苑志華,林曉鋒,周婷婷,3,陳文祥,張磊峰,鄭煜銘*

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納米銀對(duì)聚磷菌吸磷和釋磷的影響及毒性效應(yīng)

苑志華1,2,林曉鋒1,2,周婷婷1,2,3,陳文祥4,張磊峰4,鄭煜銘1,2*

(1.中國科學(xué)院城市污染物轉(zhuǎn)化重點(diǎn)實(shí)驗(yàn)室,福建 廈門 361021；2.中國科學(xué)院城市環(huán)境研究所,福建 廈門 361021；3.安徽理工大學(xué)地球與環(huán)境學(xué)院,安徽 淮南 232001；4.集美大學(xué)食品與生物工程學(xué)院, 福建 廈門 361021)

利用硼氫化鈉還原硝酸銀,并使用聚乙烯醇(PVA)作為分散劑,制備出分散良好、粒徑為(14±3)nm的納米銀顆粒,考察了其對(duì)聚磷菌()好氧吸磷和厭氧釋磷的影響,以及產(chǎn)生的毒性效應(yīng).結(jié)果表明,在好氧狀態(tài)下,7mg/L的納米銀能夠完全抑制聚磷菌的生長(<0.01),達(dá)到10mg/L時(shí)才能完全抑制聚磷菌的吸磷能力(=0.01);在厭氧狀態(tài)下,大于20mg/L的納米銀才使聚磷菌釋磷能力受到部分抑制(<0.05).活性氧簇(ROS)和掃描電子顯微鏡(SEM)的檢測(cè)結(jié)果表明,納米銀使細(xì)菌體內(nèi)ROS水平降低,部分細(xì)菌菌體表面塌陷,這說明,納米銀不但可以毒害聚磷菌菌體表面,還可以降低菌內(nèi)ROS水平.

納米銀；聚磷菌；好氧吸磷；厭氧釋磷；毒性效應(yīng)

納米銀(AgNPs)具有優(yōu)良的殺菌性能,成為市場上應(yīng)用最廣泛的工程納米材料之一,被大量應(yīng)用在紡織品、食物容器、電子電器、醫(yī)藥和個(gè)人護(hù)理品等商品中[1-4].然而,納米銀被釋放到環(huán)境中,所產(chǎn)生的環(huán)境風(fēng)險(xiǎn)也引起了科學(xué)界的廣泛關(guān)注[5-8].從物質(zhì)流分析來看,消費(fèi)產(chǎn)品中的納米銀受到人類活動(dòng)的影響,一部分會(huì)經(jīng)過下水道系統(tǒng)進(jìn)入城市污水處理廠[9-12],對(duì)污水處理廠中的生物處理系統(tǒng)產(chǎn)生影響,進(jìn)而影響污水處理系統(tǒng)的穩(wěn)定性.

有研究認(rèn)為,納米銀的毒性主要來源于納米顆粒本身和其釋放的銀離子,以及二者所產(chǎn)生的活性氧簇(ROS),其毒性大小與納米銀團(tuán)聚狀態(tài)、顆粒大小和形成的銀復(fù)合物種類有關(guān)[13-16].已有的研究發(fā)現(xiàn):納米銀可以降低污水生物處理系統(tǒng)對(duì)磷的去除效率,主要原因是影響了污泥中的微生物種群結(jié)構(gòu)和抑制了磷去除相關(guān)的酶活性[17-18].而且,納米銀所釋放的銀離子對(duì)除磷效率的影響更大[17].污水中磷的去除主要由活性污泥中的聚磷菌(PAB)完成,聚磷菌通過厭氧釋磷和好氧吸磷,達(dá)到去除磷的目的[19].然而,納米銀對(duì)聚磷菌除磷的影響和毒性效應(yīng)的研究還比較缺乏.本文采用硼氫化鈉還原硝酸銀,并用聚乙烯醇分散,制備了分散良好的納米銀懸浮液,通過研究其對(duì)聚磷菌的影響,得到納米銀對(duì)聚磷菌的毒性效應(yīng).

