Enzymatic bioprospecting of endophytic Aspergillus niger isolated from Albizia lebbeck (L.) Benth

Abstract

Endophytic fungi reside inside plants in a mutualistic relationship with the host and produce numerous bioactive compounds, including extracellular enzymes. A rich diversity of endophytic fungi associated with the medicinal plant Albizia lebbeck (L.) Benth was bio-prospected in the present study. Thirty-three isolates obtained from the plant were assessed for secretion of six different extracellular hydrolytic enzymes. The results showed that 38%, 9%, 69%, 16%, 38%, and 13% of the endophytic isolates could produce amylase, protease, lipase, laccase, cellulase, and gelatinase enzymes, respectively. Overall, 78% of the isolates showed positive results for one or the other enzyme. Aspergillus niger (Isolate 8) isolated from the bark proved to be most efficient in producing all the enzymes and was further exploited for various applications. The crude fungal amylase of the isolate helped in 39.08% reduction in biochemical oxidation demand (BOD) of municipal wastewater. Effective blood stain removal from the white cotton cloth was achieved when crude protease was used in combination with detergent. 13.29% biodegradation of vegetable oil was observed using fungal lipase. Dye decolorization of methylene blue (71.65%) and methyl orange (56.53%) was observed by fungal laccase. Saccharification of bagasse (83.94%) and paper (64.93%) was achieved by using fungal cellulase. Complete extraction of silver from waste X-ray films was achieved by crude gelatinase. The results obtained in the present study can further be strengthened using purified enzymes.