I don't think polysaccharides should smell bad. Did they smell bad at first? If not, then they have probably been contaminated by bacteria. Maybe include some sodium azide, antibacterials or filter sterilize them next time, whichever is most appropriate for your application.

Thanks Jarrod King, The polysaccharides were good at first and there was no bad smell. After somedays i noticed that smell came..

Is there any problem with the sample for studing biological properties..?

I dont think that polysaccrides give foul smell. It may be bacterial or fungal contaminated.

Thank you Robin, If they are contaminated with bacteria or fungus can i continue with the biological assay..?

Continue go ahead. Check purity on TLC then proceed...

If they smell bad, the bacteria or fungi have probably degraded the polysaccharides. Like Robin says, check purity somehow.

A bad smell indicates a possible bacterial contamination which also indicates that your polysaccaride isolates are already denatured. It is not therefore advisable to use isolates with with that characteristic. On the safer side, you should keep your samples below 4 degrees

Thanks Dennis

Yea. its contaminated, because they are polysaccharides they will be easily contaminated. I think you need to store them -20 or -80 after precipitation. it depends what you want to do with them now, you will have some polysaccharides introduced from the micro-organism.