袁建華，趙天濤,2，彭緒亞

?

極端條件下異養(yǎng)硝化-好氧反硝化菌脫氮的研究進(jìn)展

袁建華1，趙天濤1,2，彭緒亞1

1 重慶大學(xué) 城市建設(shè)與環(huán)境工程學(xué)院，重慶 400045 2 重慶理工大學(xué) 化學(xué)化工學(xué)院，重慶 400054

異養(yǎng)硝化-好氧反硝化 (HN-AD) 是對(duì)傳統(tǒng)自養(yǎng)硝化異養(yǎng)反硝化理論的豐富與突破。HN-AD菌在好氧條件下可快速實(shí)現(xiàn)氨氮、硝態(tài)氮 (NO3–-N)、亞硝態(tài)氮 (NO2–-N) 三氮同步脫除。它們不僅具有分布范圍廣、適應(yīng)能力強(qiáng)、代謝通路特殊等特點(diǎn)，而且還具有世代時(shí)間短、脫氮速率快、高活性持久等獨(dú)特優(yōu)勢(shì)，在高鹽、低溫、高氨氮等極端條件表現(xiàn)出了巨大的脫氮潛力，因此在廢水生物脫氮領(lǐng)域受到廣泛關(guān)注。文中在介紹HN-AD菌屬類別及代謝機(jī)理的基礎(chǔ)上，重點(diǎn)總結(jié)了在高鹽、低溫、高氨氮等極端條件下進(jìn)行氨氮脫除的HN-AD種屬，系統(tǒng)分析了它們?cè)跇O端條件下的脫氮特性及潛力，并簡(jiǎn)述了HN-AD菌在極端條件下的工藝應(yīng)用研究進(jìn)展，最后展望了HN-AD脫氮技術(shù)的應(yīng)用前景和研究方向。

異養(yǎng)硝化-好氧反硝化，代謝機(jī)理，極端條件，生物脫氮

氨氮超標(biāo)排放會(huì)導(dǎo)致水體黑臭及富營(yíng)養(yǎng)化，不僅對(duì)魚(yú)類及水生生物產(chǎn)生毒害作用，而且嚴(yán)重危害生態(tài)平衡及人體健康[1]。傳統(tǒng)生物脫氮技術(shù)具有條件溫和、處理成本低、二次污染小等優(yōu)勢(shì)，但隨著污水排放標(biāo)準(zhǔn)提高，傳統(tǒng)生物脫氮技術(shù)已無(wú)法滿足可持續(xù)發(fā)展需求[2-3]。尤其在應(yīng)對(duì)極端條件廢水處理時(shí)，該類技術(shù)暴露出生物活性低、反應(yīng)速度慢、處理效果差等技術(shù)瓶頸[4]。常見(jiàn)極端條件主要包括高鹽、低溫、高氨氮等。高鹽廢水通常是指鹽度超過(guò)1%的廢水，過(guò)高的鹽度會(huì)引起細(xì)胞酶活降低，喪失脫氮功能[5]；低溫條件在我國(guó)比較普遍，很多廢水處理設(shè)施處于高海拔、高緯度的低溫地區(qū)，當(dāng)溫度每降低10 ℃時(shí)，會(huì)導(dǎo)致脫氮微生物的酶促反應(yīng)速率降低1–2倍[6]；高氨氮廢水是指氨氮濃度超過(guò)300 mg/L的廢水，污泥脫水液、厭氧消化液、垃圾濃縮液等都屬于此類廢水。高濃度的游離氨對(duì)硝化菌具有強(qiáng)抑制和高毒害作用，現(xiàn)有工藝多采用投加酸堿等化學(xué)試劑進(jìn)行控制，易造成廢水處理費(fèi)用高昂、二次污染等問(wèn)題[7]。應(yīng)對(duì)這些極端條件，開(kāi)發(fā)經(jīng)濟(jì)高效的新型生物脫氮技術(shù)一直是該領(lǐng)域的研究熱點(diǎn)。

1983年，Robertson等從脫硫脫硝廢水中首次分離得到了異養(yǎng)硝化-好氧反硝化(HN-AD) 菌株泛養(yǎng)副球菌，它主要包括氨單加氧酶(AMO)、羥胺氧化酶(HAO)、硝酸還原酶(NAR) 等功能酶[8]。HN-AD菌屬在好氧條件下可快速將氨氮、硝態(tài)氮(NO3–-N)、亞硝態(tài)氮(NO2–-N) 轉(zhuǎn)化為含氮?dú)怏w，整個(gè)代謝過(guò)程幾乎沒(méi)有NO3–-N和NO2–-N積累[9]。研究者已篩選得到了約20個(gè)屬近100多種具有HN-AD代謝特性的菌株，這些菌株來(lái)源于土壤、污泥、水體以及火山口、鹽堿地等環(huán)境中[10]。隨著對(duì)HN-AD的深入研究，科研人員驚喜地發(fā)現(xiàn)HN-AD菌具有環(huán)境適應(yīng)能力強(qiáng)、污染物耐受濃度高等優(yōu)點(diǎn)。如Lei等得到的臺(tái)灣佐氏DN-7耐受最高氨氮濃度可達(dá)2 000 mg/L[11]；Duan等篩選的嗜鹽弧菌SF16在鹽度為5%時(shí)，對(duì)120 mg/L的氨氮去除率達(dá)到了92.1%，總氮(TN)去除率達(dá)到了73.9%[12]；Yao等分離的不動(dòng)桿菌sp. HA2在溫度低至10 ℃時(shí)，可將80 mg/L的氨氮和TN都100%去除[13]。除此之外，HN-AD菌屬還具有世代時(shí)間短、脫氮速率快、高活性持久等優(yōu)勢(shì)，這使其在極端條件廢水處理領(lǐng)域表現(xiàn)出了巨大的應(yīng)用潛力[14]。這些研究從菌屬種類、脫氮能力及機(jī)理方面對(duì)HN-AD菌的特性進(jìn)行了初步探索，然而關(guān)于HN-AD菌在極端條件下脫氮的關(guān)鍵基因和代謝機(jī)制的解析還不全面，不同極端條件下的菌種投加方式、碳源選取類型、工藝優(yōu)化參數(shù)等尚未完全闡明。系統(tǒng)歸納HN-AD菌屬在極端條件的脫氮進(jìn)展將有助于豐富HN-AD脫氮理論和推進(jìn)HN-AD脫氮工藝的研發(fā)，而目前此類綜述鮮有報(bào)道。

