Involved in the degradation of para-nitrophenol (PNP). Catalyzes the reduction of p-benzoquinone to hydroquinone. 1,4-benzoquinone + H(+) + NADPH = hydroquinone + NADP(+) Binds 1 FMN per monomer. Xenobiotic degradation; 4-nitrophenol degradation. Homodimer. Cells lacking this gene are not completely unable to grow on PNP. Belongs to the WrbA family.