LC/MS detection of oligogalacturonic acids obtained from tragacanth degradation by pectinase producing bacteria

Tragacanth, a highly branched carbohydrate polymer isolated from Astragalus, is one of the most commonly used gums in food industry. The primary structure of tragacanth is composed of galacturonic acid monomers connected with 1-4 links, and it is very similar to the pectin. Tragacanth degradation by microorganisms is significant in two aspects: first, food preservation and microbial growth control due to too much use of tragacanth in the food industry, second, therapeutic and pharmaceutical potential of obtained oligosaccharides. In the present study, we report three new strains of bacteria, Acinetobacter guillouiae strain TD1, Kosakonia sacchari strain TD2, and Bacillus vallismortis strain PD1 with the capability of growing in tragacanth as an only source of carbon and energy. The evolutionary history of the isolated strains was analyzed based on 16S rRNA gene sequences in MEGA7 using the neighbor-joining method. The production of di and tri galacturonic acid due to pectinase activities of the strains were detected by thin layer chromatography (TLC) and liquid chromatography/Mass spectroscopy (LC/MS) analysis. Here is the first report of the ability to grow in tragacanth and pectinase activity monitoring in bacteria. Our results revealed that all of the isolated strains are capable of degrading pectin and tragacanth to oligo-galacturonic acids. The obtained products, which have different structures depending on the tragacanth structures and types of pectinolytic enzymes, would show therapeutic and pharmaceutical potentials.