據(jù)此，文中對(duì)極端條件下具有脫氮性能的HN-AD菌屬開(kāi)展廣泛調(diào)研，系統(tǒng)總結(jié)國(guó)內(nèi)外關(guān)于HN-AD菌屬在高鹽、低溫、高氨氮等極端條件脫氮的研究成果，對(duì)比分析不同HN-AD菌屬的耐受程度及脫氮特性；并結(jié)合課題組在HN-AD菌屬篩選及脫氮研究方面的進(jìn)展，考察該類菌屬在極端條件下的應(yīng)用效果；最后對(duì)HN-AD脫氮技術(shù)工程的應(yīng)用前景及研究方向進(jìn)行了展望。以期為HN-AD菌屬進(jìn)行極端條件下廢水氨氮的生物脫除提供理論依據(jù)和技術(shù)支撐。

1 HN-AD菌屬及代謝特性

自1983年Robertson等首次分離得到了異養(yǎng)硝化-好氧反硝化(HN-AD) 菌株[8](曾用名)以來(lái)，目前，約20多個(gè)屬的HN-AD菌株被分離出來(lái)，主要有產(chǎn)堿菌屬、假單胞菌屬、芽孢桿菌屬、不動(dòng)桿菌屬等。表1對(duì)近十年不同種屬菌株的來(lái)源、碳源、碳氮比(C/N) 等進(jìn)行了總結(jié)。歸納菌株的來(lái)源，發(fā)現(xiàn)HN-AD菌除了存在于土壤、污泥、廢水中，還存在于火山巖漿、鹽堿濕地、低溫凍土等極端環(huán)境中[10]，由此表明HN-AD菌不僅分布廣泛，而且對(duì)極端環(huán)境具有耐受能力；分析所需的碳源，可知HN-AD菌屬能快速利用葡萄糖和蔗糖等易吸收的糖類碳源，也能利用檸檬酸鈉、琥珀酸鈉、丁二酸鈉等非糖類碳源?？傮w上，不同種屬的HN-AD菌對(duì)碳源呈現(xiàn)出一定的選擇性[15]；對(duì)于C/N，HN-AD菌屬的適應(yīng)范圍較寬，通常在6–20之間，多數(shù)菌株需求的C/N在10左右，少數(shù)菌株能耐受C/N≤5的貧營(yíng)養(yǎng)條件[16]。

研究者不但開(kāi)展了大量HN-AD菌種的分離工作，而且對(duì)HN-AD的關(guān)鍵酶和代謝特性也進(jìn)行了深入研究。1998年Richardson 等[17]發(fā)現(xiàn)HN-AD脫氮過(guò)程的關(guān)鍵酶主要包括氨單加氧酶(AMO)、羥胺氧化酶(HAO)、周質(zhì)硝酸鹽還原酶(NAP)、亞硝酸還原酶(NIR)、一氧化氮還原酶(NOR) 和一氧化二氮還原酶(NOS)，接著又提出了目前國(guó)內(nèi)外公認(rèn)的脫氮代謝途徑，如圖1所示，首先氨在AMO的作用下氧化生成羥胺，然后羥胺在HAO的作用下生成亞硝酸鹽，最后亞硝酸鹽或硝酸鹽在NIR、NOR、NOS的還原作用下分別生成NO、N2O和N2，整個(gè)脫氮過(guò)程基本沒(méi)有NO3–-N和NO2–-N的積累。

表1 典型HN-AD菌及其脫氮特性

圖1 HN-AD脫氮代謝途徑[17]

隨后，許多學(xué)者對(duì)HN-AD提出了不同的代謝模型，其中以Wehrfritz等[18]提出的偶聯(lián)模型最具代表性。如圖2所示，該模型以亞硝酸鹽作為硝化反硝化偶聯(lián)的分節(jié)點(diǎn)，異養(yǎng)硝化時(shí)羥胺被氧化為NO2–，所產(chǎn)生的電子直接傳遞給反硝化酶系的電子供體細(xì)胞色素c550，通過(guò)細(xì)胞色素c550先將電子傳遞給NIR、NOR、NOS，最后將電子傳遞給細(xì)胞色素aa3氧化酶將氧還原為水。異養(yǎng)硝化是指微生物利用有機(jī)物作為碳源同時(shí)將氨氮轉(zhuǎn)化為羥胺、亞硝態(tài)氮、硝態(tài)氮等；好氧反硝化是指微生物在有氧氣和碳源存在的條件下，利用O2和NO2–-N等作為電子受體進(jìn)行的呼吸作用。HN-AD菌屬特殊的代謝通路實(shí)現(xiàn)了硝化和反硝化在異養(yǎng)和好氧的條件下同時(shí)發(fā)生，打破了傳統(tǒng)硝化反硝化必須分隔以及反硝化必須在缺氧條件下進(jìn)行的限制，是對(duì)傳統(tǒng)硝化反硝化理論的豐富和突破[19]。

總體上，HN-AD菌表現(xiàn)出了分布范圍廣、適應(yīng)能力強(qiáng)、代謝通路特殊等特點(diǎn)。深入調(diào)研發(fā)現(xiàn)HN-AD菌屬還具有世代時(shí)間短、脫氮速率快、高活性持久等獨(dú)特優(yōu)勢(shì)，這使其在應(yīng)對(duì)極端條件時(shí)具備了較高的耐受性，文中從高鹽、低溫、高氨氮等方面對(duì)耐受極端條件的HN-AD菌屬進(jìn)行了總結(jié)。

圖2 HN-AD偶聯(lián)機(jī)理模型[18]

2 極端環(huán)境HN-AD菌屬脫氮研究現(xiàn)狀

2.1 高鹽環(huán)境下HN-AD脫氮

高鹽廢水一般是指總含鹽量大于1%的廢水，含有較高濃度的Cl–、SO42–、Na+、Ca2+等無(wú)機(jī)離子[38]。高鹽廢水來(lái)源廣泛，主要包括印染、腌制、造紙等化工生產(chǎn)以及海水直接利用過(guò)程產(chǎn)生的廢水[39]。我國(guó)高鹽廢水總量巨大，約占廢水總量的5%，并每年以2%的速率增長(zhǎng)[5]。生物法開(kāi)始逐漸應(yīng)用于高鹽含氮廢水處理，然而普通微生物處理高鹽廢水時(shí)由于鹽度過(guò)高一直存在處理系統(tǒng)菌群數(shù)量減少、有機(jī)物和氨氮去除率降低、出水懸浮物濃度大等諸多問(wèn)題[40-41]，所以篩選耐鹽、嗜鹽的脫氮功能微生物逐漸成為高鹽含氮廢水處理領(lǐng)域研究的熱點(diǎn)。

