熊 英,向 斯,2,程 凱*

一株高適應(yīng)性Nitrosomonas eutropha CZ-4的脫氨特性

熊 英1,向 斯1,2,程 凱1*

(1.湖北工業(yè)大學(xué)資源與環(huán)境工程學(xué)院,河湖生態(tài)修復(fù)與藻類利用湖北省重點(diǎn)實(shí)驗(yàn)室,湖北 武漢 430068；2.武漢微盛科創(chuàng)環(huán)境生物科技有限公司,湖北 武漢 430068)

從垃圾滲濾液中分離得到了一株亞硝化單胞菌CZ-4,其16S rDNA序列與C91的相似性達(dá)99%.研究了pH值、溫度、游離亞硝酸濃度、鹽度等對(duì)其生長的影響,并測(cè)試了其在垃圾滲濾液、黑臭水和富營養(yǎng)化湖水中的脫氨效果.結(jié)果表明,該菌的最適生長pH值為7.3~8.7,最適生長溫度為30.9℃,游離亞硝酸和鹽度對(duì)該菌的半數(shù)抑制濃度分別約為0.11mg/L與2%.在最佳發(fā)酵條件下,該菌的最大氨氮去除速率為58mg/(L×h),最短倍增時(shí)間為8.2h;在不同類型的污水/地表水(初始氨氮濃度為0.66~603mg/L)中,該菌的最大氨氮去除速率為11.4mg/(L×h),最短倍增時(shí)間為10.9h,最低殘余氨氮濃度為0.11mg/L.

自養(yǎng)氨氧化菌；垃圾滲濾液；亞硝化單胞菌；氨氮去除速率；倍增時(shí)間

氨氮是造成水體富營養(yǎng)化和黑臭的重要原因.生物硝化脫氨[1]是主流的脫氨方式,包括氨氧化和亞硝氮氧化兩步[2],而氨氧化(將氨氮氧化為亞硝氮)正是硝化的限速步驟[3-4].污水處理系統(tǒng)中的氨氧化主要由自養(yǎng)氨氧化細(xì)菌(AOB)完成.AOB包括亞硝化單胞菌屬()等5個(gè)屬[3],而亞硝化單胞菌屬在污水和富營養(yǎng)化地表水中分布最廣、數(shù)量最多[5],對(duì)氨氧化的貢獻(xiàn)最大[6-7].

亞硝化單胞菌以氨為唯一能源,以CO2為碳源,對(duì)環(huán)境條件極度敏感[3,8],易受溫度、pH值、鹽度、游離氨(FA)和游離亞硝酸(FNA)濃度等多種因素的影響[9-10].如不適的溫度[11]和低pH值導(dǎo)致的高FNA濃度均會(huì)抑制氨氧化[12],而高鹽度則會(huì)通過增大細(xì)胞滲透壓影響氧和底物的傳遞,使氨氧化速率下降[13].目前,雖有適應(yīng)上述單一因素的亞硝化單胞菌的報(bào)道,但單株亞硝化單胞菌對(duì)多種因素均具有較高適應(yīng)性的案例尚未見報(bào)道.

不同的亞硝化單胞菌對(duì)FA的親和力差異較大[14],如和等對(duì)FA的親和力較高,適合在低FA環(huán)境中生長,而在高FA環(huán)境中則有較長的延遲期[15];而等對(duì)FA的親和力較低,適合在高FA環(huán)境中生長,但在低FA條件下的競(jìng)爭(zhēng)力較差[16-17].迄今為止,關(guān)于單株亞硝化單胞菌在不同F(xiàn)A濃度條件下均具有較高親和力的研究也鮮見報(bào)道.

本文分離篩選得到一株AOB,通過研究pH值、溫度、FNA濃度、鹽度等對(duì)其生長的影響,發(fā)現(xiàn)該菌在不同F(xiàn)A濃度下均能有效生長(脫氨),且能夠耐受較高濃度的FNA和鹽度,并適應(yīng)較寬的溫度和pH值范圍,對(duì)于深入研究其適應(yīng)機(jī)理并開發(fā)其應(yīng)用價(jià)值具有重要意義.

1 材料與方法

1.1 培養(yǎng)基

向液體基礎(chǔ)培養(yǎng)基[18]中加入適量1mol/L的氫氧化鈉溶液調(diào)節(jié)pH=7.8[19],固體培養(yǎng)基中的瓊脂粉含量為1.8%.

