ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF ENDOPHYTIC FUNGI FROM COFFEE (Coffea arabicaL.) HUSK

Abstract

This study was intended to investigate the antioxidant and antimicrobial activities of endophytic fungi isolates from coffee husks. The coffee husk sample was collected from the local processor in Nensebo district, Arsi Zone, Ethiopia. The samples were surface sterilized before used as endophytic fungal culture. The nutrient value was prepared as per manufacturer instructions. Fungal culturing and identifications of genera were made according to fungal identification manual. Then, the crude endophytic fungal extracts were prepared using methanol as a solvent. The antioxidant activity was conducted based on determination of phenolic content, DPPH and hydrogen peroxide free radical scavenging activities. The antimicrobial activity test was conducted based on disc diffusion and broth dilution methods. The macroscopic colony appearances and microscopic hyphal structure of the fungal isolates from coffee husk identified were five isolates including Penicilliumsp, Aspergillusfumigatus, Chaetomiumsp and Fusarium sp. The antioxidant activities of the methanolic extract from the endophytic fungal isolates were found significantly the highest phenolic content (7.01%), DPPH (56.31%) recorded for Chaetomiumsp extract from coffee husk isolate. Fusariumsp extract from coffee husk isolate has recorded significantly the highest hydrogen peroxide scavenging activity, HPSA (61.69%). The highest concentration of the crude extracts (200 mg/L) presented the strongest antibacterial activity with maximum zone of inhibition (25.80 mm) for Fusariumsp extract against S. pyogenes. For the antifungal activity the maximum zone of inhibition 22.23 mm was recorded for Fusariumsp extract against A. versicolorsp whilst the minimum zone of inhibition diameter (11.50 mm) with the highest concentration of the extract (200mg/L) was recorded for Penicilliumsp extract against A.niger. The endophytic fungal extract presented the strongest antibacterial activity with MIC (1.56 mg/L) and corresponding MBC (1.56 mg/L) for Fusariumsp extract against S. pyogenes. The strongest antifungal activity with MIC (3.13 mg/L) and corresponding MFC (3.13 mg/L) was recorded for Fusariumsp against A. versicolor. In the present study, the Fusariumsp isolate extract was xvi found to have the best antioxidant and antimicrobial potential that can be recommended for microbial production of bioactive compounds if enriched through further investigation