A bacterial strain, designated Nsw-4(T), was isolated from a water sample of Niao-Song Wetland Park in Taiwan and was characterized by using a polyphasic taxonomic approach. Strain Nsw-4(T) was Gram-negative, aerobic, ivory-coloured, rod-shaped and motile by means of a polar flagellum. Growth occurred at 15-37 degrees C, pH 6.0-8.0 and 0-2 % NaCl. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain belonged to the genus Deefgea and that its closest neighbour was Deefgea rivuli WB 3.4-79(T) (96.9 %). The results of physiological and biochemical tests allowed the clear phenotypic differentiation of this isolate from D. rivuli WB 3.4-79(T). The major fatty acids were C16 : 1omega7c and C16 : 0. The G+C content of the genomic DNA was 53.7 mol%. On the basis of 16S rRNA gene sequence analysis and the chemotaxonomic and physiological data, strain Nsw-4(T) should be classified as representing a novel species and the second member of the genus Deefgea, for which the name Deefgea chitinilytica sp. nov. is proposed. The type strain is Nsw-4(T) (=BCRC 17934(T)=LMG 24817(T)).