Xanthomonas chitinilytica sp. nov., a novel chitinolytic bacterium isolated from a microbial fermentation bed material.

A Gram-stain-negative bacterium, H13-6, was isolated from a microbial fermentation bed material collected from a pig farm located in Yan'an, Shaanxi, China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain H13-6 was affiliated with the genus Xanthomonas and showed highest similarity to strain Xanthomonas maliensis M97 (98.38%), Xanthomonas prunicola CFBP 8353 (98.26%) and Xanthomonas oryzae ATCC 35933 (98.11%). The pairwise ortho Average Nucleotide Identity values and the digital DNA-DNA hybridization values between strain H13-6 and the other Xanthomonas species were all below their respective cut-offs. Two genes encoding for chitinase were found and the strain showed a strong chitin-degrading activity. The major fatty acids were Iso-C (55.9%), Antesio-C (7.4%) and Iso-C (5.5%) and the major polar lipids were diphosphatidylglycerol, phosphatidyglycerol and phosphatidylethanolamine. Based on the phenotypic properties and phylogenetic distinctiveness, Xanthomonas chitinilytica was proposed as a novel species of the genus Xanthomonas, with strain H13-6 (= CGMCC 1.61317 = NBRC 115641) as type strain.