培养基相态对菌膜结构和机械性能的调控

Regulation of the structure and mechanical properties of biofilm by medium phase

菌膜(Biofilm)是细菌为了适应不利的生存环境,粘附于基底形成的、由细菌和其分泌的胞外基质(Extracellular Polymeric Substance, EPS)组成的三维类凝胶复合物。具有类凝胶结构的菌膜,已被用于工业污水处理、生物工程和生物电池等领域。然而,如何简单而有效地调控菌膜结构使其更有利于应用依然是一个难题。本研究选取革兰氏阳性菌(枯草芽孢杆菌)和阴性菌(绿脓杆菌)作为模式生物,通过流变学测试和扫描电子显微成像技术研究不同相态(固态和液态)培养基对两种细菌菌膜结构的影响。结果显示:菌膜结构和类凝胶性质依赖于培养基的相态;与液态培养基相比,固态培养基培养细菌形成的菌膜结构松散、但厚度较厚且机械强度更强。本研究为调控菌膜结构和机械性能提供了一种简便的方法,为菌膜在有机污染物吸附和新型生物材料构建方面提供了新思路。

[Background] Bacteria tends to form biofilm to adapt to the unfavorable living environment. Biofilm, a three-dimensional hydrogel-like compound, is composed of bacteria adhering to the substrate and its extracellular polymeric substance （EPS）. Biofilm with gel-like structure has been widely used in industrial wastewater treatment, bioengineering and bio-battery. [Purpose] This study aims to simply and effectively regulate biofilm for practical applications. [Methods] Gram-positive bacteria （Bacillus subtilis） and -negative bacteria （Pseudomonas aeruginosa） were selected as model organisms to investigate the effect of different phase media （solid and liquid） on biofilm structure by theological tests and scanning electron microscopy. [Results] The results showed the gel-like structure of biofilm depended on the medium phase. Compared to the liquid medium, biofilm cultured with solid medium possessed loose, thicker and stronger mechanical strength. [Conclusions] This study provides a simple method for regulating the structure and mechanical properties of biofilm, and also provides insight into the application of biofilm for adsorption of organic pollutants and the design of new biomaterials.