Optimization of biodegradation of terephthalic acid (TPA) using Glutamicibacter mysorens ASR 14 and its application in treating TPA in sewage wastewater

The alarming use of polyethylene terephthalate (PET) for multiple applications, such as soft drink bottles, packaged boxes, and textiles, has caused significant concerns due to its accumulation in the environment. Terephthalic acid (TPA), the precursor of PET synthesis, is released during the slow breakdown by abiotic processes, making it a widespread pollutant. This study presents systematic optimization of TPA degradation using the one-factor-at-a-time (OFAT) method. The optimized media for degradation consisted of 0.1% (w/v) xylose, 0.1% (w/v) ammonium sulphate, 0.1% (v/v) Tween 60, pH-7.5, inoculum 4% (v/v), agitation at 150 rpm with 0.2% (12 mM) TPA. A nearly complete degradation (99.49%) of TPA was observed after 168 h. Kinetic study was performed for 7 days, monitoring six parameters: TPA concentration, esterase and protocatechuate 3,4-dioxygenase activity, total protein content and cell viability. Experimental degradation kinetics were fitted to four models that showed statistical significance of >95%. The degradation rate constant was 1.63 mM/day (0.27 g/L) with a calculated half-life of 3.42 days. Catechol and Protocatechuic acid (PCA) were identified as the major degradation products. The isolate was evaluated for its potential to treat wastewater containing TPA. Different sludge-to-wastewater ratios were tested for 6 days, showing their potential for biological wastewater treatment. This study demonstrates the potential of Glutamicibacter mysorens ASR 14 for bioremediation in wastewater treatment, targeting polymer-contaminated effluents. • G.mysorens ASR 14 achieved nearly complete TPA degradation (99.49%) in 168 h under optimized conditions • The study identified optimal parameters for degradation through the OFAT method • Catechol and Protocatechuic acid were identified as major degradation products with metabolic analysis channelling towards the TCA cycle and fatty acid synthesis • The bacterium removed TPA from real sewage wastewater, highlighting its potential for bioremediation