单壁碳纳米管对Arthrobacter sp.W1生长及苯酚降解功能的影响

Influence of single-walled carbon nanotubes on the growth and phenol biodegradation characteristics of Arthrobacter sp.W1

单壁碳纳米管(SWCNTs)对大肠杆菌等模式菌株的生长抑制作用明显,为了解SWCNTs对具有环境功能的菌株的作用,以苯酚降解菌Arthrobacter sp.W1为对象,考察不同浓度SWCNTs下菌株W1的生长曲线和苯酚降解曲线,并通过扫描电镜观察、细胞凋亡检测、DNA泄漏量分析和活性氧产量分析考察作用机制.结果表明,特定浓度范围的SWCNTs(0.5-5.0 mg/L)会加快W1的苯酚降解速率,且1.5-2.0 mg/L SWCNTs不抑制W1的生长.SWCNTs在溶液中形成团簇并吸附W1细胞,且对W1产生以物理穿刺为主的毒性作用,但在特定浓度范围的SWCNTs条件下,SWCNTs-菌株-苯酚体系增加了菌体与苯酚的接触机会,从而对W1生长和苯酚降解产生明显的促进作用.本研究结果可为进一步揭示SWCNTs的环境微生物效应提供理论依据.

With the extensive production and application of single-walled carbon nanotubes （SWCNTs）, their potential effects on biological systems and human health have attracted much research attention. Most researches used Escherichia coli as model strain and observed strong antimicrobial activity of SWCNTs, rarely paying attention to the effects of SWCNTs on functional microorganisms. This research investigated the growth curves and degradation curves of a phenol- degrading bacterium Arthrobacter sp. W1 influenced by different concentrations of SWCNTs, through scanning electron microscopic observation, viability test, cellular integrity analysis and reactive oxidative stress analysis. The results showed that 0.5-5.0 mg/L SWCNTs would accelerate phenol degrading process, and 1.5-2.0 mg/L SWCNTs had no antibacterial effects on strain W1. SWCNTs aggregates would adsorb cells with the toxicity mainly caused by physical piercing. While in systems with certain concentrations of SWCNTs, the SWCNTs-cells-phenol coexisting systems would create a suitable microenvironment for W1 growth and phenol degradation. This study would provide theoretical foundation for revealing the microbial effects of SWCNTs.