Isolation and Exploitation of Selected Endophytic Mycoflora from Terminalia arjuna for their Production of Extracellular Enzymes

Abstract

Endophytic fungi are those which are capable of thriving and surviving inside plant tissues without causing apparent harm to their host. They can be found in different plant parts including leaves, stems, bark, roots, fruits, flowers and seeds. These fungal groups form symbiotic and mutualistic associations with the plants providing various benefits for them while fungi receive nutrients and shelter from the plant. Terminalia arjuna (Roxb. Ex DC.) Wight & Arn., commonly known as ‘Arjun tree’ is an important medicinal plant specifically used in traditional medicine in Sri Lanka. The isolation and exploitation of endophytic mycoflora from T. arjuna is of significant importance because these microorganisms serve as a hidden, renewable source of novel bioactive molecules and industrially relevant extracellular enzymes.  This study focused on the morphological characterization of endophytic fungi isolated from leaves and roots of T. Arjuna followed by determining their enzyme activities. Samples were collected from the central province of Sri Lanka and twelve fungal isolates were selected to conduct morphological characterization and enzyme assays. All isolates, with the exception of one fungal strain, exhibited at least one enzymatic activity. The majority of the isolates were positive for the enzymes laccase and lipase. Out of the 12 isolates, nine isolates were positive for lipase enzyme production while eight isolates produced laccase enzyme. Four isolates were capable of solubilizing phosphate. One isolate was positive for all enzyme activities as well as phosphate solubilization activity. Several species were identified as Aspergillus sp., Rhizopus sp., Penicillium sp. and Alternaria sp. based on microscopic observations of their vegetative and reproductive structures.