1.2 分離純化

將湖南郴州某垃圾滲濾液處理廠的活性污泥離心(4℃,6500r/min,15min)后,用滅菌生理鹽水洗滌3次去除亞硝氮,按1%的體積比接種于基礎(chǔ)培養(yǎng)基中,27℃,200r/min振蕩培養(yǎng),5d后用格里斯試劑檢測(cè)亞硝氮的積累情況.將亞硝氮陽性樣品涂布平板,27℃培養(yǎng)5d后挑取單菌落接種于基礎(chǔ)培養(yǎng)基中,27℃,200r/min振蕩培養(yǎng)5~7d,對(duì)亞硝氮陽性樣品進(jìn)行3輪平板劃線純化.純化后的樣品經(jīng)結(jié)晶紫染色[20]后油鏡鏡檢.

1.3 16S rDNA測(cè)序和系統(tǒng)發(fā)育樹構(gòu)建

采用通用引物27F和1492R[21]擴(kuò)增16S rDNA片段,PCR反應(yīng)體系:taq酶(15U/μL)0.1μL;緩沖液2μL;dNTP混合液(2.5mmol/L)1.6μL;模4μL;上下游引物各0.15μL;超純水12μL.反應(yīng)條件: 94℃預(yù)變性4min;94℃變性25s,58℃退火20s,72℃延伸30s,25個(gè)循環(huán);72℃最終延伸5min.PCR產(chǎn)物經(jīng)上海生工測(cè)序,再經(jīng)Blastn比對(duì),并通過MEGA5.0的鄰接法構(gòu)建系統(tǒng)發(fā)育樹.

1.4 發(fā)酵條件的優(yōu)化與驗(yàn)證

1.4.1 接種液的制備 將菌種保藏液離心(4℃, 6500r/min,15min)洗滌3次后,取1mL接種到100mL基礎(chǔ)培養(yǎng)基中,27℃,200r/min振蕩培養(yǎng)至亞硝氮積累速率達(dá)到約100mg/(L×d)時(shí)(需3~5d)作為接種液.

1.4.2 鹽度和FNA濃度對(duì)氨氮去除效果的影響 (1)鹽度的影響向100mL鹽度(以NaCl計(jì))分別為0.2%、0.5%、1%、2%、4%和6%的基礎(chǔ)培養(yǎng)基中加入1mL接種液,27℃,200r/min振蕩培養(yǎng)5d,間隔取樣測(cè)定氨氮濃度.(2)FNA濃度的影響向100mL亞硝氮濃度分別為0,500,1000,2000和4000mg/L的基礎(chǔ)培養(yǎng)基(初始pH值均為7.8,其FNA濃度分別為0,0.06,0.11,0.23和0.46mg/L)中加入1mL接種液,27 ℃,200r/min振蕩培養(yǎng)5d,間隔取樣測(cè)定氨氮濃度.

1.4.3 初始pH值和溫度對(duì)氨氮去除率(NRR)的影響 (1)初始pH值的影響向100mL初始pH值分別為7.3、8.0和8.7的基礎(chǔ)培養(yǎng)基中加入1mL接種液(設(shè)3平行),30℃,200r/min振蕩培養(yǎng)3d后測(cè)定氨氮濃度.(2)溫度的影響向100mL初始pH值為8.0的基礎(chǔ)培養(yǎng)基中加入1mL接種液(設(shè)3平行),分別于26,30和34℃,200r/min振蕩培養(yǎng)3d后測(cè)定氨氮濃度.(3)溫度和初始pH值的聯(lián)合作用采用響應(yīng)面法,利用Design-Export軟件設(shè)計(jì)2因素5水平3平行的試驗(yàn)分組,pH值范圍7.5~8.5,溫度范圍27~33℃.向100mL基礎(chǔ)培養(yǎng)基中加入1mL接種液,于200r/min振蕩培養(yǎng)3d后,測(cè)定氨氮濃度,并繪制響應(yīng)曲面.

1.4.4 補(bǔ)料發(fā)酵 向20L發(fā)酵罐中裝入10L基礎(chǔ)培養(yǎng)基,并接種500mL接種液.試驗(yàn)組(根據(jù)1.4.3的結(jié)果)發(fā)酵條件為:溫度30.9℃,pH=8.2;對(duì)照組發(fā)酵條件為:溫度27℃,pH=7.8.兩組均采用1mol/L碳酸氫鈉自動(dòng)控制pH值.發(fā)酵期間,當(dāng)氨氮濃度降至約300mg/L時(shí),補(bǔ)充氯化銨溶液使其達(dá)到500mg/L.

