Abstract:To establish a green and efficient agar desulfation process，Priestia megaterium was cultured with Gracilaria plant as the sole sulfur source for agar desulfation.The growth of desulfating bacteria was taken as the evaluation index.A direct agar desulfation process using the Gracilaria plant was constructed，and the sterilization method，Gracilaria addition amount，and concentrations of various components in the culture medium for the desulfation process using the Gracilaria plant were optimized.The results showed that after the optimization of desulfation process，the desulfurization rate of agar from the Gracilaria plant reached 37.985%.The gel strength of the agar was increased from below the detection limit to（200.263±7.121）g/cm2，and the quality of the fermented agar was significantly improved.