Biodegradation of tetracycline using hybrid material (UCPs-TiO2) coupled with biofilms under visible light

To develop a more green and effective method for tetracycline (TC) removal, a hybrid material (conversion phosphors-TiO 2 , UCPs-TiO 2 ) was coupled with a biofilm to achieve enhanced removal of TC. The removal of TC by biofilm coupled with UCPs-TiO 2 under visible light reached 82%, which was 35% higher than that in treatment using only the biofilm. Extracellular polymeric substance (EPS) promoted the production of hydroxyl radicals by UCPs-TiO 2 , as the EPS acted as an electron transfer medium and accelerated the TC mineralization. Biofilm in the coupled system tolerated TC stress by regulating its antibiotic resistance genes (ARG) and superoxide   dismutase (SOD), and allowed it to maintain stable and efficient removal of TC. This study documents a method to couple a hybrid material with microbial aggregates, creating a promising system for removing refractory organics, such as TC, from water. The study also offers insight into the mechanisms underlying TC removal by microbial aggregates combined with new functional materials.