Use of chitosan for chromium removal from exhausted tanning baths.

A novel approach, based on chitosan heavy-metal sequestrating ability, is proposed for chromium(III) removal from spent tanning liquor. Experimental results, obtained at lab-scale using real wastewater, are presented and discussed. Resulting efficiencies are extremely high, and strongly dependent on chitosan dose and pH value.

O-Specific chain structure from the lipopolysaccharide fraction of Pseudomonas reactans: a pathogen of the cultivated mushrooms.

An O-specific polysaccharide containing 2-acetamidino-2-deoxy-beta-D-glucopyranose (Glcp2Am), 2,4-diacetamido-2,4,6-trideoxy-beta-D-glucopyranose (QuipNAc4NAc, bacillosamine) and 2,4-di-(N-acetyl-L-alanylamino)-2,4,6-trideoxy-beta-D-glucopyranose (QuipNAlaAc4NAlaAc) was isolated from the phenol-soluble lipopolysaccharide fraction of the mushroom-associated bacterium Pseudomonas reactans. The structure, determined by means of chemical analysis and 1D and 2D NMR spectroscopy, showed a linear trisaccharide-repeating unit, as shown below:-->3)-beta-D-QuipNAlaAc4NAlaAc-(1-->3)-alpha-D-Glcp2Am-(1-->3)-alpha-D-QuipNAc4NAc(1-->To our knowledge, this is the first complete O-chain structure reported for the lipopolysaccharide of a mushroom-associated bacterium.