1 材料與方法

1.1 試劑與菌種

硝酸銀(AgNO3,99.8%)(上海申博化工有限公司);聚乙烯醇(PVA,1750±50,399.0%)(北京索萊寶科技有限公司);銀標(biāo)準(zhǔn)溶液(1000mg/L)(國家有色金屬及電子材料分析測(cè)試中心);蛋白胨和酵母提取物(OXOID(UK)公司);硝酸(GR,65%)和其它化學(xué)試劑(國藥集團(tuán)化學(xué)試劑有限公司),均為分析純或者以上級(jí)別.聚磷菌為(DSM 10555)(德國微生物菌種保藏中心).試驗(yàn)中使用的水為超純水(Milli-Q,USA).

培養(yǎng)基配方為:0.5g/L葡萄糖、0.5g/L蛋白胨、0.5g/L酵母提取物、0.5g/L谷氨酸鈉、0.5g/L KH2PO4、0.1g/L (NH4)2SO4和0.1g/L MgSO4,pH 7.0,培養(yǎng)溫度為30℃,搖床150r/min避光培養(yǎng).

1.2 納米銀的制備與表征

根據(jù)文獻(xiàn)的方法[14],制備納米銀懸浮液,步驟:1mL 14mmol/L的硼氫化鈉加入18mL 0.06wt%聚乙烯醇(PVA)中,再滴加1mL 14mmol/L的硝酸銀,并攪拌10min(避光),制備出納米銀懸浮液.采用透射電子顯微鏡(TEM, Hitachi H-7650,日本)觀察納米銀的形態(tài).

1.3 納米銀對(duì)聚磷菌生長的影響

培養(yǎng)48h后的聚磷菌,使用高速離心機(jī)(CR22GII,日本日立)在5000、4℃離心20min后,倒掉培養(yǎng)基,使用清洗液洗滌后在5000、4℃再次離心20min,倒掉清洗液,再用培養(yǎng)基重懸浮后放在4 ℃冰箱備用.使用OD600定量細(xì)菌的含量.

為了評(píng)估納米銀對(duì)聚磷菌生長的影響,先把適量培養(yǎng)基分裝于250mL已滅菌的三角瓶中,再加入不同濃度的納米銀.最后,加入定量后的細(xì)菌菌液,使三角瓶內(nèi)最后的細(xì)菌OD600為0.05.隨后,加入細(xì)菌和納米銀的培養(yǎng)基放在搖床中按照細(xì)菌生長條件培養(yǎng),并在一定時(shí)間內(nèi)分別檢測(cè)OD600值.為了確定分散劑PVA對(duì)聚磷菌的影響,設(shè)置PVA實(shí)驗(yàn)組,加入與10mg/L納米銀同等劑量的PVA.同時(shí)設(shè)置一組不含納米銀的空白對(duì)照組.實(shí)驗(yàn)均設(shè)置3重復(fù).

1.4 納米銀對(duì)聚磷菌好氧吸磷的影響

按照1.3的實(shí)驗(yàn)步驟,加入納米銀和聚磷菌后的三角瓶,放入搖床中按照細(xì)菌生長條件培養(yǎng),在一定時(shí)間內(nèi)取一定量菌液,經(jīng)過0.22μm濾膜過濾后,用流動(dòng)注射儀(Hach QC8500,USA)檢測(cè)培養(yǎng)基中的磷含量變化.同時(shí),在暴露過程中,取一定量菌液,放入Amicon超濾膜裝置(Millipore 3kDa)中[14],在4℃、5000r/min速度下過濾,過濾液使用電感耦合等離子體發(fā)射光譜儀(ICP-OES,PerkinElmer Optima 7000DV,美國)檢測(cè)Ag+的變化.

1.5 納米銀對(duì)聚磷菌厭氧釋磷的影響

把一定量的培養(yǎng)基分裝到厭氧瓶中,加入除氧劑和氧指示劑,氮吹除氧,壓蓋密封后滅菌.把培養(yǎng)好的菌液收集定量,加入到滅菌后的厭氧瓶中,同時(shí)加入一定量的納米銀懸浮液,放入搖床中,30℃、150r/min避光培養(yǎng).培養(yǎng)48h后,分別用注射器取樣,經(jīng)過0.22μm濾膜過濾后,用流動(dòng)注射儀檢測(cè)培養(yǎng)基中磷含量的變化.

