Biosorption of copper by nepenthes ampullaria-associated-endophytic fungi

In recent years, environmental pollution by heavy metals has caused increasing ecological damage and led to global public health concerns. Biosorption is one of the ways to deal with heavy metal pollution. In this study, endophytic fungi were (a) isolated from the carnivorous plant Nepenthes ampullaria (b) assessed for their resistance against heavy metal copper and (c) evaluated for their biosorption capacity. In total, 147 fungal isolates were isolated from Nepenthes ampullaria and only 11 (7.5%) of the total isolates were capable to resist copper concentration up to 1000 ppm. The 11 fungal isolates were identified through molecular method, and grouped as members of the Phomopsis, Diaporthe, Nigrospora, and Xylaria. The fungal isolate NA40 related to Xylaria sp. achieved the highest biosorption capacity of of 73.26 mg/g using live biomass, thus chosen for study of proteome expression in response to copper. Three different copper concentrations (0, 300, 500 ppm) were used in the study. Results show that there are 11 protein spots being up-regulated and 1 protein spot down-regulated in response to copper. The protein spots were identified to be related to the enzymes involved in heat shock protein, DNA repair and antioxidant reaction. This study on Xylaria serves as a baseline study for the response of the fungus to copper.