Characterization and  kinetic study of Ibuprofen Biodegradation by native bacterial Citrobacter strains PPYI-2 and YPI-2

Abstract Ibuprofen (IBU) is the third most used drug in the world.This enters our water system due to human excretion discharge. Thus, it attracts the attention of environmentalists for their environmental fate and degradation behavior. In the present study, the two IBU degrading Citrobacter freundii strain PYI-2 (MT039504) and Citrobacter portucalensis strain YPI-2 (MN744335) was isolated using enrichment culture technique, identified, and characterized from industrial wastewater samples. Their physiological and batch culture degradation studies have indicated that these strains involved in IBU degradation and their intermediates produced during were analyzed. These strains degrade IBU in the batch culture. The Design Expert® software suggested the optimum pH conditions for the growth of PYI2 and YPI2 were 6.9 and 5.8 and the optimum temperatures were, 42°C and 32°C, respectively. This was also seen during experimental study. After degradation, the GC-MS analysis of the chromatogram peaks indicated that hydroxyibuprofen, 2- (4-hydroxyphenyl-) propionic acid, 1,4-hydroquinone, and 2-hydroxy-1,4-quinol intermediate compounds were identified, with the retention time of 14.987, 15.654, 11.765, and 10.827, respectively. Finally, on the basis of analysis of GC-MS data, the metabolic pathway for degradation was predicted by Pathpred (online tool), and other research data available for the degradation of IBU. Therefore, these strains have shown the potential for the degradation of IBU and they can be deployed for further use in the bioremediation program.