Brachybacterium netajii sp. nov.: A halotolerant bacterium capable of p-Nitrophenol degradation, isolated from the Ganges river, West Bengal, India

Cells are Gram-positive and non-motile. Colonies formed on PNP agar are yellowish-white and circular. Growth occurs over a temperature range of 20–40°C, with optimal growth observed at 30 °C. The strain tolerates up to 9% NaCl and grows well within a pH range of 5.8–8.0. The strain is oxidase-negative but catalase-positive and exhibits starch-hydrolyzing activity. Positive reactions was observed for β-glucosidase activity. The organism is capable of utilizing sucrose, D-xylose, D-glucose, D-mannose, L-arabinose, D-melibiose, D-maltose, D-trehalose, D-cellobiose, D-sorbitol, and D-mannitol as carbon sources. Positive reactions are recorded for adenosine assimilation, L-lactate utilization, and citrulline metabolism. In contrast, the strain tested negative for Ala-Phe-Pro arylamidase, glycine arylamidase, pyrrolidonyl arylamidase, proline arylamidase, β-alanine arylamidase, and Gly-Gly arylamidase. H2S production was not detected. Furthermore, the strain lacked enzymatic activities associated with β-N-acetylglucosaminidase, lipase, phosphatase, β-glucuronidase, α-galactosidase, α-glucosidase, β-galactosidase, and β-xylosidase. The strain failed to utilize D-tagatose, 5-keto-D-gluconate, succinate, palatinose, N-acetyl-D-glucosamine, L-malate, L-arabinitol, and L-lactate as substrates.

The cellular fatty acid profile is dominated by C15:0 Anteiso (24.61%) as the most abundant, followed by C₁₁:₀ (21.06%), iso-C₁₆:₀ (11.89%), C₁₆:₀ (11.58%), and anteiso-C₁₇:₀ (11.24%). The predominant respiratory quinone is menaquinone MK-7, consistent with members of the genus Brachybacterium. The reference strain, designated DNPG3 (= MTCC 13125), was isolated from the River Ganges, W.B, India.