Abstract: The optimization of culture temperature, initial medium pH, and carbon and nitrogen sources for improved production of extracellular polysaccharides by Lactobacillus plantarum XN1904E was carried out using one-factor-at-a-time (OFAT) and orthogonal array design methods. The results showed that the optimal culture conditions were determined as follows: initial pH 6.5, temperature 37 ℃, galactose as the best carbon source, and fish peptone as the best nitrogen source. Under these conditions, the production of extracellular polysaccharide was 235.41 mg/L. The polysaccharide at 0.2 mg/mL had antioxidant activity in terms of scavenging rate (27.54%) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.

Key words: Lactobacillus plantarum XN1904E, exopolysaccharide, culture conditions, optimization, antioxidant capacity

摘要： 为提高植物乳杆菌XN1904E胞外多糖产量，考察培养温度、培养基初始pH值、碳源和氮源对植物乳杆菌XN1904E胞外多糖产量的影响。通过单因素试验和正交试验确定植物乳杆菌XN1904E产胞外多糖的最佳培养条件。结果表明：最佳培养条件为培养基初始pH 6.5、培养温度37 ℃、半乳糖为最适碳源、鱼蛋白胨为最适氮源，此条件下验证实验结果表明，植物乳杆菌XN1904E胞外多糖产量为235.41 mg/L；植物乳杆菌XN1904E胞外多糖水溶液（0.2 mg/mL）对1,1-二苯基-2-三硝基苯肼自由基的清除率为27.54%，表明其具有一定的抗氧化能力。

关键词: 植物乳杆菌XN1904E, 胞外多糖, 培养条件, 优化, 抗氧化能力