Actinobacteria Secondary Metabolites as a Potential Antimicrobial Agents
Actinobacteria are Gram positive organisms that have a high GC content in their genome. Bacteria in this phylum are capable of producing spores and even antimicrobial agents. Also, these microorganisms can help degrade various polysaccharides such as chitin, lignocellulose, cellulose. Some actinobacteria can live in symbiosis with termites, which can help decompose matter and can also provide protection to the termites inhibiting growth of entomopathogenic fungi. Previous studies have determined Actinobacteria inhibit growth of entomopathogenic fungi such as Beauveria bassiana and Metarhizium anisopliae. The objective of this study is to determine secondary metabolites and/or extracellular enzymes that can act as antimicrobial agents isolated from different Actinobacteria associated with termites in Puerto Rico (workers and soldiers). Actinobacteria were isolated by drowning the termites in phosphate buffer and beating them afterwards. The extract was inoculated in Chitin Agar, since Actinobacteria can use it as a carbon source. After isolating the bacteria, a sub-cultivation on Malt extract agar (MEA) was performed for extraction of secondary metabolites. A solid-liquid extraction was performed using organic solvents (ethyl acetate and methanol). The ethyl acetate extract was preliminary subjected to chemical tests in order to identify functional groups. 1H-, 13C-, and 31P- Nuclear Magnetic Resonances (NMR) experiments shown the presence of aldehydes, carboxylic acids, esters, and amides carbonyl groups, in addition to aromatic systems. 13C-NMR showed evidence of the presence of phosphorus atoms in the crude extract, which was later confirmed by 31P-NMR. High Performance Liquid Chromatography (HPLC) coupled to tandem Mass spectrometry (MS) it is in process and will further provide a metabolomic analysis of the crude extract.