管网生物膜菌株胞外聚合物的提取方法比较

以饮用水管网生物膜样品中一株强成膜能力的菌株Pleomorphomonas oryzae作为研究对象,考察了8种方法(高速离心法、超声法、加热法、EDTA法、H2SO4法、NaOH法、SDS法、甲醛法)对菌株胞外聚合物(EPS)的提取效果,并结合三维荧光光谱(EEM)和傅立叶红外光谱(FTIR)对提取的EPS进行成分分析.结果表明,EDTA法和H2SO4法既能提高EPS的提取效率,提取量分别为64.77 mg.g-1SS和74.43 mg.g-1SS,是离心方法提取量的1.62倍和1.86倍,又不会在提取过程中对菌株细胞造成破坏,是较为理想的EPS提取方法.EEM分析进一步证实,NaOH法对菌株细胞破坏严重,造成EPS成分变化较大.FTIR分析则说明,化学提取方法相较于物理提取方法会引入杂质对组分测定造成干扰.

Comparison of extraction methods for extracellular polymeric substances from a drinking water biofilm-forming bacteria

Drinking water distribution systems(DWDS) often face the problem of biofilm formation,which results in microbial contamination,and furthermore influence the water quality and population health.The extracellular polymeric substances(EPS) is the major component of biofilm which accounts for over 90%,and its physical and chemical properties have effects on biofilm adhesion and formation.Eight methods for extracting EPS from a drinking water distribution system related bacteria,Pleomorphomonas oryzae,(centrifugation,sonication,heating,EDTA,H2SO4,NaOH,SDS,formaldehyde) were investigated,and then three-dimensional excitation and emission matrix(EEM) fluorescence spectroscopy and Fourier transform infrared(FTIR) spectroscopy were used to supplement the chemical analysis.The results showed that the EDTA and H2SO4 method were efficient and did not cause cell disruption.These two methods obtained 64.77 mg · g-1 SS and 74.43 mg · g-1 SS from bacterial culture,higher than that of the centrifugation method by 1.62 and 1.86 times,respectively.EEM fluorescence spectra of EPS extracted by NaOH method indicates that the method was so severe that cell disruption and EPS degradation might be induced.For the EPS FTIR analysis,no significant difference was observed among all the physical methods.However,EPS by chemical methods showed particular IR bands which suggest that the contents of EPS composition changed.