دانلود رایگان مقاله تولید اگزوپلی ساکارید توسط باکتری گرمادوست رودوترموس مارینوس

ABSTRACT

The thermophile Rhodothermus marinus produces extracellular polysaccharides (EPSs) that forms a distinct cellular capsule. Here, the first data on EPS production in strains DSM4252T andMAT493 are reported and compared. Cultures of both strains, supplemented with either glucose, sucrose, lactose or maltose showed that the EPS were produced both in the exponential and stationary growth phase and that production in the exponential phase was boosted by maltose supplementation, while stationary phase production was boosted by lactose. The latter was higher, resulting in 8.8 (DSM4252T) and 13.7 mg EPS/g cell dry weight (MAT493) in cultures in marine broth supplemented with 10 g/L lactose. The EPSs were heteropolymeric with an average molecular weight of 8 × 104 Da and different monosaccharides, including arabinose and xylose. FT-IR spectroscopy revealed presence of hydroxyl, carboxyl, N-acetyl, amine, and sulfate ester groups, showing that R. marinus produces unusual sulfated EPS with high arabinose and xylose content.

4. Conclusion

In conclusion, both R.marinus DSM 4252T and R.marinus MAT 493 produced exopolysaccharides. Different nutritional conditions influenced the production of the EPSs. The highest EPS production efficiency was however for both strains found in marine broth supplemented by lactose followed by a maltose supplemented marine broth. Monosaccharide analysis showed thatthe produced EPSs are heteropolysaccharides mainly consisting of xylose and arabinose. The FT-IR spectrum of the EPSs showed the presence of sulfate and carboxyl groups which demonstrated that they contain uronic acids. It also revealed the presence of amino sugars together with acetyl group. The unusual functional groups and monosaccharide composition makes the EPS of R. marinus interesting for further studies, motivating more detailed analysis of its chemical structure and such studies are in progress.