研究者在分離耐鹽、嗜鹽脫氮功能微生物的過(guò)程中，發(fā)現(xiàn)許多HN-AD菌同時(shí)表現(xiàn)出了耐鹽和脫氮的性能。如Duan等[12]從海洋沉積物中篩選出一株嗜鹽弧菌SF16在鹽度為5%、氨氮濃度為120 mg/L的條件下，培養(yǎng)48 h后氨氮去除率達(dá)到了92.1%，TN去除率達(dá)到了73.9%；Chen等[23]研究的嗜水氣單胞菌sp. HN-02在鹽度為2%的條件下仍表現(xiàn)出較強(qiáng)的氨氮和TN去除能力，氨氮平均去除速率達(dá)30 mg/(L·h)，24 h內(nèi)TN去除率達(dá)到了80.8%，且1%的鹽度對(duì)氨氮的去除基本沒(méi)有影響；曲洋等[42]分離的假單胞菌qy18和鹽單胞菌gs2的適宜生長(zhǎng)鹽度范圍分別為0–4%和2%–10%，在48 h內(nèi)菌株qy18和菌株gs2的氨氮去除率分別為98.5%和96.1%，TN去除率分別達(dá)到了83.6%和81.5%，最大氨氮去除速率分別為5.8 mg/(L·h) 和5.5 mg/(L·h)，兩株菌在高鹽度條件下可同時(shí)利用有機(jī)碳源和氨氮為底物進(jìn)行硝化反應(yīng)和同步脫氮。

根據(jù)不同菌屬的耐鹽能力差異，目前將耐受鹽度小于3%的細(xì)菌定義為耐鹽菌，在3%–15%之間的細(xì)菌稱為中度嗜鹽菌，大于15%的細(xì)菌稱為極端嗜鹽菌[43]，表2根據(jù)HN-AD菌屬的耐鹽能力對(duì)其進(jìn)行了分類。由表2可知，耐鹽HN-AD菌屬主要來(lái)源于海洋、鹽場(chǎng)底泥、腌制廢水等含鹽環(huán)境，其耐鹽和脫氮能力受分離場(chǎng)地影響較大，如從排污淤泥中篩選的施氏假單胞菌A-13耐受的鹽濃度達(dá)到了10%，且對(duì)初始濃度分別為620 mg/L、570 mg/L、545 mg/L的NO3–-N、NO2–-N、氨氮去除率分別達(dá)到了99.7%、90.7%和67.7%，最高TN去除率達(dá)到了80.8%[44]，而從生活廢水中獲得的甲養(yǎng)芽孢桿菌L7耐鹽濃度僅為3.5%，最大氨氮去除率為83.4%，最大NO2–-N去除速率為5.81 mg/(L·d)[45]。HN-AD菌的耐鹽濃度范圍通常在5%–10%之間，屬于中度嗜鹽菌，某些特殊菌種能耐受超過(guò)10%的鹽度，如鹽田鹽單胞菌ha3[46]，能夠耐受20%的高鹽度，其最大NO3–-N去除速率達(dá)到了87.5 mg/(L·h)，與其他HN-AD菌株不同，它的最適pH為9.0，除了嗜鹽，還表現(xiàn)出一定的嗜堿性。HN-AD菌屬耐鹽脫氮的特性，克服了高鹽對(duì)傳統(tǒng)生物處理過(guò)程的限制，同時(shí)解決了傳統(tǒng)微生物耐鹽不脫氮、脫氮不耐鹽的矛盾[47]，未來(lái)在海鮮加工、水產(chǎn)養(yǎng)殖、腌制等高鹽廢水脫氮處理方面具有較大的應(yīng)用價(jià)值。

表2 具有耐鹽性能的HN-AD菌

2.2 低溫條件下HN-AD脫氮

常規(guī)脫氮菌株的最適溫度范圍為28–37 ℃，當(dāng)溫度每降低10℃，脫氮微生物的總量和酶活均受到嚴(yán)重影響，污染物降解效率降低1–2倍[6]。為了解決常規(guī)脫氮微生物無(wú)法耐受低溫這一難題，分離在低溫條件下具有高效脫氮功能的菌株越發(fā)受到研究與工程技術(shù)人員的關(guān)注[51-52]。

近年來(lái)，HN-AD菌屬在低溫條件下的脫氮潛能逐漸被挖掘。表3根據(jù)耐低溫程度對(duì)脫氮HN-AD菌株進(jìn)行了總結(jié)。HN-AD菌屬耐受低溫的范圍為2–15 ℃，其中耐受5–10℃的菌株較多，它們?cè)诘蜏貤l件下仍保持了較高的脫氮速率。如Yao等[13]篩選的不動(dòng)桿菌sp. HA2在10 ℃下，氨氮脫除速率可達(dá)到3 mg/(L·h)，TN去除率達(dá)到了100%；惡臭假單胞菌Y-12[53]在15 ℃時(shí)，4 d后能將初始氨氮濃度為208.1 mg/L脫除到2.4 mg/L，氨氮去除率達(dá)到98.8%，TN去除率平均達(dá)到75.5% 以上；擬南芥假單胞菌AN-1[54]在10 ℃時(shí)，氨氮、NO3–-N、NO2–-N脫除效率分別可達(dá)到1.6 mg/(L·h)、1.5 mg/(L·h)和0.69 mg/(L·h)；從松花江分離的微桿菌屬sp. SFA13在溫度為5 ℃、初始氨氮濃度為61.6 mg/L時(shí)，氨氮和NO3–-N的脫除速率最高分別達(dá)到了1.6 mg/(L·h)和0.24 mg/(L·h)[55]。課題組分離的HN-AD菌株TAC-1，在5 ℃的低溫條件下、能將濃度為400 mg/L的氨氮快速脫除，去除速率達(dá)到了3.7 mg/(L·h)，同時(shí)TN去除率達(dá)到了79.5%。歸納發(fā)現(xiàn)耐冷HN-AD菌屬在5–10 ℃時(shí)，氨氮平均脫除速率為2–3 mg/(L·h)，在10–15 ℃時(shí)通常為4–6 mg/(L·h)，可見(jiàn)HN-AD菌屬在低溫條件下的脫氮速率在一定范圍內(nèi)隨溫度的升高而升高?？傮w而言，這些耐冷HN-AD菌株不僅在低溫條件下進(jìn)行正常的生長(zhǎng)代謝，而且實(shí)現(xiàn)了氨氮和總氮的高效脫除，足以體現(xiàn)其具有應(yīng)用于低溫廢水脫氮的潛能。