1.6 活性氧簇(ROS)的檢測(cè)

培養(yǎng)48h后的聚磷菌,使用高速離心機(jī)在5000、4℃離心20min后,倒掉培養(yǎng)基,使用清洗液洗滌后再次離心,倒掉清洗液,再用培養(yǎng)基重懸浮,并調(diào)整細(xì)菌濃度為升1.0′106個(gè)/mL.取一定量的細(xì)菌,在30℃條件下,暴露納米銀2h,再用PBS清洗3次,加入熒光探針,按照細(xì)胞內(nèi)ROS試劑盒(Sigma MAK142)的操作說明,利用熒光酶標(biāo)儀在650nm激發(fā)波長、675nm發(fā)射波長下測(cè)定不同納米銀濃度暴露下聚磷菌內(nèi)的ROS水平.

1.7 聚磷菌形態(tài)的變化

按照1.3的實(shí)驗(yàn)步驟,加入納米銀懸浮液到聚磷菌中,在30℃暴露培養(yǎng)48h后,離心倒掉上清液,加入2.5%戊二醛-磷酸鹽緩沖液,固定1h,再使用磷酸鹽緩沖液(pH=7.4)清洗3遍,并依次使用30%、50%、70%、90%和100%酒精脫水,每次各15min,再用100%酒精脫水20min,立即用臨界點(diǎn)干燥儀(Tousimis Samdri-PVT-3D, USA)進(jìn)行干燥.干燥后的樣品進(jìn)行濺射噴金,使用掃描電子顯微鏡(SEM, Hitachi S-4800, Japan)觀察聚磷菌接觸納米銀前后的形態(tài)變化,并進(jìn)行能譜(Genesis XM2)分析.

1.8 數(shù)據(jù)處理

每組試驗(yàn)單獨(dú)重復(fù)3次,結(jié)果取平均值.數(shù)據(jù)采用Origin8.1軟件分析.

2 結(jié)果與討論

2.1 納米銀的形態(tài)

圖1顯示出納米銀呈圓球狀,分散效果良好,顆粒大小不均勻.經(jīng)統(tǒng)計(jì)分析,其顆粒平均直徑為(14±3)nm.

圖1 納米銀的TEM

2.2 納米銀對(duì)聚磷菌生長的影響

使用對(duì)數(shù)期的生長率表示聚磷菌的活性,并以此計(jì)算納米銀對(duì)聚磷菌的抑制效率.圖2說明了分散劑PVA對(duì)聚磷菌生長沒有影響,而納米銀對(duì)聚磷菌生長具有一定的抑制作用.如圖2所示,未暴露納米銀的聚磷菌顯示正常的生長周期,包括遲緩期、對(duì)數(shù)期和穩(wěn)定期.然而,暴露納米銀后,細(xì)菌生長受到了一定的影響,1mg/L的納米銀對(duì)聚磷菌的生長僅產(chǎn)生了微量的影響,其抑制效率為3.3%,影響較小.當(dāng)納米銀增加到3mg/L時(shí),其對(duì)聚磷菌對(duì)數(shù)生長期有一定的抑制(>0.05),抑制效率達(dá)到22.2%.然而,隨著暴露時(shí)間達(dá)到58h,聚磷菌的生長逐漸恢復(fù)到未暴露納米銀的水平,這可能由于納米銀接觸聚磷菌后,抑制了部分細(xì)菌的活性,但是隨著暴露時(shí)間的延長,納米銀受到菌體、培養(yǎng)基成分等的影響,出現(xiàn)了團(tuán)聚、形態(tài)轉(zhuǎn)化等[14,20-21],進(jìn)而毒性降低,對(duì)細(xì)菌的影響變小[22].因此,聚磷菌又逐漸恢復(fù)到未暴露納米銀的生長狀態(tài).當(dāng)納米銀達(dá)到5mg/L時(shí),其對(duì)聚磷菌生長的抑制效率達(dá)到70.3%(<0.05),但是,隨著接觸時(shí)間的延長,聚磷菌的生長狀態(tài)有逐步恢復(fù)的趨勢(shì)(圖2).而納米銀的加入量達(dá)到7mg/L時(shí),聚磷菌的生長被完全抑制(<0.01),即使暴露時(shí)間達(dá)到58h,聚磷菌的活性仍未恢復(fù).這說明,當(dāng)納米銀達(dá)到7mg/L以上時(shí),能夠完全抑制聚磷菌的生長.已有的研究發(fā)現(xiàn),相同粒徑和分散劑的納米銀使氨氧化細(xì)菌完全抑制的濃度為3mg/L[14],而使聚磷菌生長完全停止的濃度為7mg/L,這說明不同細(xì)菌由于本身結(jié)構(gòu)特征、生長環(huán)境等因素的不同,表現(xiàn)出對(duì)納米銀不同的耐受程度[23-24].

