<p>A novel salt-tolerant aerobic denitrifying bacterium, <i>Marinobacter</i> sp. strain B108, was isolated from a marine recirculating aquaculture system (MRAS). The optimal aerobic denitrification parameters were CH₃COONa as carbon source, pH of 8, C/N of 16, temperature of 35 °C, dissolved oxygen (DO) of 6 mg/L and salinity of 30. Under these optimal conditions, <i>Marinobacter</i> sp. strain B108 had a removal efficiency of 100% for NO<Stack> ₃ ⁻ </Stack>-N and 98.89% for total nitrogen (TN) within 24 h. The nitrate removal pathways of <i>Marinobacter</i> sp. strain B108 were included by the assimilative reduction pathway (NO<Stack> ₃ ⁻ </Stack>-N→biomass N) and the dissimilatory reduction pathway (NO<Stack> ₃ ⁻ </Stack>-N→N₂) of aerobic denitrification, and lack of dissimilatory reduction to ammonium pathway (NO<Stack> ₃ ⁻ </Stack>-N→NH<Stack> ₄ ⁺ </Stack>-N). The nitrogen removal process of <i>Marinobacter</i> sp. strain B108 was mainly contributed by the dissimilatory reduction pathway. The kinetic parameters for NO<Stack> ₃ ⁻ </Stack>-N and NO<Stack> ₂ ⁻ </Stack>-N removal were determined as <i>V</i>_m of 971.566 and 165.336 mg/(gDCW·L·h), and <i>K</i>_m of 22.74 and 31.68 mg/L, respectively. This work reflects the practical application potential of <i>Marinobacter</i> sp. strain B108 for nitrogen removal in MRAS.</p>