Fructobacillus trapaeoli - A fructophilic lactic acid bacteria isolated from Manilkara zapota

Abstract

The study was undertaken to isolate and characterize fructophilic lactic acid bacteria from the fruit Manilkara zapota (chikoo). Microscopic, phenotypic, biochemical and molecular characterisation of the isolates was done. The Gram-positive thin rods (5 μm length and 0.25 μm thickness) were catalase and oxidase negative and did not hydrolyze arginine. The carbohydrate fermentation studies showed that the isolate preferred fructose similar to glucose as an energy source. The isolate had an optimum growth at 37ºC and also had grown at 45ºC. 16S rRNA sequencing confirmed the isolate as Fructobacillus tropaeoli DMM03 (NCBI accession number MT158673). There are very few reports of isolation and characterization of Fructobacillus from India. The osmotolerant nature of the isolate was established by its ability to grow in pH 5, 8 per cent NaCl, 35 per cent D-Fructose and 50 per cent D-Glucose. The isolate had also shown growth in the presence of heavy metals with a maximum concentration of 60 ppm cadmium and 2425 ppm lead. An autoaggregation of 46.3 per cent and cell surface hydrophobicity value of 22 per cent with apolar solvent xylene suggested the high adhesion potential. The isolate was found to be non-haemolytic and not liquefying gelatin which implies its safety in use for product preparation. The results point out a prospective area for future research in Fructobacillus tropaeoli DMM03 for tapping its potential in the field of probiotics and bioremediation.

Keywords

• fructobacillus
• lactic acid bacteria
• manilkara zapota
• osmotolerant