Enhancement of microorganisms by MgAl-LDO@zeolite composites to buffer the impact of hydraulic loading and maintain physiological activity

The water quality of effluents from decentralized aquaculture exhibits substantial fluctuations and considerable variability, while the shock loads of pollutants significantly affects the physiological activity of microorganisms in biological treatment systems. In this study, the performance of microorganisms in response to fluctuations in nitrogen and phosphorus concentrations was enhanced by loading layered bimetallic oxides onto a zeolite surface to form MgAl-LDO@zeolite, which was then immobilized with microorganisms in alginate beads. A Box–Behnken design was used to optimize the parameters of the material synthesis process. MgAl-LDO@zeolite immobilization enhanced the microbial removal of ammonium nitrogen ( N H 4 + − N ) and total phosphorus by 11.43 % and 20.66 %, respectively. Analyses of the malondialdehyde levels and extracellular polymeric substances in the various biological systems further indicated that the composites helped reduce oxidative stress and maintain normal microbial physiological activity. Three-dimensional fluorescence spectroscopy revealed that MgAl-LDO@zeolite immobilization promoted tryptophan-like protein production by the microorganisms and enhanced their metabolic interactions. Overall, the MgAl-LDO@zeolite composites were significant in mitigating environmental loading shocks and maintaining microbial metabolic activities and pollutant removal efficiency. Our study provides new ideas for the application of composites in water treatment technologies. • MgAl-LDO@zeolite was prepared and immobilised with microorganisms via alginate . • Response surface, adsorption kinetics and isotherm characterisation were used to analyse the material. • MgAl-LDO@zeolite mitigates hydraulic loading impact and boosts microbial stress resistance. • MgAl-LDO@zeolite sustains microbial activity and strengthens metabolic linkages. • MgAl-LDO@zeolite enhances the co-operation of bacteria associated with nitrification and denitrification.