Immobilization and Denitrification Kinetics of Marinobacter sp. strain B108

Immobilized aerobic denitrifying bacteria (Marinobacter sp. strain B108) can solve the problem of bacterial retention and improve the nitrate removal efficiency under aerobic environment, thus removing nitrate from marine recirculating aquaculture systems (MRAS) economically and efficiently. Polyvinyl alcohol (PVA), sodium alginate (SA) and tea residue powder were used as support materials to immobilize Marinobacter sp. strain B108. The ratios of immobilized materials were explored and optimized, and the physicochemical characteristics and denitrification kinetics of immobilized aerobic denitrifying bacterial pellets were further investigated on the basis of the optimal immobilized materials ratio. The optimum ratios of support materials were 10.103% PVA, 1.548% SA, and 0.732% tea residue powder. Under the optimum conditions, the immobilized bacterial pellets had high mechanical strength and strong resistance to mechanical shear, and the removal efficiency of NO₃^--N within 7 h was 98.63% as initial influent NO₃^--N concentration was 100 mg/L. The kinetic process of NO₃^--N removal could be fitted by Monod model, and the V_max and K_m were 5.041 mg/(L·g·h) and 24.810 mg/L, respectively. The kinetic process of NO₂^--N removal could be fitted by Andrews model, and the V_max, K_m and K_i were 0.790 mg/(L·g·h), 23.783 mg/L, and 0.092 mg/L, respectively. The conclusions could lay a good foundation for aerobic denitrifying bacteria practical application in MRAS for nitrate removal treatment.