解硫胺素类芽孢杆菌（Paenibacillus thiamolyticus SY20）是一株从福建漳州酸笋中分离的抗菌活性菌株，前期已经证明它能产生一种罕见的脂肽类抗菌剂多粘菌素A1。为了提高其产抑菌物质的能力，以该活性菌株为研究对象，以对大肠杆菌的抑菌直径为考察指标，进行产抑菌物质发酵条件优化。首先通过单因素实验探究了不同碳源、氮源、无机盐及添加浓度对菌株产抑菌活性物质的影响；然后采用Plackett-Burman法筛选3个重要因素磷酸氢二铵、KCl和NaCl进行分析；接着通过Box-Behnken中心组合试验确定培养基最优组合；最后在此基础上进行接种量、pH值条件、发酵时间和发酵温度优化以获得最优发酵条件并进行优化方案验证。结果表明：P. thiamolyticus SY20发酵产抑菌物质的最佳培养基配方为麦芽糖20 g/L，棉籽饼粉15 g/L，磷酸氢二铵8 g/L，KCl 10 g/L，NaCl 10 g/L，最佳发酵条件为：pH值为7.5，培养温度28 ℃，发酵时间60 h，优化后发酵上清的抑菌圈直径22.8 mm为优化前（15.2 mm）的1.5倍。优化后该菌株产抑菌活性物质的能力显著提高，该研究为后续大规模分离纯化抑菌物质奠定基础。

Paenibacillus thiaminolyticus SY20 is an antimicrobial strain isolated from acid bamboo shoots in Zhangzhou, Fujian. Previous studies have demonstrated that this species can produce a rare lipopeptide antimicrobial substance, polymyxin A1. To improve the ability of P. thiaminolyticus to produce antimicrobial substances, the active strain was used as the research object, and the antimicrobial diameters against Escherichia coli were used as the investigation index to optimize the fermentation conditions. Single-factor experiments were conducted to evaluate the effects of different carbon sources, nitrogen sources, and inorganic salt types and their concentrations on the production of antimicrobial substances. The three significant factors, namely ammonium phosphate, KCl, and NaCl, were screened and further analyzed using the Plackett-Burman method. The optimal medium combination was determined using a Box–Behnken central composite design. Finally, the inoculation volume, pH value, fermentation time and temperature were optimized to obtain the most effective fermentation conditions, which were then verified experimentally. The results showed that the optimum fermentation medium for producing antimicrobial substances in P. thiaminolyticus SY20 was composed of 20 g/L maltose, 15 g/L cottonseed cake flour, 8 g/L (NH4)2HPO4, 10 g/L KCl, and 10 g/L NaCl. The optimized fermentation conditions were as follows: pH 7.5, fermentation temperature of 28 ℃ , and fermentation time of 60 h. After optimization, the inhibition diameter of the fermented supernatant was 22.8 mm, which was 1.5-fold larger than that before optimization (15.2 mm). The ability of the strain to produce antimicrobial substances was significantly improved, providing a foundation for large-scale isolation and purification of the antibacterial substances.

漳州职业技术学院博士启动基金（ZZYB2207）