2.3 納米銀對(duì)聚磷菌好氧吸磷的影響

在好氧培養(yǎng)中,聚磷菌在多聚磷酸鹽激酶(PPK)的作用下,可以過量吸收培養(yǎng)基中的磷酸鹽,以多聚磷酸鹽(poly-P)的形式存儲(chǔ),其反應(yīng)過程為:ATP+ (poly-P)?ADP+(poly-P)+1[25].如圖3所示,未加納米銀的聚磷菌吸收培養(yǎng)基中的磷,使培養(yǎng)基中的磷含量逐漸降低,48h時(shí)對(duì)磷的吸收達(dá)到最大值.而加入納米銀后,聚磷菌活性受到抑制,磷吸收能力減弱.納米銀在1~7mg/L時(shí),對(duì)聚磷菌好氧吸磷能力均有一定程度的影響,當(dāng)達(dá)到10mg/L時(shí),完全抑制了聚磷菌的吸磷能力(=0.01).而7mg/L的納米銀已經(jīng)完全抑制了聚磷菌的生長(圖2),這說明該濃度下聚磷菌的裂殖受到影響,但是部分細(xì)菌仍具有一定的活性.納米銀對(duì)細(xì)菌產(chǎn)生毒性的原因是[6,14-15,26]:(1)釋放的自由Ag+,可以破壞細(xì)胞ATP的產(chǎn)生和DNA的復(fù)制,最終使細(xì)胞死亡;(2)誘導(dǎo)產(chǎn)生強(qiáng)氧化性ROS,進(jìn)而破壞細(xì)胞結(jié)構(gòu);(3)納米粒子直接損傷細(xì)胞膜.

圖3反映出納米銀濃度小于5mg/L時(shí),并沒有引起暴露體系中銀離子含量的增加,而大于7mg/L時(shí),銀離子含量才有很少程度的上升.這說明,在該暴露體系中,納米銀對(duì)聚磷菌的毒性并不是主要由Ag+引起的.納米銀在溶解氧和質(zhì)子存在時(shí),很容易被氧化而釋放出自由Ag+[27],然而釋放的Ag+很快被培養(yǎng)體系中的其它離子絡(luò)合[27-28],因此,檢測(cè)時(shí),自由Ag+的含量很少.納米銀對(duì)細(xì)菌的毒性主要涉及抑制蛋白功能、基因表達(dá)和能量產(chǎn)生等[14],對(duì)聚磷菌好氧吸磷的抑制也可能是影響到有關(guān)除磷酶的活性[17,29].

2.4 納米銀對(duì)聚磷菌厭氧釋磷的影響

在厭氧環(huán)境中,長鏈多聚磷酸鹽在多聚磷酸鹽酯酶(PPX)的催化下,不斷釋放出無機(jī)磷酸鹽,達(dá)到厭氧釋磷的目的,其反應(yīng)過程為:(poly-P)?(poly-P)-1?(Pi)[25].如圖4所示,厭氧反應(yīng)48h后,未加納米銀的體系中,無機(jī)磷含量達(dá)到78.3mg/L,而加入5,10mg/L納米銀時(shí),體系中磷含量均未受到明顯影響.但是,加入20,30mg/L納米銀后,體系中磷含量降低,說明聚磷菌釋磷受到一定程度的抑制(<0.05).納米銀對(duì)聚磷菌釋磷的影響,可能通過抑制PPX的活性,來抑制多聚磷酸鹽的分解,從而抑制了無機(jī)磷的釋放[17,29].從整體上看,納米銀的毒性在厭氧狀態(tài)下更小,這是因?yàn)榧{米銀在厭氧狀態(tài)下,銀離子的釋放和ROS的產(chǎn)生都受到了明顯的抑制,再加上納米銀顆粒團(tuán)聚和被其它離子絡(luò)合[27,30],其毒性被大量降低.

