A mutant strain (PM1-33) with accelerated para-nitrophenol (PNP) degradation was obtained by mutagenizing WBC-3. Comparative proteomic analysis of WBC-3 and PM1-33 was performed to compare their differentially expressed proteins at 0 h, 3 h, and 7 h to investigate the reasons for the faster degradation of PNP by PM1-33 compared to WBC-3.