1.5 對(duì)不同類型污水的脫氨測(cè)試

1.5.1 菌劑的制備方法 將補(bǔ)料發(fā)酵的產(chǎn)物離心(4℃,6500r/min,15min)洗滌3次去除亞硝酸鹽作為菌劑.

1.5.2 垃圾滲濾液中的脫氨測(cè)試 向100mL垃圾滲濾液中接種1mL菌劑,對(duì)照組不接種,31℃,200r/ min振蕩培養(yǎng),48h后測(cè)氨氮與亞硝氮濃度.

1.5.3 在富營養(yǎng)化湖泊水中的脫氨測(cè)試 向100mL三種湖水(湯遜湖、南湖和野芷湖)中分別接種1mL菌劑,對(duì)照組不接種,31℃,200r/min振蕩培養(yǎng), 12h后測(cè)氨氮濃度.

1.5.4 在黑臭河水中的脫氨測(cè)試 向100mL黑臭水(巡司河水)中接種0.1mL菌劑(較低的接種劑量能夠明顯延長培養(yǎng)時(shí)間,從而有充足的時(shí)間進(jìn)行多次測(cè)量以得到較準(zhǔn)確的最短倍增時(shí)間),對(duì)照組不接種,31℃, 200r/min振蕩培養(yǎng),每隔12h測(cè)氨氮濃度.

上述實(shí)驗(yàn)組與對(duì)照組均設(shè)3平行.

1.6 測(cè)試與計(jì)算方法

分別采用納氏試劑法和N-(1-奈基)-乙二胺光度法測(cè)定氨氮和亞硝氮[22];根據(jù)氨氮去除速率的變幅[19]計(jì)算倍增時(shí)間(h)[23];采用Anthonisen等[24]的方法計(jì)算FA濃度(mg/L)和FNA濃度(mg/L).

1.7 統(tǒng)計(jì)方法

采用Origin作圖;采用SPSS進(jìn)行正態(tài)性檢驗(yàn)和方差分析(多重比較采用LSD法);采用Design- Export軟件的二階模型進(jìn)行響應(yīng)面試驗(yàn)的方差分析與回歸分析.

2 結(jié)果與討論

2.1 細(xì)菌的形態(tài)和系統(tǒng)發(fā)育

分離純化得到一株AOB,該菌呈短桿狀(0.66~ 0.86)×(1.52~1.75)mm(見圖1),具有明顯的運(yùn)動(dòng)性,符合的特征[3].且其16S rDNA序列(Genbank序列號(hào)為MH999419[25])與已知的亞硝化單胞菌的相似度為97%~99%,其系統(tǒng)發(fā)育樹(圖2)顯示該菌與C91的遺傳距離最近(相似度為99%),考慮到該菌分離于郴州垃圾滲濾液,故將其命名為CZ-4.

與同屬的其它亞硝化單胞菌相比,在高氨氮環(huán)境中占比最高[12],常分布于污水處理廠等高氨環(huán)境中[3,26-27],如Schmidt等[25]從牛糞中分離到了N904.而CZ-4菌也來源于垃圾滲濾液(其氨氮濃度高達(dá)500~1000mg/L),與同樣來源于污水處理廠的C91[6]的相似度高達(dá)99%.

圖1 N.eutropha CZ-4的光學(xué)顯微照片

圖2 N.eutropha CZ-4的系統(tǒng)發(fā)育樹

2.2 環(huán)境因素對(duì)CZ-4菌的影響

2.2.1 鹽度和FNA濃度對(duì)CZ-4菌的抑制效應(yīng) 由圖3a可見,鹽度能夠顯著影響氨氮去除效果(<0.05):培養(yǎng)5d時(shí),鹽度2%條件下的NRR為52%,而鹽度0.2%時(shí)的NRR為94%,說明CZ-4的半數(shù)抑制鹽度約為2%,明顯高于已知的亞硝化單胞菌(見表1).鹽度是影響AOB生長的重要因素,高鹽度使細(xì)胞滲透壓增大,進(jìn)而干擾底物和氧的傳遞并影響氨氧化速率[13],而微生物的耐鹽能力則可能與蛋白質(zhì)中的酸性氨基酸的含量有關(guān)[28-29].從應(yīng)用上看,由于AOB的發(fā)酵過程中需要補(bǔ)堿(維持pH值穩(wěn)定),鹽度會(huì)隨之增加,較高的耐鹽能力將有利于該菌的補(bǔ)料發(fā)酵生產(chǎn)及在高鹽廢水中的應(yīng)用.