為了適應(yīng)低溫環(huán)境，耐冷微生物通常會(huì)通過(guò)改變脂類組成來(lái)調(diào)節(jié)膜的流動(dòng)性以適應(yīng)溫度變化，同時(shí)，它們還會(huì)生成冷休克蛋白和冷適應(yīng)酶來(lái)應(yīng)對(duì)低溫環(huán)境[56]；與傳統(tǒng)分子機(jī)制不同的是，HN-AD菌在低溫條件下還會(huì)產(chǎn)生較多的抗氧化酶以保護(hù)機(jī)體免受超氧陰離子、過(guò)氧化氫、OH自由基造成的損傷[57]；大多數(shù)HN-AD菌對(duì)C/N的需求較高，多數(shù)菌株需求的C/N在10左右。在高濃度有機(jī)碳環(huán)境下，菌體自身好氧代謝會(huì)大量產(chǎn)熱，熱量一部分用于細(xì)胞合成和代謝，多余部分則以熱的形式散發(fā)，其表現(xiàn)在宏觀上使得外界溫度升高[58-59]；此外，當(dāng)外界溫度較低時(shí)，活性污泥和生物膜會(huì)調(diào)整自身的代謝產(chǎn)熱系統(tǒng)，在相應(yīng)減少細(xì)胞合成的同時(shí)，將大量ATP轉(zhuǎn)化為熱量，用于平衡和調(diào)節(jié)胞內(nèi)和外界溫度，以此相對(duì)提升自身的低溫適應(yīng)能力[60]?，F(xiàn)有研究表明HN-AD菌屬具有獨(dú)特的耐冷機(jī)制，但基于HN-AD菌屬細(xì)胞水平和基因水平的耐冷機(jī)制研究還較少，詳細(xì)的代謝機(jī)理和關(guān)鍵基因還有待進(jìn)一步確定。

表3 低溫條件下脫氮的HN-AD菌

2.3 高氨氮條件下HN-AD脫氮

目前，國(guó)內(nèi)外處理高氨氮廢水的主要方法分為物化法、生物法、物化-生物聯(lián)合法，對(duì)于污泥脫水液、厭氧消化液、焦化廢液等可生化性差、氨氮濃度極高的廢水，通常采用折點(diǎn)加氯、氣提吹脫和離子交換等物化法進(jìn)行處理[65]；對(duì)于氨氮濃度在500–1 500 mg/L左右的廢水，常采用物化-生物等多工藝聯(lián)合進(jìn)行處理，但物化法作為前端處理此類廢水時(shí)普遍存在運(yùn)行費(fèi)用昂貴的缺點(diǎn)。傳統(tǒng)生物脫氮技術(shù)易受游離氨影響，處理廢水的氨氮濃度不宜超過(guò)300 mg/L，雖然游離氨的控制技術(shù)已比較成熟，但脫氮過(guò)程中大量堿度的消耗及曝氣等電耗同樣導(dǎo)致處理成本高昂，所以目前利用傳統(tǒng)微生物進(jìn)行高氨氮廢水的處理仍然存在瓶頸[66-67]。因此，篩選對(duì)高氨氮具有耐受和脫除能力的功能微生物是未來(lái)處理此類廢水的研究方向[68]。

HN-AD菌屬能夠在好氧和高C/N條件下快速脫氮，一方面是因?yàn)轶w系中充足的氧氣及時(shí)補(bǔ)充了脫氮所需的電子受體；另一方面，高C/N保證了消耗堿度的及時(shí)補(bǔ)充，為脫氮提供了穩(wěn)定的條件。HN-AD菌的這些生長(zhǎng)特性使其在耐受高氨氮方面展現(xiàn)出了獨(dú)特的優(yōu)勢(shì)[10]。表4對(duì)可耐受和脫除高氨氮的HN-AD菌屬進(jìn)行了總結(jié)。如叢毛單胞菌WXZ-17[69]可耐受初始濃度為817 mg/L的氨氮，氨氮和TN去除率分別達(dá)到了36.1%和26.3%；Shoda等[70]利用菌株產(chǎn)堿桿菌No.4去除初始氨氮濃度約1 000 mg/L的硝化污泥，24 h內(nèi)氨氮可徹底去除，平均氨氮去除速率達(dá)到了121 mg/(L·h)，反硝化率達(dá)到了76.2%。對(duì)比可發(fā)現(xiàn)，不同種屬的HN-AD菌株對(duì)氨氮的耐受程度及脫氮效果不同，如從活性污泥中篩選的鐮刀菌sp. A60[71]可耐受的初始氨氮濃度為800 mg/L，氨氮和TN去除率分別達(dá)到92%和88.4%，而從活性污泥中分離的不動(dòng)桿菌sp. Y1[72]耐受的初始氨氮濃度卻能達(dá)到1 600 mg/L，同時(shí)對(duì)初始濃度為108.2 mg/L的氨氮去除率達(dá)到了98.8%，TN去除率達(dá)到了90.9%。此外，同屬不同種的HN-AD菌的氨氮和TN脫除能力也存在差異，如不動(dòng)桿菌spTN-14[73]和不動(dòng)桿菌spSQ2[74]處理初始濃度約為600 mg/L的氨氮時(shí)，氨氮去除率分別為65.7%和97.8%，TN去除率分別為64.8%和73.2%。

通過(guò)對(duì)HN-AD菌屬耐受高氨氮機(jī)制的解析，發(fā)現(xiàn)上述菌株具備高氨氮脫除的特性與其代謝通路和生存環(huán)境具有密切關(guān)系。一方面，HN-AD菌屬可實(shí)現(xiàn)氨氮、NO3–-N、NO2–-N三氮的同步脫除，不僅縮短了脫氮周期，而且降低了NO2–-N積累對(duì)菌體產(chǎn)生的毒害作用[9]；另一方面，HN-AD菌屬屬于異養(yǎng)需氧型微生物，氧氣和基質(zhì)的供應(yīng)不僅加速了細(xì)胞的增殖分化，使其快速將氨氮同化為細(xì)胞成分，而且使細(xì)胞保持了較高的脫氮酶活性，從酶活層面加速了高氨氮的脫除[75]。

