功能化石墨烯对苯并[a]芘高效降解菌Paracoccus aminovorans HPD-2生长的促进作用

研究石墨烯对微生物生长的影响,深入探讨石墨烯和微生物之间的相互作用,对科学评估石墨烯的生态安全性具有重要的现实意义.本文研究了两种功能化石墨烯(氧化石墨烯和磺化石墨烯)对苯并a]芘高效降解菌Paracoccus aminovorans HPD-2生长的影响,并采用扫描电子显微镜(SEM)、拉曼光谱及红外光谱技术深入探讨了石墨烯与菌HPD-2之间的作用机制.结果表明,两种石墨烯对菌HPD-2生长的影响与培养体系中营养水平有关,石墨烯的种类和浓度也是重要影响因素.低浓度石墨烯(0～10 mg·L~(-1))对菌HPD-2生长无影响,较高浓度石墨烯(100 mg·L~(-1))能够显著促进菌HPD-2的生长(p0.05).两种石墨烯均能促进菌HPD-2胞外聚合物的分泌.与菌HPD-2发生相互作用后,低浓度氧化石墨烯的D峰和G峰的相对强度比值(I_D/I_G)显著提高,结构无序性增加,较高浓度石墨烯与菌HPD-2发生了明显的相互作用,并在菌体表面存在一定程度的堆叠,细胞表面蛋白质、氨基酸和胞外多糖均参与了两者之间的相互作用;相比于氧化石墨烯,磺化石墨烯与菌HPD-2表面的作用较弱.研究结果有助于深入理解和科学评价石墨烯的微生物效应.

Promoting effect of functionalized graphene on the growth of benzo[a]pyrene-degrading bacteria Paracoccus aminovorans HPD-2

Studying the influence of graphene on the growth of microorganisms and deeply exploring the interaction between graphene and microorganisms are of practical significance for scientifically evaluating the ecological safety of graphene. In this paper, the effects of two functional graphene (graphene oxide and sulfonated graphene) on the growth of benzoa]pyrene-degrading bacteria Paracoccus aminovorans HPD-2 were studied. Scanning electron microscopy (SEM), Raman spectroscopy and infrared spectroscopy technology were applied to explore the interaction mechanism between graphene and HPD-2. The results showed that the effects of both graphene on the growth of HPD-2 were related to the nutrient level in the culture system. The type and concentration of graphene were also important factors. Low concentrations of graphene (0~10 mg·L^-1) had no effect on the growth of HPD-2, while higher concentration of graphene (100 mg·L^-1) could significantly promote the growth of HPD-2 (p<0.05). Both types of graphene could increase the secretion of HPD-2 extracellular polymeric substance. After the interaction with HPD-2, the relative intensity ratio (I_D/I_G) at low concentrations of graphene oxide increased significantly, and the structural disorder increased, while the higher concentrations of graphene interacted significantly with HPD-2, and had a certain degree of stack on its surface. Proteins, amino acids and extracellular polysaccharides in cell surface were involved in the interaction. Compared to graphene oxide, the interaction of sulfonated graphene and HPD-2 surface was weaker. The results of this study are helpful to deeply understand and scientifically evaluate the microbial effects of graphene.