Abstract: Antibiotics are difficult to degrade under low temperature in cold regions of northern China. To improve the adaptability of low-temperature degrading bacteria to the environment with low temperature and enhance recycling rate and removal effect on pollutants, enrofloxacin (ENR), a common antibiotic in the environment, was taken as the target pollutant. A low-temperature resistant immobilized bactericide was prepared using the developed process. We examined the adaptability of this immobilized bactericide to environmental conditions and its degradation ability on ENR. The results showed that: (1) The mechanical strength of the immobilized particles was increased by the addition of low-temperature resistant materials. The highest value of the mechanical strength was 113.7 N, being 256.7 times that of the conventional sodium alginate particles. (2) The immobilized bactericide weakened the influence of low temperature. The removal rate of ENR was significantly improved even at 4 and 8 ℃, with the removal rate being 11.6% and 11.9% higher than that of free-living bacteria. (3) The immobilized bactericide has a stronger adaptability to pH, and can achieve better degradation effect in slightly alkaline and acidic environments. At pH=8.0, the removal rate of ENR by immobilized bacteria was 22.9% higher than that by free-living bacteria. The immobilized bactericides further improved the adaptability and function of cryogenic bacteria to the low temperature. Our results could provide a reference for the efficient degradation of antibiotics under low temperature conditions in the northern region of China.

Key words: immobilization, enrofloxacin, psychrophile, biodegradation