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A Gram-stain-negative, rod-shaped bacterial strain, JN53 T , was isolated from the surfaces of weathered rock (potassic trachyte) from Nanjing, Jiangsu Province, PR China. Strain JN53 T grew optimally at 30 6C, pH 7.0. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JN53 T belonged to the genus Chitinophaga in the family Chitinophagaceae. It was most closely related to Chitinophaga terrae KP01 T (97.3 % 16S rRNA gene sequence similarity), Chitinophaga eiseniae YC6729 T (96.3 %). Strain JN53 T contained MK-7 as the major menaquinone and homospermidine as the major polyamine. The main fatty acids of strain JN53 T were iso-C 15 : 0 , C 16 : 1 v5c, C 16 : 1 v7c and/or C 16 : 1 v6c (summed feature 3), iso-C 17 : 0 3-OH, C 16 : 0 , iso-C 15 : 0 3-OH and C 16 : 0 3-OH. The polar lipid profile contained phosphatidylethanolamine, unknown aminolipids and unknown lipids. The total DNA G+C content of strain JN53 T was 49.7 mol%. The low level of DNA-DNA relatedness to other species of the genus Chitinophaga and the many phenotypic properties that distinguished strain JN53 T from recognized species of this genus demonstrated that isolate JN53 T should be classified as representing a novel species of the genus Chitinophaga, for which the name Chitinophaga jiangningensis sp. nov. is proposed. The type strain is JN53 T (5CCTCC AB 2013166 T 5JCM 19354 T ).

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Bacteria play important roles in mineral weathering and soil formation. However, little is known about the nutrition-related changes in mineral weathering potential and pattern of bacteria. In this study, mineral weathering behaviors of a novel mineral-weathering bacterium Chitinophaga jiangningensis JN53 were characterized in the presence of three contrasting biotite or potassium feldspar-added media. C. jiangningensis JN53 increased more Fe release from the minerals in the M-BHm (nutrition-poor medium) than in the SSKM (nutrition-rich medium) and BHm (nutrition-moderate medium), while C. jiangningensis JN53 released more Al from the minerals and Si from biotite in the SSKM. Similar Si release from potassium feldspar by C. jiangningensis JN53 was observed in the SSKM, BHm, and M-BHm. K releasing ability of C. jiangningensis JN53 was significantly higher in the biotite-added M-BHm. Highest and lowest growth of C. jiangningensis JN53 was observed in the SSKM and M-BHm, respectively. In the presence of the minerals, C. jiangningensis JN53 mainly produced gluconic acid in the SSKM and acetic acid in the BHm and M-BHm. C. jiangningensis JN53 also produced large amount of succinic acid in the biotite-added SSKM and oxalic acid in the potassium feldspar-added M-BHm. The results showed the growth, production of organic acids, and mineral weathering ability of C. jiangningensis JN53 in the three contrasting nutrition conditions. The results also suggested the change in the mineral weathering behaviors of C. jiangningensis JN53 under different levels of nutrition conditions.