摘要
采用胁迫培养的方式,结合扫描电镜(SEM)和傅里叶变换红外分析(FTIR)研究了Pb2+对生物膜胞外聚合物(EPS)的影响,包括Pb2+对蛋白质和多糖产生量及比值(PN/PS)的影响、对EPS中Pb2+质量比的影响、对EPS基团和微观形态的影响。结果表明,Pb2+质量浓度为10 mg/L时,对蛋白质和多糖的产生有抑制作用;Pb2+质量浓度大于等于20 mg/L时,对蛋白质和多糖的产生有促进作用。PN/PS随Pb2+质量浓度升高而增大,在Pb2+质量浓度为40 mg/L时略有下降,说明Pb2+更有利于促进蛋白质的产生。生物膜中Pb2+质量比随Pb2+质量浓度升高而增加,证明Pb2+通过与蛋白质和多糖结合在生物膜上积累。FTIR分析表明,Pb2+的加入会导致羧基基团的振动减弱,羟基出现变形振动、伸缩振动等;SEM图像显示,加入Pb2+后,出现含Pb的白色沉淀物,阻塞了传质通道,使EPS孔洞和通道数目减少。
This paper is aimed to study the impacts of Pb2＋ on the extracellular polymeric substances （EPS） of bio-membranes, including the production of protein and polysacchafide. It also intends to study the effects of Pb2＋ on the PN/PS, the content of Pb2 ＋ in the EPS, on the function groups as well as the micro-morphology of EPS, in which the focus of our research has been put on the study of thestress training, the scanning electron microscopy （SEM） and the Fourier transform infrared analysis （FTIR）. The results of our study indicate that the production both of protein and polysaccharides tended to decrease when Pb2＋ was equal to 10 mg/L; however, when the decrease exceeded 40% with Pb2 ＋ mass concentration ≥ 20 nag/L, the production would be likely to rise. But, as the proteins/polysaccharides （PN/PS） were increasing with the increase of Pb2＋ , a slight decrease would occur on the condition that Pb2＋ Was equal to 40mg/L, with PN/PS remaining higher than that of the baseline. Besides, the content of Pb2 ＋ in EPS tended to increase with the increase of Pb2 ＋ concentration when the contents of EPS in the steel plate and ABS plate were equal to 4.23 mg/g and 5.67 mg/g, respectively, and, when Pb2＋ was 40 mg/L, that is, 12.44 and 11.3 times as much as that of Pb2＋ （which was 10 mg/L）. What is more, the FTIR analysis has found that the adding of Pb2 ＋ tends to weaken the vibration of the carboxyl groups, leading to the deformation and the stretching vibration of the hydroxyl, etc. What is more, the images of SEM also demonstrated the decrease of the numbers of holes and channels of EPS after joining Pb2 ＋ and the appearance of some white sediments. The aforeentioned results demonstrate that the low Pb2＋ concentration is likely to slacken the activities of the microorganisms and the increase of Pb2 ＋ stimulated microorganisms to produce more EPS. Besides, the change of PN/PS also proves that Pb2 ＋ is more advantageous for the generation of protein rather polysaccharide. Since protein plays a more important role in bonding Pb2 ＋ and protecting microorganism cells than the polysaccharide, the Pb2 ＋ has a tendency to accumulate the EPS through the combination with protein and polysaccharide by complexation and electrostatic interaction, which may also lead to the vibration change of the function groups, though hardly any change would take place with the peak shape of the function groups, which implies that Pb2 ＋ turns to be just bonded with them instead of changing their structure. All in all, for the micromorphology, the protein and polysaccharide bonded Pb2＋ tends to form white sediments, which are inclined to block the mass transfer channels of EPS. All the above results we have gained have shown that Pb2 ＋ tends to affect the quantity and proportion of EPS components, the content of Pb2＋ in EPS, the vibration change of the function groups and the micromorphology of EPS.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第4期237-241,共5页
Journal of Safety and Environment
基金
国家自然科学基金项目(50908109
51178208)
昆明理工大学分析测试基金项目(2011302)
关键词
环境学
生物膜
PB2+
胞外聚合物
environment science
biofilm
Pb2＋
extracellular poly-meric substances （EPS）