表4 脫除高濃度氨氮的HN-AD菌

2.4 其他極端環(huán)境下HN-AD的脫氮研究

HN-AD菌除了能耐受高鹽、低溫、高濃度氨氮等極端條件，還能耐受貧營(yíng)養(yǎng)、過(guò)量重金屬、強(qiáng)堿等其他極端條件。如Su等[78]篩選的不動(dòng)桿菌sp. SYF26在C/N為4.5時(shí)，氨氮去除率可達(dá)到93.6%；動(dòng)膠菌屬sp. N299在C/N為1.1的條件下，TN去除率可達(dá)到46.4%[79]。C/N決定了反硝化電子供體的豐富度，在低C/N比條件下，普通脫氮菌株因?yàn)轶w系電子供體不足，脫氮速率通常不同程度降低，而部分HN-AD菌株在電子供體不足的條件下仍能保持較好的脫氮活性，充分展現(xiàn)了其耐受貧營(yíng)養(yǎng)的優(yōu)勢(shì)，未來(lái)將有望應(yīng)用于地下水污水、水庫(kù)水源污染等微污染水源的治理[80-81]。重金屬元素是微生物生長(zhǎng)活動(dòng)代謝過(guò)程中必不可少的微量元素，微量金屬離子對(duì)微生物的酶活具有一定的促進(jìn)作用，但過(guò)量的重金屬對(duì)微生物具有毒性[82]。研究發(fā)現(xiàn)一些HN-AD菌屬對(duì)過(guò)量重金屬也表現(xiàn)出了耐受能力，如王瑤等[83]發(fā)現(xiàn)糞產(chǎn)堿桿菌C16能夠耐受≥22.4 mg/L的Fe2+；He等[84]分離的銅綠假單胞菌PCN-2在好氧條件下能同步還原硝酸鹽和5 mg/L的Cr6+。利用微生物對(duì)重金屬的吸附和積累作用，可以超量吸收轉(zhuǎn)移一種或幾種重金屬，從而達(dá)到減少環(huán)境中重金屬含量的目的，因此，后續(xù)有必要繼續(xù)開(kāi)展HN-AD菌株對(duì)重金屬的吸附和積累研究。此外，少數(shù)HN-AD菌株還可在強(qiáng)堿環(huán)境下保持活性，如假單胞菌ZPQ2[85]的最適pH為11，表現(xiàn)出明顯的嗜堿性，傳統(tǒng)自養(yǎng)硝化菌的最適pH為6–8，相較而言，HN-AD菌株具有更加寬泛的pH適應(yīng)范圍[86]。HN-AD菌屬在這些極端條件仍能發(fā)揮其脫氮功能，這為極端條件下的廢水處理提供了新渠道，也極大地拓寬了HN-AD技術(shù)的應(yīng)用范圍。

3 極端條件下HN-AD的工藝研究

HN-AD菌屬在極端條件下表現(xiàn)出的脫氮潛力使得越來(lái)越多的學(xué)者開(kāi)始進(jìn)行相關(guān)菌株的工藝研究。目前工藝研究的主要方式包括與反應(yīng)器結(jié)合、菌株固定化、直接投加于處理系統(tǒng)中等，研究者主要通過(guò)簡(jiǎn)化工藝流程、控制工藝條件、優(yōu)化工藝過(guò)程等來(lái)提高脫氮效率。當(dāng)前極端條件的工藝研究實(shí)例主要集中在低溫、高溫、高鹽、高氨氮等。如在低溫條件下，Yao等[13]為了解決低溫條件下污水處理廠脫氮效率低等問(wèn)題，將耐寒的HN-AD菌群投加到反應(yīng)器中進(jìn)行生物強(qiáng)化，并通過(guò)逐漸增加溶解氧濃度，結(jié)果不僅縮短了硝化時(shí)間，而且成功提高了低溫(10 ℃)條件下污水氨氮的去除效率；在高溫條件下，楊云龍[87]等將曝氣生物濾池與螯臺(tái)球菌TAD1相結(jié)合，考察了菌株在高溫下的HN-AD性能，脫氮過(guò)程中控制濾池溫度為50 ℃，同時(shí)優(yōu)化了溶解氧參數(shù)，當(dāng)以硫酸銨和硝酸鈉分別為唯一氮源時(shí)，菌株的氨氮和TN去除率在12 h內(nèi)均達(dá)到了100%。又如在高鹽條件下，蘇兵[12]將嗜鹽HN-AD菌株SF16用于牡蠣殼填料曝氣生物濾池，控制鹽度為3%、C/N為10、pH為7.5–9.5、氨氮濃度為28.1–35.1 mg/L時(shí)，氨氮去除率達(dá)到了97.1%，TN去除率達(dá)到了73.92%；在高氨氮條件下，Joo[88]利用糞產(chǎn)堿桿菌No.4處理氨氮濃度為2 000 mg/L的豬場(chǎng)廢水，最大氨氮脫除速率達(dá)到了30 mg/(L·h)；課題組將前期分離的HN-AD菌株TAC-1以10%的接種量投加于單級(jí)三維結(jié)構(gòu)生物轉(zhuǎn)盤(pán)(3D-RBC)，控制轉(zhuǎn)速為34 r/min、水力停留時(shí)間(HRT) 為24 h、進(jìn)水化學(xué)需氧量 (Chemical oxygen demand，COD) 為5 000 mg/L、氨氮濃度為500 mg/L時(shí)，氨氮、總氮、COD的去除率分別達(dá)到了99.4%、79.5%、85.2%，研究結(jié)果也證實(shí)了HN-AD菌株進(jìn)行工藝研究時(shí)具有同步脫除高氨氮和COD的效果。HN-AD菌株的工藝研究是未來(lái)開(kāi)發(fā)HN-AD生物脫氮技術(shù)的必經(jīng)之路，能為以后開(kāi)發(fā)生物脫氮工藝提供重要的理論參數(shù)和實(shí)踐經(jīng)驗(yàn)。

4 總結(jié)與展望

近20年來(lái)，關(guān)于HN-AD菌屬的研究取得了許多實(shí)質(zhì)性的進(jìn)展，不僅加深了HN-AD菌屬脫氮機(jī)理和脫氮特性的認(rèn)識(shí)，而且挖掘了其在極端條件下的脫氮潛力。目前，約20多個(gè)屬的HN-AD菌株被分離出來(lái)，一方面，研究者對(duì)其進(jìn)行了生長(zhǎng)特性、脫氮效果及代謝機(jī)理等方面的深入研究，發(fā)現(xiàn)HN-AD菌除了能耐受高鹽、低溫、高濃度氨氮等極端條件，還能耐受貧營(yíng)養(yǎng)、過(guò)量重金屬、強(qiáng)堿等其他極端條件。HN-AD菌屬在這些極端條件仍能發(fā)揮其脫氮功能，為極端條件下廢水的生物脫氮提供了新途徑；另一方面，越來(lái)越多的學(xué)者開(kāi)始了極端條件下菌株的工藝研究，主要方式包括結(jié)合反應(yīng)器、菌株固定化、復(fù)配脫氮菌劑等，一定程度上拓寬了HN-AD菌的研究范圍[8-10]。HN-AD菌屬具有生長(zhǎng)繁殖快、世代時(shí)間短、脫氮效率高等優(yōu)點(diǎn)，這使其在極端條件廢水處理方面具有廣闊的應(yīng)用前景，有望攻克傳統(tǒng)處理工藝無(wú)法兼顧處理效率與經(jīng)濟(jì)適用兩方面的瓶頸[15]。

未來(lái)，HN-AD菌的研究將主要圍繞好氧脫氮技術(shù)如何服務(wù)工程應(yīng)用而展開(kāi)，可能的拓展領(lǐng)域包括以下幾方面：1) 系統(tǒng)開(kāi)展基于培養(yǎng)基優(yōu)化的菌劑發(fā)酵工藝研究，分離篩選在貧營(yíng)養(yǎng)條件具有高脫氮活性的HN-AD菌株；2) 充分利用多組學(xué)測(cè)序技術(shù)，全面解析HN-AD菌屬的特征酶以及功能基因，進(jìn)一步明晰HN-AD菌種同步脫氮的機(jī)理；3) 深入研究HN-AD菌與其他脫氮微生物存在的競(jìng)爭(zhēng)和融合關(guān)系，辨識(shí)不同種屬間的互利共生作用，篩選適于工程應(yīng)用的HN-AD功能菌劑；4) 基于現(xiàn)有在單一極端條件下的研究成果，開(kāi)展HN-AD菌同時(shí)在多種極端環(huán)境下的脫氮研究，并拓展其在生物除磷中的應(yīng)用。

[1] Zhang L, Xu EG, Li YB, et al. Ecological risks posed by ammonia nitrogen (AN) and un-ionized ammonia (NH3) in seven major river systems of China. Chemosphere, 2018, 202: 136–144.

