Optimization and isolation of bioactive natural products from sediment actinomycetes

• Main Author: Boo, Charlotte Ai-En
• Other Authors: Liang Zhao-Xun
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Science
• Online Access: http://hdl.handle.net/10356/72511
• Institution: Nanyang Technological University

Alarming numbers of microorganisms are gaining multi-drug resistance in hospital and community settings, thereby presenting urgency to combat this issue. This study aimed to discover and characterize bioactive secondary metabolites produced by 2 strains of actinomycetes namely P19 and SD50, which were derived from quarry and mangrove sources respectively. P19 strain was cultured in Pharmamedia and growth conditions were monitored with different flasks. SD50 was cultured on MS agar plates prior to the extraction. Analysis of P19 and SD50 ethyl acetate and acetone extracts using analytical High-Performance Liquid Chromatography (HPLC) and subsequent fractionation of extracts using semi-preparative HPLC successfully isolated compounds used for bioactivity assays. Strong bioactivities displaying more than 90% inhibition were found in P19 pure compound with broad-spectrum antibacterial properties; SD50 fraction C with antibacterial and antifungal properties and SD50 yellow compound D with antibacterial properties. Mass Spectrometry of P19 pure compound has revealed that it is a possible analogue of echinomycin and SD50 yellow compound D to belong to the same class of antibiotics as anthracycline or angucycline. Future research incorporating Nuclear Magnetic Resonance spectroscopy could identify these potentially novel compounds. Moreover, expression of encrypted metabolites in strains P19 and SD50 under different conditions could be attempted.