Identification of a novel anti-ice-nucleating polysaccharide from Bacillus thuringiensis YY529

Strain YY529, capable of producing some anti-ice-nucleating materials (ANM), was isolated from the surface of a camphor leaf. Strain YY529 was identified as Bacillus thuringiensis from its characteristics and taxonomy; the optimum temperature and pH for producing these ANMs were 30 degrees C and 7.0, respectively. One of the ANM with the highest activities among them was purified from the culture. The molecular weight of the ANM was approximately 130 kDa based on a gel filtration analysis. We confirmed that this ANM was a polysaccharide based on the results of the treatment with a mannosidase and the molish reaction. In addition, the LCMS analysis showed that this anti-ice-nucleating polysaccharide (ANPS) had the polyacetyl-D-glucosamine moiety in its structure. Furthermore, this ANPS showed its ability as a non-freeze agent in a preservative solution for the cryopreservation of cock liver. This is the first report of ANPS as a novel ANM from Bacillus thuringiensis YY529.