Title: Comparative study of endo-?-1,4-mannanases from novel bacterial strains for the production of galactomanno-oligosaccharides
Abstract:
Prebiotics are compounds including sugar polyols, polysaccharides and oligosaccharides, and resistant starches, and fibres which are non-digestible and should not absorbed by Gastro-Intestinal tract (GI tract). Galactomannan is a polysaccharide which is made of linear mannose chain and galactose is present as the side branch group. Though it has prebiotic potential, but its usage is limited because of it highly viscous nature. Galactomannan oligosaccharides (GMOs) are the emerging prebiotic which can be used to develop the functional foods for the benefit of human kind. In the presented work we performed a comparative analysis of endo-1,4- β-mannanase enzyme produced from novel bacterial strains. The bacterial strains were isolated form the soil samples taken from guar fields of Rajasthan and Haryana, India. The recombinant construct made by inserting gene into pET vectors using recombinant DNA technology. The enzyme was purified with Ni-NTA chromatography. The comparative analysis with biochemical characterization showed that all the enzymes were highly active in the pH 6, their optimal temperature are different but all showed more than 50% activity in the low as well as high temperature (30-90?C). The RJ 32 showed the optimum activity with 0.1U of enzyme/mg of substrate dosage in pH 6 at 55?C temperature, RJ 35 optimal activity was found at pH 6 and 50 ?C with 0.09U of enzyme/mg of substrate and HR 10 showed the optimal activity at pH 6 and 65 ?C with 0.08U of enzyme/mg of substrate. The endomannanase of the RJ 32 and RJ 35 showed thermal stability with 50% of enzymatic activity upto 7 days, and HR 10 upto 12hr. The enzymes were active at high temperatures even though they are not thermophilic strains, isolated from the mesophilic zone and highly stable for longer duration at their optimal temperature. These parameters increase their industrial application for the production of galactomanno-oligosaccharides.