圖4 納米銀對(duì)聚磷菌厭氧釋磷的影響

2.5 細(xì)菌內(nèi)ROS的變化

圖5顯示在好氧條件下,加入不同濃度的納米銀后,細(xì)胞內(nèi)ROS的水平變化.納米銀加入后,細(xì)胞內(nèi)ROS呈現(xiàn)降低趨勢(shì).之前的研究發(fā)現(xiàn),暴露納米銀后的細(xì)菌,細(xì)胞內(nèi)ROS水平上升,而升高的ROS則是導(dǎo)致細(xì)菌死亡的重要原因之一[26,31-32].然而,聚磷菌暴露納米銀后,菌體內(nèi)ROS水平并沒有升高,反而呈現(xiàn)一定的降低趨勢(shì),這與Hsiao等[33]的發(fā)現(xiàn)一致.當(dāng)納米銀進(jìn)入細(xì)胞內(nèi),很快被ROS氧化,并在細(xì)胞內(nèi)釋放出自由Ag+,Ag+對(duì)細(xì)胞產(chǎn)生毒性,引起細(xì)胞死亡,同時(shí),細(xì)胞內(nèi)ROS水平被降低[33],這也很好地解釋了納米銀對(duì)聚磷菌的毒性來源.納米銀含量越高,聚磷菌活性越低(圖2和圖3),生長受到的抑制也越大,但是培養(yǎng)基中(細(xì)菌菌體外)的Ag+并沒有明顯增加(圖3),細(xì)菌菌體內(nèi)的ROS水平也沒有升高.因此,納米銀對(duì)聚磷菌的毒性除了直接作用于聚磷菌菌體外,很可能與菌體內(nèi)的ROS水平密切相關(guān).

圖5 納米銀對(duì)細(xì)菌內(nèi)ROS的影響

2.6 聚磷菌表面形態(tài)的變化

如圖6所示,聚磷菌暴露納米銀前,菌體表面光滑,沒有出現(xiàn)破損.經(jīng)過10mg/L納米銀暴露后,部分細(xì)菌細(xì)胞壁出現(xiàn)塌陷現(xiàn)象,然而,更多的細(xì)菌表面并沒有出現(xiàn)特別明顯的變化.實(shí)驗(yàn)結(jié)果顯示,10mg/L的納米銀已經(jīng)完全抑制了細(xì)菌的生長(圖2),同時(shí),也使其喪失了吸磷能力(圖3),但是在此濃度下,聚磷菌表面形態(tài)受到的影響有限,僅有部分出現(xiàn)塌陷.之前的研究已經(jīng)發(fā)現(xiàn),納米銀釋放的銀離子,可以作用于細(xì)菌的細(xì)胞膜,與細(xì)胞膜上的蛋白成分結(jié)合[31,34],最后引起細(xì)胞膜的破裂[14,31],但是,釋放的銀離子主要被溶液中的其它離子絡(luò)合,僅少數(shù)銀離子作用于細(xì)胞膜上[31],所以,對(duì)細(xì)胞膜的影響有限.Yuan等[14]的研究也發(fā)現(xiàn),在納米銀完全抑制濃度下,多數(shù)氨氧化細(xì)菌表面也沒有出現(xiàn)明顯變化,但是,內(nèi)部細(xì)胞核已經(jīng)完全解體.結(jié)合了ROS的結(jié)果來看,納米銀可能透過細(xì)胞膜,進(jìn)入細(xì)胞內(nèi)部,進(jìn)而對(duì)聚磷菌產(chǎn)生毒性效應(yīng).

箭頭處為菌體塌陷部位

因此,納米銀對(duì)聚磷菌的毒性很可能主要是由于納米銀進(jìn)入聚磷菌內(nèi)部;此時(shí),細(xì)胞內(nèi)產(chǎn)生的ROS氧化了納米銀[31],使其釋放出銀離子;銀離子進(jìn)而對(duì)菌體內(nèi)物質(zhì)產(chǎn)生影響,如抑制磷代謝有關(guān)的酶;最后,使聚磷菌生長和除磷有關(guān)的活動(dòng)停止.

