培养条件及接触材料对大米中蜡样芽孢杆菌生物被膜形成的影响

Effects of culture condition and contact surface on formation of Bacillus cereus biofilm from rice

通过体外构建分离自大米的蜡样芽孢杆菌（Bacillus cereus）生物被膜（Biofilm,BF）,研究温度、培养时间、碳源、无机盐、p H及接触材料对其生物被膜形成的影响。采用改良的微孔板法培养,通过比浊法、平板计数法判断培养条件对蜡样芽孢杆菌生物被膜形成的影响。实验表明：蜡样芽孢杆菌生物被膜的OD600值在培养24 h达到峰值,48 h后趋于稳定;形成蜡样芽孢杆菌生物被膜最适温度为37℃,最适p H为7.0;在培养基中加入3.0%-6.0%葡萄糖,3.0%蔗糖,1.0%Mg Cl2时分别达到最明显的促进蜡样芽孢杆菌生物被膜形成的效果;0.01%的Ca Cl2可促进蜡样芽孢杆菌生物被膜形成;与有机玻璃、聚氯乙烯相比,不锈钢材料更易形成蜡样芽孢杆菌生物被膜;接触过大米的不锈钢表面比洁净的不锈钢表面更适宜生物被膜的形成,且生物被膜内菌体维持活性时间更长。

Biofilm of Bacillus cereus which separated from rice was cultivated in vitro and the effects of culture condition and contact surface on the biofilm formation were investigated. The bacteria were inoculated in microtiterplate plates to form a biofilm,and the bacterial concentration was measured by turbidimetry and colony counting. Results showed that OD600 of Bacillus cereus biofilm reached the peak after 24 h incubation and became stable after 48 h.The optimal condition for B. cereus biofilm formation was 37 ℃,at the p H 7. 0. Addition of glucose at 3. 0%- 6. 0%,sucrose at 3. 0% and Mg Cl2 at 1. 0% reached the most obvious promotion effect at B. cereus biofilm formation.0. 01% Ca Cl2 could enhance biofilm formation. This research also discovered that B. cereus can form a biofilm with larger biomass on stainless steel compared to polymethyl methacrylate（ PMMA） and polyvinyl chloride（ PVC）,the biofilm formed on the surface of stainless steel pre-treated with rice had higher biomass and sustainability.