Ammonia water

Sugarcane bagasse was obtained from Guangxi Baiguitang Food Science and Technology Co., Ltd. (Guigang, China) and passed through the 80-mesh screen to obtain the powder for further use. Sodium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia water were from Damao Chemical Reagent Factory (Tianjin, China); xylanase was sourced from Sigma-Aldrich (San Francisco, USA); Candida tropicalis 31949 was purchased from China Industrial Microbiology collection management center (Beijing, China). All reagents were of analytical grade unless otherwise mentioned.

Beer yeast sludge (containing Saccharomyces cerevisiae) was collected after the fermentation process in Wuchuan Yanjing brewery and further purification or modification, were finished in the laboratory. Real petrochemical wastewater samples were collected from the discharged sewage of Maoming Petrochemical Refining Co., Ltd (Guangdong, China). The other chemicals in this study were consumed as provided by suppliers without any further modifications. Formaldehyde, anhydrous ethanol, polyethylene glycol (molar mass: 600), K₂Cr₂O₇, 1,5-diphenyl carbazide, FeCl₃·6H₂O and FeCl₂·4H₂O were purchased from Shanghai McLean Biochemical Technology Co., Ltd. (Shanghai, China). Hydrochloric acid, sulfuric acid, sodium hydroxide and ammonia water were provided by Tianjin Damao Chemical Reagent Co., Ltd. (Tianjin, China).