Following pretreatments A, B, C and D, the tubes were centrifuged
at 3000g for 10 min. The pretreatment supernatant was
collected for inhibitor detection with a high pressure liquid chromatograph
(HPLC, Shimadzu LC-20AD). The pretreated RWSS was washed five times with 20 mL distilled water and dried at 80C for
further analysis.