Extraction and purification of biologically active metabolites from the Rhodococcus sp. MTM3W5.2

• Main Authors: Alenazi, Mohrah, kapadia, Jaimin, South, Patrick, Shilabin, Abbas, Lampson, Bert
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2018
• Subjects: Extractio; purification; biologically; active; metabolites; Organic Chemicals; Other Life Sciences; Other Microbiology
• Online Access: https://dc.etsu.edu/asrf/2018/schedule/71

Due to an increasing prevalence of bacterial resistance to antibiotic drugs and the overuse of commercial antibiotics, the need to discover novel antibacterial compounds is becoming more urgent. There is one promising avenue of novel drug discovery which has begun to be explored; the analysis of secondary metabolites. Rhodococcus is a genus of gram-positive bacterium known for their ability to catabolize a wide range of compounds, and more notably for its ability to produce bioactive secondary metabolites. Rhodococcus belongs to the class actinobacteria. A species of Rhodococcus, MTM3W5.2, has been discovered in Morristown, Tennessee and was found to produce a metabolite with inhibitory activity against closely related species. The aim of this study is to elucidate the structure of the inhibitory metabolite by first isolating and purifying it, and then characterizing it using spectroscopic techniques. The compound was isolated from MTM3W5.2 RM broth cultures using n-butanol extraction, which yielded an active crude extract. The crude extract was then subjected to fractionation using a Sephedex LH-20 column with a 100% methanol solvent. The inhibitory activity of the fractions was tested through disk diffusion assay using Rhodococcus erythropolis as an indicator of inhibitory activity. Further preparation was completed using preparative reverse-phase high-performance liquid chromatography. Advanced purification was conducted using multiple rounds of analytical reverse-phase HPLC and activity was tested at each subsequent step using disk diffusion assay. Throughout the study, the HPLC fractions were characterized and the stability was monitored using UV-Visible spectroscopy. Two pure samples at 58.63 and 72.72 minutes from HPLC (High-performance liquid chromatography) collections were selected for further structural identification and are currently being studied using spectroscopic techniques, most notably 2D NMR spectroscopy (two-dimensional nuclear magnetic resonance).