Plant mangrove-associated fungus Culvularia lunata and a simple and efficient method of obtaining high yield of pure mannitol from the same

Abstract

The present invention relates to a plant mangrove-associated fungus Culvularia lunata of International deposition no. ______, and a simple and efficient method of obtaining high yield of pure mannitol from a plant mangrove-associated fungus Curvularia lunata, said method comprising steps of cutting the leaves into small pieces and placing it on potato dextrose agar (PDA) plates for 48 hours, maintaining the culture at temperature ranging between 26-47° C. and salinity ranging between 4-32 ppt with occasional stress conditions for about 17-19 days to obtain mycelial mat, sonicating the mat to lyse the cells, extracting crude from the sonicated mat using methanol repeatedly, concentrating the crude, treating the concentrated crude extract with solvents of increasing polarity, obtaining aqueous fraction as white powder residue after the treatment containing crude mannitol, purifying the crude mannitol by chromatography to obtain pure mannitol with about 75% of the total crude extract.

Description

FIELD OF THE PRESENT INVENTION[0001] The present invention relates to a plant mangrove-associated fungus Culvularia lunata of International deposition no. ______, and a simple and efficient method of obtaining high yield of pure mannitol from a plant mangrove-associated fungus Curvularia lunata, said method comprising steps of cutting the leaves into small pieces and placing it on potato dextrose agar (PDA) plates for 48 hours, maintaining the culture at temperature ranging between 26-47.degree. C. and salinity ranging between 4-32 ppt with occasional stress conditions for about 17-19 days to obtain mycelial mat, sonicating the mat to lyse the cells, extracting crude from the sonicated mat using methanol repeatedly, concentrating the crude, treating the concentrated crude extract with solvents of increasing polarity, obtaining aqueous fraction as white powder residue after the treatment containing crude mannitol, purifying the crude mannitol by chromatography to obtain pure mannitol...

AI Technical Summary

Benefits of technology

[0117] 1. This is a novel source for mannitol.[0118] 2. It is a common fungus (found associated with mangrove leaves of Acanthus illicifolius, collected from Goa coast).[0119] 3. Easy to isolate and culture.[0120] 4. The fermentation medium used for optimum yield is of low cost.[0121] 5. The fermentation conditions are feasible and can be easily carried out in the laboratory.[0122] 6. The secondary metabolites can be easily separated from the main compound.[0123] 7. Can be preserved using standard techniques and revived as and when required.[0124] 8. The extraction process of mannitol from fungal mat and purification of the same involves simple techniques as compared to the commercial preparation of mannitol.[0125] 9. We used room temperature and pressure and no catalyst is used for the production of mannitol. Commercially, mannitol is still produced by the catalytic hydrogenation of a 50:50 fructose:glucose mixture which uses hydrogen at high temperature and pressure with Raney Nickel as a catalyst.[0126] 10. We produced good yield of mannitol (70% of crude extract) without any other polyol contamination. Commercially, hydrogenation of fructose syrups or invert sugar resulted in the coproduction of another sugar alcohol, sorbitol and the yield of mannitol is only 25%.[0127] 11. In the present invention, the crude mannitol was chromatographed using G-10 as solid support, using methanol:water (95:5) as eluent for final purification. On the other hand, the purification steps in the commercial production of mannitol are tedious.

Problems solved by technology

The disadvantage of this method is that the composition of the hydrogenated mixture consists of only about 25% mannitol and the remaining 75% was sorbitol.

This production procedure makes the manufacture cost for mannitol relatively high.

The prior art biotechnical process for the conversion of sugar to mannitol has not proven entirely satisfactory, as they do not provide an adequate conversion yield and therefore the industrial production is still based on hydrogenation.

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