Abstract:Lacticaseibacillus paracasei subsp.tolerans GX0002948 isolated and identified from traditional sour porridge in Fusui County，Chongzuo City，Guangxi Zhuang Autonomous Region was used for fermentation of rice.With pH value as the core indicator，the fermentation process of sour porridge was optimized by Plackett-Burman design and response surface methodology on the basis of single-factor experiments.The optimal fermentation conditions of L.paracasei subsp.tolerans GX0002948 were determined as follows： inoculum size of 12.5%，glucose content of 5%，rice sterilization time of 7 min，fermentation temperature of 37 ℃，and fermentation time of 90 h.Under these optimized conditions，fermented sour porridge reached pH 2.70±0.03 and the titratable acidity of （8.77±0.15） °T，which represented a decrease of 2.24 and an increase of 7.44 °T compared with naturally fermented sour porridge.