FNA既是氨氧化的產(chǎn)物,也會(huì)對(duì)AOB產(chǎn)生毒性[24,27],因此FNA濃度也是AOB的重要影響因素[38].由圖3b可見,FNA濃度能顯著影響氨氮去除效果(<0.05):培養(yǎng)5d時(shí),0.11mg/L FNA組的NRR為56%,而空白組的NRR則為94%,說明FNA對(duì)該菌的半數(shù)抑制濃度大于0.11mg/L;此外,0.23mg/L FNA組仍能夠有效去除氨氮,說明該菌對(duì)FNA的最大耐受濃度應(yīng)高于0.23mg/L,與Ms1[33]類似,高于19718[23,31-32]、spAL212[35-36]和C91[3,31]等多數(shù)亞硝化單胞菌,僅明顯低于KYUHI-S[37].迄今為止,FNA對(duì)AOB影響機(jī)制的研究尚不充分[39],僅Stein等[31-32]發(fā)現(xiàn)FNA對(duì)3種AOB的影響機(jī)制各不相同,包括了特異性抑制氨單加氧酶(AMO),抑制AMO基因或一氧化氮還原酶基因的轉(zhuǎn)錄等.從應(yīng)用的角度,較高的FNA耐受能力不但有利于該菌的補(bǔ)料發(fā)酵生產(chǎn),而且有利于將該菌應(yīng)用于短程硝化-反硝化等以亞硝氮為關(guān)鍵中間產(chǎn)物的脫氮工藝[40].

圖3 鹽度和FNA濃度對(duì)脫氨效果的影響

表1 不同亞硝化單胞菌對(duì)若干環(huán)境因子的適應(yīng)性

注:a不低于最適pH值條件下的NRR的80%;b半數(shù)抑制鹽度;c最大耐受鹽度,n.d.為未檢出.

圖4 初始pH值和溫度對(duì)NRR的影響

2.2.2 溫度和pH值對(duì)CZ-4菌的影響 由圖4可見,盡管30和34℃的NRR均顯著高于26℃的NRR (<0.05),但該菌在26℃的NRR仍達(dá)到了最大NRR的58%.類似的,盡管初始pH=8.0的NRR顯著高于pH=7.3的NRR(<0.05),但pH=8.7的NRR也能達(dá)到最大NRR的91%,說明適宜CZ-4菌生長的pH值范圍至少為pH=7.3~8.7.

根據(jù)響應(yīng)面試驗(yàn)的結(jié)果,溫度和初始pH對(duì)NRR影響的回歸方程為:

NRR=-2356.90+333.99 ×+68.65×+0.22××

-20.87×2-1.14×2(1)

式中:為溫度,℃;為初始pH值.求解后的最佳培養(yǎng)條件為:溫度30.9℃(<0.05),初始pH值為8.17 (<0.05),溫度與初始pH值之間無交互作用(>0.05).圖5是該回歸方程的三維立體響應(yīng)曲面,顯示溫度的響應(yīng)面彎曲度比初始pH值更大,說明溫度對(duì)氨氮去除率的影響較大.

圖5 溫度和初始pH值的聯(lián)合作用對(duì)NRR的影響

根據(jù)響應(yīng)面試驗(yàn)的結(jié)果,優(yōu)化了補(bǔ)料發(fā)酵的溫度和pH值,結(jié)果表明(圖6):盡管優(yōu)化前后的平均氨氮去除速率(分別為21.85和18.65mg/(L×h))和最大氨氮去除速率(分別為48.45和57.59mg/(L×h))的變化均不大,但達(dá)到最大氨氮去除速率的時(shí)間從239.5h大幅度縮短至79.5h,而最短倍增時(shí)間也由48.5h減少至8.2h.說明優(yōu)化后的溫度和pH值條件能夠明顯加速CZ-4菌的生長,從而大幅縮短發(fā)酵周期.

圖6 補(bǔ)料發(fā)酵過程中氨氮去除速率的變化曲線

溫度是影響AOB活性的重要因素[41],多數(shù)AOB的脫氨活性在10~30℃之間隨升溫而增加[42-43].但CZ-4菌的最適生長溫度為30.9℃,明顯高于其它亞硝化單胞菌(表1),將有利于降低該菌在發(fā)酵生產(chǎn)時(shí)的降溫難度.此外,該菌在26~34℃時(shí)均保持較高的脫氨活性,也有利于在不同季節(jié)和不同溫度的污水中應(yīng)用該菌.