[2] Cai J, Zheng P. Simultaneous removal of sulfide and nitrite by anaerobic bioprocess. Chin J Biotech, 2009, 25(11): 1684–1689 (in Chinese). 蔡靖, 鄭平. 亞硝酸鹽型同步厭氧生物脫氮除硫工藝的運(yùn)行性能. 生物工程學(xué)報(bào), 2009, 25(11): 1684–1689.

[3] Zhang ZZ, Ji YX, Chen H, et al. Application and obstacles of ANAMMOX process. Chin J Biotech, 2014, 30(12): 1804–1816 (in Chinese).張正哲, 姬玉欣, 陳輝, 等. 厭氧氨氧化工藝的應(yīng)用現(xiàn)狀和問(wèn)題. 生物工程學(xué)報(bào), 2014, 30(12): 1804–1816.

[4] Vincent WF. Enigmatic microorganisms and life in extreme environments. J Palaeolimnol, 2002, 27(2): 285–286.

[5] Glass C, Silverstein J. Denitrification of high-nitrate, high-salinity wastewater. Water Res, 1999, 33(1): 223–229.

[6] Morling S, Plaza E. Biological nitrogen removal at low water temperatures-long term experience. Desalinat Water Treat, 2011, 25(1/3): 226–232.

[7] Zhao B, Tian M, An Q, et al. Characteristics of a heterotrophic nitrogen removal bacterium and its potential application on treatment of ammonium-rich wastewater. Bioresour Technol, 2016, 226: 46–54.

[8] Yang T, Yang Y, Liu YX. Research progress and challenges of heterotrophic nitrification-aerobic denitrification. Mocrobiol China, 2017, 44(9): 2213–2222 (in Chinese).楊婷, 楊婭, 劉玉香. 異養(yǎng)硝化-好氧反硝化的研究進(jìn)展. 微生物學(xué)通報(bào), 2017, 44(9): 2213–2222.

[9] Castignetii D, Hollocher TC. Heterotrophic nitrification among denitrifiers. Appl Environ Microbiol, 1984, 47(4): 620–623.

[10] He H, Yu X, Han YT, et al. Research progress in the denitrification characteristics of heterotrophic nitrification-aerobic denitrification bacteria. Ind Water Treat, 2017, 37(4): 12–17 (in Chinese).何環(huán), 余萱, 韓亞濤, 等. 異養(yǎng)硝化好氧反硝化菌脫氮特性的研究進(jìn)展. 工業(yè)水處理, 2017, 37(4): 12–17.

[11] Lei Y, Wang YQ, Liu HJ, et al. A novel heterotrophic nitrifying and aerobic denitrifying bacterium,s DN-7, can remove high-strength ammonium. Appl Microbiol Biot, 2016, 100(9): 4219–4229.

[12] Duan JM, Fang HD, Su B, et al. Characterization of a halophilic heterotrophic nitrification-aerobic denitrification bacterium and its application on treatment of saline wastewater. Bioresour Technol, 2015, 179: 421–428.

[13] Yao S, Ni JR, Chen Q, et al. Enrichment and characterization of a bacteria consortium capable of heterotrophic nitrification and aerobic denitrification at low temperature. Bioresour Technol, 2013, 127: 151–157.

[14] Littleton HX, Daigger GT, Strom PF, et al. Simultaneous biological nutrient removal: evaluation of autotrophic denitrification, heterotrophic nitrification, and biological phosphorus removal in full-scale systems. Water Environ Res, 2003, 75(2): 138–150.

[15] Weng ZH, Lv H, Zhou JT. Research progress in the denitrification performances of heterotrophic nitrifying-aerobic denitrifying bacteria. Ind Water Treat, 2017, 37(3): 21–25 (in Chinese).翁梓航, 呂紅, 周集體. 異養(yǎng)硝化-好氧反硝化菌的脫氮性能研究進(jìn)展. 工業(yè)水處理, 2017, 37(3): 21–25.

[16] Su WY, Gao JF, Zhao HM. Research progress in heterotrophic nitrification-aerobic denitrification bacteria. Ind Water Treat, 2013, 33(12): 1–5 (in Chinese). 蘇婉昀, 高俊發(fā), 趙紅梅. 異養(yǎng)硝化-好氧反硝化菌的研究進(jìn)展. 工業(yè)水處理, 2013, 33(12): 1–5.

[17] He X, Lv J, He YJ, et al. Study progress on the mechanism of heterotrophic nitrification. Acta Microbiol Sin, 2006, 46(5): 844–847 (in Chinese).何霞, 呂劍, 何義亮, 等. 異養(yǎng)硝化機(jī)理的研究進(jìn)展. 微生物學(xué)報(bào), 2006, 46(5): 844–847.

[18] Wehrfritz JM, Reilly A, Spiro S, et al. Purification of hydroxylamine oxidase from. FEBS Lett, 1993, 335(2): 246–250.

[19] Ji B, Yang K, Zhu L, et al. Aerobic denitrification: A review of important advances of the last 30 years. Biotechnol Bioproc Eng, 2015, 20(4): 643–651.

[20] Sun XM, Li QF, Zhang Y, et al. Phylogenetic analysis and nitrogen removal characteristics of a heterotrophic nitrifying-aerobic denitrifying bacteria strain from marine environment. Acta Microbiol Sin, 2012, 52(6): 687–695 (in Chinese).孫雪梅, 李秋芬, 張艷, 等. 一株海水異養(yǎng)硝化-好氧反硝化菌系統(tǒng)發(fā)育及脫氮特性. 微生物學(xué)報(bào), 2012, 52(6): 687–695.