2.7 納米銀對(duì)污水生物除磷影響的啟示

以上研究可以得知,在不同的條件下,聚磷菌純菌對(duì)納米銀暴露表現(xiàn)出不同的耐受程度.在好氧條件下,10mg/L的納米銀才可以完全抑制聚磷菌的吸磷能力,然而,1mg/L的納米銀對(duì)聚磷菌的吸磷行為已經(jīng)表現(xiàn)出一定的不利影響(圖3),在厭氧條件下,納米銀在20mg/L時(shí)才會(huì)產(chǎn)生影響,影響相對(duì)較小(圖4).這說明納米銀對(duì)聚磷菌的影響在好氧條件下較為明顯.不同的文獻(xiàn)中都發(fā)現(xiàn)了納米銀能夠降低污水生物除磷的效率[18,35-37],主要是影響了細(xì)菌的種群結(jié)構(gòu)和除磷有關(guān)的酶活性[17,35],從納米銀和銀離子的對(duì)比來看,銀離子對(duì)除磷的影響遠(yuǎn)遠(yuǎn)大于納米銀的影響[17].因此,如果在厭氧條件下銀離子釋放得以控制[30,38],同時(shí),在環(huán)境條件的影響下,單個(gè)納米銀顆粒很快團(tuán)聚成大顆粒[39-40],其進(jìn)入聚磷菌內(nèi)部的可能性就大量降低.因此,在此情況下,納米銀對(duì)污水廠聚磷菌的影響就會(huì)相對(duì)較小.但是,納米銀可以在污泥中富集[41],富集納米銀后的污泥在一定條件下釋放出的銀離子[41],則提高了對(duì)污水除磷影響的可能性.綜上所述,關(guān)注納米銀對(duì)聚磷菌和污水生物除磷的影響,更應(yīng)集中在納米銀含量上,污水廠進(jìn)水中納米銀低于1mg/L時(shí),對(duì)聚磷菌的影響是可以忽略的.

3 結(jié)論

3.1 利用化學(xué)法制備出分散良好、粒徑為(14±3)nm納米銀顆粒,其在好氧狀態(tài)下,7mg/L時(shí)能夠完全抑制聚磷菌的生長.

3.2 納米銀能夠抑制聚磷菌的好氧吸磷和厭氧釋磷能力,且對(duì)好氧吸磷的抑制作用更強(qiáng),10mg/L時(shí)能夠使聚磷菌完全失去吸磷能力.

3.3 納米銀對(duì)聚磷菌的毒性效應(yīng)除了直接作用于細(xì)菌菌體表面外,也與細(xì)菌菌體內(nèi)ROS水平密切相關(guān).

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Effect of silver nanoparticles on phosphorus uptake and release of polyphosphate-accumulating bacteria and toxic effect.

YUAN Zhi-hua1,2, LIN Xiao-feng1,2, ZHOU Ting-ting1,2,3, CHEN Wen-xiang4, ZHANG Lei-feng4, ZHENG Yu-ming1,2*

(1.Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China；2.Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China；3.School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China；4.College of Food and Biological Engineering, Jimei University, Xiamen 361021, China)., 2018,38(8)：2990~2996

Silver nanoparticles (AgNPs) were obtained from the reduction of silver nitrate by sodium borohydride in the stabilizing agent of polyvinyl alcohol (PVA). The as-prepared AgNPs demonstrated an excellent property of dispersibility, with the nanoparticle size of (14±3) nm. The AgNPs were used to investigate the effect of silver nanoparticles on phosphorus uptake and release of phosphorus-accumulating bacteria (PAB) and toxic effect. The results showed that 7mg/L of AgNPs totally inhibited the growth of PAB (<0.01), and 10mg/L of AgNPs completely suppressed the phosphorus uptake ability of PAB under aerobic condition (=0.01). Under the anaerobic condition, AgNPs with concentration higher than 20mg/L only partly inhibited the phosphorus release of PAB (<0.05). The results indicated that AgNPs decreased the ROS level of PAB, and made the partial collapse of bacteria surface structure by the SEM. These revealed that AgNPs can decrease the ROS of bacteria besides the direct effect on the bacteriasurface membrane structure, which both might be the important reasons for AgNPs toxicity on PAB.

Silver nanoparticles；polyphosphate-accumulating bacteria；aerobic phosphorus uptake；anaerobic phosphorus release；toxic effect

X171.5

A

1000-6923(2018)08-2990-07

苑志華(1983–),河南周口人,助理研究員,博士,主要研究方向?yàn)榧{米材料毒理和廢水處理技術(shù).發(fā)表論文20余篇.

2018-01-21

國家自然科學(xué)基金資助項(xiàng)目(21407142);廈門市科技計(jì)劃項(xiàng)目(2017S0065);福建省科技計(jì)劃項(xiàng)目(2016H0042)

* 責(zé)任作者, 研究員, ymzheng@iue.ac.cn