氨氮是AOB的能源與氮源,但只有FA才能透過細(xì)胞膜而被AOB所利用[2],故必須提供足夠的FA才能支撐氨氧化.但是FA本身具有毒性[38],過高濃度的FA也可能直接抑制AOB的生長[44].FA的兩面性使得不同類型的AOB具有不同的最適FA濃度(范圍).而pH值則能夠通過改變NH4+/NH3的電離平衡[12]而影響FA濃度,進(jìn)而影響AOB的生長和代謝:多數(shù)AOB的最適pH值范圍是7~8.5[27],且氨氧化速率隨著pH值的下降而減小[45].表1比較了多株亞硝化單胞菌株的最適FA濃度范圍,其中,多數(shù)菌的最適FA范圍比較狹窄,如sp. AL212[35-36]的最適FA為0.5mg/L,而19718[30]的最適FA范圍也僅為5.9~18.1mg/L.而CZ-4菌在pH=7.3~8.7的范圍內(nèi)均具有較高的氨氧化活性,對(duì)應(yīng)的FA濃度范圍為10.4~196.6mg/L,說明該菌對(duì)FA的親和能力較強(qiáng)但又對(duì)高濃度的FA不甚敏感.目前,僅發(fā)現(xiàn)KYUHI-S[37]具有與CZ-4菌類似的較寬FA適應(yīng)范圍,但二者的16S rDNA序列的差異較大(圖1,二者Blastn的相似度也僅為96%).從應(yīng)用上看,較寬的最適FA范圍不但有利于將CZ-4菌用于處理不同F(xiàn)A濃度的污水,而且有利于降低發(fā)酵生產(chǎn)時(shí)的pH值控制難度.

2.3 對(duì)不同類型污水的脫氨效果

菌劑對(duì)垃圾滲濾液的脫氨效果明顯(圖7):實(shí)驗(yàn)組的氨氮濃度顯著低于對(duì)照組(<0.05),亞硝氮濃度則顯著高于對(duì)照組(<0.05);實(shí)驗(yàn)組的氨氮平均去除速率達(dá)到11.4mg/(L×h),類似的,同期的亞硝氮的平均積累速率也達(dá)到了11.5mg/(L×h),說明脫氨的主要方式為氨氧化(將氨氮氧化為亞硝氮).

圖7 垃圾滲濾液中的氨氧化效果

接種12h后,菌劑對(duì)3個(gè)不同來源的富營養(yǎng)化湖水也有顯著的脫氨效果(圖8a,<0.05):野芷湖水的氨氮濃度從地表水III類標(biāo)準(zhǔn)提高至地表水I類標(biāo)準(zhǔn)(殘余氨氮濃度僅為0.11mg/L),湯遜湖水和南湖水的氨氮濃度也從地表水劣V類標(biāo)準(zhǔn)提高至地表水II類標(biāo)準(zhǔn).類似的,在黑臭水中,按0.1%劑量投加的菌劑也能夠有效脫氨(圖8b,<0.05),特別是氨氮去除速率會(huì)持續(xù)增加:從12~24h時(shí)的0.09mg/(L×h),逐步增加至48~60h時(shí)的0.45mg/(L×h).

根據(jù)亞硝化單胞菌的底物親和力和生長速率的不同,可分為r策略者和k策略者[5,46].其中,r策略者的底物親和力低,生長快,如、.和.等[14];k策略者的底物親和力高,但生長慢,如.和.等[15].鮮見單株亞硝化單胞菌在不同氨氮濃度培養(yǎng)基或污水中均具有較高脫氨活性的報(bào)道.由于缺少將純種亞硝化單胞菌應(yīng)用于污水的報(bào)道,表2比較了前人將亞硝化單胞菌接種至不同初始氨氮濃度的培養(yǎng)基中的平均氨氮去除速率,結(jié)果表明CZ-4菌不但在高氨氮培養(yǎng)基和高氨垃圾滲濾液中具有最高的氨氮去除速率,而且在中低濃度氨氮的地表水中也具有較高的氨氮去除速率,如該菌僅以0.1%的接種比處理初始氨氮濃度僅為15.88mg/L的黑臭河水時(shí)的氨氮去除速率,與.Ms1[33]和.KYUHI-S[37]等菌在按5%~10%比例接種于初始氨氮濃度為100~532mg/L的培養(yǎng)基中的速率相當(dāng)(表2),甚至明顯高于sp. THD-1[47]在氨氮濃度為58mg/L的培養(yǎng)基中的情況.而CZ-4菌對(duì)中低濃度氨氮具有較高親和力的原因則可能與AMO有關(guān):在基因組層面上,盡管多數(shù)AOB僅具有單拷貝的AMO基因,但少數(shù)AOB卻具有多拷貝的AMO基因[15],特別是與CZ-4菌遺傳關(guān)系最接近的C91也具有2個(gè)拷貝的AMO基因[48],而較多的拷貝數(shù)有利于增強(qiáng)AOB的低氨適應(yīng)性[15,49];在表達(dá)調(diào)控的層面上,也有證據(jù)表明,AMO的數(shù)量也會(huì)隨著FA濃度的降低而升高[50],從而增強(qiáng)AOB的低氨適應(yīng)性.