[21] Si WG, Lv ZG, Xu C. Isolation of heterotrophic nitrifiers which can tolerate high concentration of ammonia-nitrogen and the optimization of their nitrogen removal efficiency in wastewater. Environ Sci, 2011, 32(11): 3448–3454 (in Chinese).司文攻, 呂志剛, 許超. 耐受高濃度氨氮異養(yǎng)硝化菌的篩選及其脫氮條件優(yōu)化. 環(huán)境科學(xué), 2011, 32(11): 3448–3454.

[22] Chen PZ, Li J, Li QX, et al. Simultaneous heterotrophic nitrification and aerobic denitrification by bacteriumsp.CPZ24. Bioresour Technol, 2012, 116: 266–270.

[23] Hen MX, Wang WC, Feng Y, et al. Impact resistance of different factors on ammonia removal by heterotrophic nitrification-aerobic denitrification bacteriumsp.HN-02. Bioresour Technol, 2014, 167: 456–461.

[24] Zhao B, An Q, He YL, et al. N2O and N2production during heterotrophic nitrification bystrain NR. Bioresour Technol, 2012, 116: 379–385.

[25] Liu JF, Zhou T, Liu ZH, et al. Screening and identification of a new heterotrophic nitrifying bacteria and characterization of nitrification. Environ Sci Technol, 2014, 37(8): 99–103 (in Chinese).劉杰鳳, 周天, 劉正輝, 等. 一株新型異養(yǎng)硝化細(xì)菌的分離鑒定及硝化特性. 環(huán)境科學(xué)與技術(shù), 2014, 37(8): 99–103.

[26] Zhang JB, Wu PX, Hao B, et al. Heterotrophic nitrification and aerobic denitrification by the bacteriumYZN-001. Bioresour Technol, 2011, 102(21): 9866–9869.

[27] Li CE, Yang JS, Wang X, et al. Removal of nitrogen by heterotrophic nitrification-aerobic denitrification of a phosphate accumulating bacteriumYG-24. Bioresour Technol, 2015, 182: 18–25.

[28] Jin R, Liu T, Liu G, et al. Simultaneous heterotrophic nitrification and aerobic denitrification by the marine origin bacteriumsp.ADN-42. Appl Biochem Biotechnol, 2015, 175(4): 2000–2011.

[29] Huang XF, Li WG, Zhang DY, et al. Ammonium removal by a novel oligotrophicsp.Y16 capable of heterotrophic nitrification-aerobic denitrification at low temperature. Bioresour Technol, 2013, 146: 44–50.

[30] Huang TL, He XX, Zhang HH, et al. Nitrogen removal characteristics of the heterotrophic nitrification-aerobic denitrification bacteriumsp.Sxf14. Appl Microbiol Biot, 2015, 21(2): 201–207.

[31] Ren YX, Yang L, Liang X. The characteristics of a novel heterotrophic nitrifying and aerobic denitrifying bacterium,YB. Bioresour Technol, 2014, 171: 1–9.

[32] Xin YF, Qu XH, Yuan MD, et al. Isolation and identification of a heterotrophic nitrifying and aerobic denitrifyingsp.YF14 and its denitrification activity. Acta Microbiol Sin, 2011, 51(12): 1646–1654 (in Chinese).辛玉峰, 曲曉華, 袁夢(mèng)冬, 等. 一株異養(yǎng)硝化-反硝化不動(dòng)桿菌的分離鑒定及脫氮活性. 微生物學(xué)報(bào), 2011, 51(12): 1646–1654.

[33] Huang TL, Zhang LN, Zhang HH, et al. Screening and nitrogen removal characteristics of a heterotrophic nitrification-aerobic denitrification strain. Ecol Environ Sci, 2015, 24(1): 113–120 (in Chinese).黃廷林, 張麗娜, 張海涵, 等. 一株貧營(yíng)養(yǎng)異養(yǎng)硝化-好氧反硝化菌的篩選及脫氮特性. 生態(tài)環(huán)境學(xué)報(bào), 2015, 24(1): 113–120.

[34] Padhi SK, Tripathy S, Sen R, et al. Characterisation of heterotrophic nitrifying and aerobic denitrifyingCF-S9 strain for bioremediation of wastewater. Int Biodeter Biodegr, 2013, 78: 67–73.

[35] Chen Q, Ni JR. Ammonium removal bysp.LAD9 capable of heterotrophic nitrification-aerobic denitrification. J Biosci Bioeng, 2012, 113(5): 619–623.

[36] Thite VS, Nerurkar AS. Physicochemical characterization of pectinase activity fromsp. and their accessory role in synergism with crude xylanase and commercial cellulase in enzyme cocktail mediated saccharification of agrowaste biomass. J Appl Microbiol, 2018, 124(5): 1147–1163.

[37] Sun ZY, Lv YK, Liu YX, et al. Removal of nitrogen by heterotrophic nitrification-aerobic denitrification of a novel metal resistant bacteriumsp. S1. Bioresour Technol, 2016, 220: 142–150.

[38] Lee KY, Kim KW, Park M, et al. Novel application of nanozeolite for radioactive cesium removal from high-salt wastewater. Water Res, 2016, 95: 134–141.

[39] Eom H, Kim J, Kim S, et al. Treatment of saline wastewater containing a high concentration of salt using marine bacteria and aerobic granule sludge. J Environ Eng, 2018, 144(5): 1–8.

[40] Ji L, Liu Y, Zhang YF, et al. Study on the treatment of high salinity oil waste water by reverse osmosis technology. Adv Mater Res, 2012, 418–420: 90–93.

[41] Tokuz RY, Eckenfelder WW Jr. Wesley Eckenfelder Jr. The effect of inorganic salts on the activated sludge process performance. Water Res, 1979, 13: 99–104.

[42] Qu Y, Zhang PY, Yang RX, et al. Characteristics of removal nitrogen and halotolerancy of halotolerant heterotrophic nitrifying strain qy18 and moderately halophilic heterotrophic nitrifying strain gs2. Mar Environ Sci, 2011, 30(3): 337–341 (in Chinese).曲洋, 張培玉, 楊瑞霞, 等. 耐鹽異養(yǎng)硝化菌qy18和中度嗜鹽異養(yǎng)硝化菌gs2的脫氮特性與耐鹽性研究. 海洋環(huán)境科學(xué), 2011, 30(3): 337–341.

[43] Woolard CR, Irvine RL. Biological treatment of hypersaline wastewater by a biofilm of halophilic bacteria. Water Environ Res, 1994, 66(3): 230–235.

[44] Han YH, Zhang WX, Zhuang ZG, et al. Isolation and characterization of the salt-tolerant aerobic denitrifying bacterial strain A-13. Acta Microbiol Sin, 2013, 53(1): 47–58 (in Chinese).韓永和, 章文賢, 莊志剛, 等. 耐鹽好氧反硝化菌A-13菌株的分離鑒定及其反硝化特性. 微生物學(xué)報(bào), 2013, 53(1): 47–58.

