producing microbes, screening and optimisation of pectinase production from soil born fungi. In order to examine pectinase production from microbes, the soil was collected from Porur vegetable market, Chennai, Tamil Nadu, India. Total of 40 fungal isolates were screened for the pectinase production using the selection medium and found three isolates reveals a pectinolytic zone of inhibition in agar plates around the colony. Among the three isolates, the best producer was chosen based on their pectinolytic activity (9mm zone of inhibition) for further molecular characterisation. The molecular characterisation study revealed that the selected fungi characterised as Aspergillus niger with 18s RNA of the organism. Further for the production of pectinase from Aspergillus niger the submerged fermentation (SmF) and solid state fermentation (SSF) are used with organic wastes such as wheat bran, rice bran, pomegranate peel and orange peel. Compared with the SmF and SSF the culture with SmF produces higher yields of pectinase (235.04 nkat) at 72 hrs (30°C) on supplemented with wheat bran (20%) and orange peel (10%) in the production medium. In the SmF sucrose (1%) was used as a carbon source and physiological pH 5.5 was maintained. The produced enzyme shows the Km value 1.0mg/ml and Vmax value found to be 500 nkat.