In this study, Fe₃O₄ was added to the anaerobic fermentation process of waste cooking oil (WCO) and aerobic sludge (AS), and its effects on the production of volatile fatty acids (VFAs) were explored from the perspectives of propionic acid concentration, Fe²⁺ concentration, and microorganisms. The results showed that when the dosage of Fe₃O₄ was 5 g/L, it was conducive to the hydrolysis and acidification of WCO. And it had a significant effect on the concentration of VFAs and propionic acid. The maximum concentration of VFAs was 7142.84 ± 201.48 mg COD/L, and the maximum concentration of propionic acid was 4990.92 ± 124.76 mg COD/L, which increased by 20.65 % and 27.65 % respectively compared with the blank group. Meanwhile, microbial community analysis showed that Firmicutes, Proteobacteria, and Bacteroidetes are the main phylum for the production of VFA in the anaerobic fermentation of WCO and as. Veillonellaceae under Firmicutes was the main microorganism to produce propionic acid. It provides microbial support for the hydrolysis of WCO and the subsequent production of propionic acid. This study provides a new idea for Fe₃O₄ to promote the hydrolysis of WCO and produce propionic acid, and brings potential economic benefits to WCO treatment.

本研究将Fe ₃ O ₄添加到地沟油（WCO）和好氧污泥（AS）的厌氧发酵过程中，从丙酸的角度探讨其对挥发性脂肪酸（VFAs）生产的影响。浓度、Fe ²⁺浓度和微生物。结果表明，当Fe ₃ O _4的用量为5 g/L，有利于WCO的水解酸化。并且对VFAs和丙酸的浓度有显着影响。VFAs最高浓度为7142.84±201.48 mg COD/L，丙酸最高浓度为4990.92±124.76 mg COD/L，较空白组分别增加20.65%和27.65%。同时，微生物群落分析表明，厚壁菌门、变形菌门和拟杆菌门是WCO和as厌氧发酵中产生VFA的主要门。厚壁菌门下的韦荣菌科是产生丙酸的主要微生物。它为 WCO 的水解和随后的丙酸生产提供微生物支持。本研究为Fe ₃ O ₄促进WCO水解生成丙酸提供了新思路，为WCO处理带来了潜在的经济效益。