表2 不同亞硝化單胞菌脫氨效果的比較

最短倍增時(shí)間是指示微生物生長的重要指標(biāo),已知的亞硝化單胞菌的最短倍增時(shí)間均不低于8.0h[51-52],而CZ-4菌在培養(yǎng)基中的最短倍增時(shí)間低至8.2h,明顯低于與CZ-4菌遺傳關(guān)系最接近的C91[31]的最短倍增時(shí)間(表2).特別是,CZ-4菌在黑臭水中的最短倍增時(shí)間也僅為10.9h,甚至低于多數(shù)亞硝化單胞菌在合成培養(yǎng)基中的最短倍增時(shí)間(表2).綜上所述,CZ-4菌既對(duì)氨氮具有較高的親和力,又具有較快的生長速度,兼具r策略和k策略的優(yōu)點(diǎn),說明該菌具有重要的應(yīng)用價(jià)值.

3 結(jié)論

3.1 從垃圾滲濾液中分離了一株.CZ-4,其16S rDNA序列與.C91的相似度為99%.

3.2 CZ-4菌的最適生長溫度為30.9℃,最適生長pH值為7.3~8.7;其半數(shù)抑制鹽度約為2%,半數(shù)抑制FNA濃度約為0.11mg/L.發(fā)酵條件優(yōu)化后,最大氨氮去除速率為57.59mg/(L×h),最短倍增時(shí)間為8.2h.

3.3 CZ-4菌能夠有效去除初始氨濃度為0.66~603mg/L的地表水或污水中的氨氮,對(duì)垃圾滲濾液的最大氨氮去除速率為11.4mg/(L×h),在黑臭水中的最短倍增時(shí)間為10.9h.

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Nitrogen removal characteristics of a highly adaptableCZ-4.

XIONG Ying1, XIANG Si1,2, CHENG Kai1*

(1.Hubei Key Laboratory of Ecological Restoration for River-Lakes and Algal Utilization for College of Resources and Environmental Engineering, Hubei University of Technology, Wuhan 430068, China；2.Wuhan Micro-Glory Environmental Technology Innovation Co.Ltd, Wuhan 430068, China)., 2019,39(8)：3365~3372

Astrain was isolated from the landfill leachate. It was named asCZ-4 for its 16s rDNA sequence was highly similar toC91at an identity of 99%. This work studied the influences of pH, temperature, free nitrous acid concentration and salinity on the growth ofCZ-4, as well as its NH3-N removal abilities in landfill leachate, black odor water and eutrophic lake water. The results showed that the optimum growth pH of the strain was 7.3~8.7, the optimum growth temperature was 30.9°C, and the IC50of free nitrous acid and salinity was about 0.11mg/L and 2% (in terms of NaCl), respectively. Under the optimal fermentation condition, the maximum NH3-N removal rate reached 58mg/(L×h), and the shortest doubling time was 8.2h. In different types of sewage/surface water (their initial ammonia concentration ranged from 0.66mg/L to 603mg/L), the NH3-N removal rate was up to 11.4mg/(L×h), the doubling time was as short as 10.9h, and the residual NH3-N concentration was down to 0.11mg/L.

autotrophic ammonia oxidizing bacteria；landfill leachate；；ammonia nitrogen removal rate；doubling time

X172,X703.1

A

1000-6923(2019)08-3365-08

熊 英(1994-),女,湖北孝感人,碩士研究生,主要研究方向?yàn)榘毖趸⑸锛夹g(shù).發(fā)表論文1篇.

2019-01-04

國家科技重大專項(xiàng)(2017ZX07602002)

* 責(zé)任作者, 教授, chengkaicn@163.com