[45] Zhang QL, Liu Y, Ai GM, et al. The characteristics of a novel heterotrophic nitrification-aerobic denitrification bacterium,strain L7. Bioresour Technol, 2012, 108: 35–44.

[46] Guo Y, Zhou XM, Li YG, et al. Heterotrophic nitrification and aerobic denitrification by a novel. Biotechnol Lett, 2013, 35(12): 2045–2049.

[47] Tsuneda S, Mikami M, Kimochi Y, et al. Effect of salinity on nitrous oxide emission in the biological nitrogen removal process for industrial wastewater. J Hazard Mater, 2005, 119(1/3): 93–98.

[48] Zheng HY, Liu Y, Gao XY, et al. Characterization of a marine origin aerobic nitrifying-denitrifying bacterium. J Biosci Bioeng, 2012, 114(1): 33–37.

[49] Yao RL, Qiu LN, Zhang WW, et al. Isolation and characteristics of heterotrophic nitrification-aerobic denitrification bacterium,X7 at high salinity. Adv Mater Res, 2014, 864–867: 111–114.

[50] Wang T, Li J, Zhang LH, et al. Simultaneous heterotrophic nitrification and aerobic denitrification at high concentrations of NaCl and ammonia nitrogen bybacteria. Water Sci Technol, 2017, 76(2): 386–395.

[51] Halm? G, Eimhjellen K. Low temperature removal of nitrate by bacterial denitrification. Water Res, 1981, 15(8): 989–998.

[52] Wei W, Huang TL. Isolation and identification of a low temperature and aerobic denitrifier and its denitrification characteristics. Water Technol, 2012, 6(6): 12–16 (in Chinese).魏巍, 黃廷林. 低溫好氧反硝化菌的分離鑒定及脫氮特性研究. 供水技術(shù), 2012, 6(6): 12–16.

[53] Ye Q, Li KL, Li ZL, et al. Heterotrophic nitrification-aerobic denitrification performance of strain Y-12 under low temperature and high concentration of inorganic nitrogen conditions. Water, 2017, 9(11): 835–845.

[54] Qu D, Wang C, Wang YF, et al. Heterotrophic nitrification and aerobic denitrification by a novel groundwater origin cold-adapted bacterium at low temperatures. RSC Adv, 2014, 5(7): 5149–5157.

[55] Zhang DY, Li WG, Huang XF, et al. Removal of ammonium in surface water at low temperature by a newly isolatedsp.strainSFA13. Bioresour Technol, 2013, 137: 147–152.

[56] Dziewit L, Bartosik D. Plasmids of psychrophilic and psychrotolerant bacteria and their role in adaptation to cold environments. Front Microbiol, 2014, 5: 596.

[57] Feng Y. Research on the response mechanism of heterotrophic nitrification-aerobic denitrification bacterial HN-02 antioxidant enzyme system under low-temperature shock[D]. Chengdu: Southwest Jiaotong University, 2014 (in Chinese).馮葉. 低溫沖擊對(duì)異養(yǎng)硝化-好氧反硝化菌HN-02的影響研究[D]. 成都: 西南交通大學(xué), 2014.

[58] Ye BJ. Study of the microbial metabolic activities by the Microcalorimetric method[D]. Lanzhou: Lanzhou University, 2008 (in Chinese).葉丙靜. 微生物代謝活性的微量熱研究[D]. 蘭州: 蘭州大學(xué), 2008.

[59] Liu B. Research and application on thermal and mass transfer in the integrated using of biologic substance[D]. Chongqing: Chongqing University, 2008 (in Chinese). 劉彬. 有機(jī)物綜合利用中的傳熱傳質(zhì)分析與應(yīng)用[D]. 重慶: 重慶大學(xué), 2008.

[60] Liu J. Biological character research of the activated sludge/biofilm process treating Municiple wastewater in North area[D]. Harbin: Harbin Institute of Technology, 2006 (in Chinese).劉杰. 活性污泥/生物膜工藝處理北方城市污水微生物特性研究[D]. 哈爾濱: 哈爾濱工業(yè)大學(xué), 2006.

[61] Jiang W, Li J, Meng LQ, et al. Effect of environmental factors on ammonium removal ofwsw-1001 at low temperature. Environ Sci Technol, 2014, 37(1): 27–30 (in Chinese).姜威, 李晶, 孟利強(qiáng), 等. 環(huán)境因素對(duì)熒光假單胞桿菌低溫脫氮的影響. 環(huán)境科學(xué)與技術(shù), 2014, 37(1): 27–30.

[62] He TX, Ni JP, Li ZL, et al. Heterotrophic nitrification and aerobic denitrification of the hypothermia aerobic denitrification bacterium:. Environ Sci, 2016, 37(3): 1082–1088 (in Chinese). 何騰霞, 倪九派, 李振輪, 等. 1株菌的耐冷異養(yǎng)硝化和好氧反硝化作用. 環(huán)境科學(xué), 2016, 37(3): 1082–1088.

[63] Yi X, He TX, Li ZL, et al. Nitrogen removal characteristics ofY-9 capable of heterotrophic nitrification and aerobic denitrification at low temperature. Biomed Res Int, 2017, 2017: 1429018.

[64] He Y, Zhao YC, Zhou GM. Research progress on the denitrogenation of highly concentrated ammonium-nitrogen wastewater. Ind Water Treat, 2008, 28(1): 1–4 (in Chinese).何巖, 趙由才, 周恭明. 高濃度氨氮廢水脫氮技術(shù)研究進(jìn)展. 工業(yè)水處理, 2008, 28(1): 1–4.

[65] Liu YM, Hao ZL. Treatment technologies and research status of highly concentrated ammonium-nitrogen wastewater. Technol Water Treat, 2012, 38(S1): 7–11 (in Chinese).劉亞敏, 郝卓莉. 高氨氮廢水處理技術(shù)及研究現(xiàn)狀. 水處理技術(shù), 2012, 38(S1): 7–11.

[66] Vadivelu VM, Keller J, Yuan Z. Effect of free ammonia and free nitrous acid concentration on the anabolic and catabolic processes of an enriched nitrosomonas culture. Biotechnol Bioeng, 2010, 95(5): 830–839.

[67] Ciudad G, Rubilar O, Mu?oz P, et al. Partial nitrification of high ammonia concentration wastewater as a part of a shortcut biological nitrogen removal process. Process Biochem, 2005, 40(5): 1715–1719.

[68] Wang JF, Tu BH, Chen RP, et al, Application and development of new biological nutrient removal technology. Techniq Equip Environ Pollut Control, 2003, 4(9): 70–73 (in Chinese).王建芳, 涂寶華, 陳榮平, 等. 生物脫氮除磷新工藝的研究進(jìn)展. 環(huán)境污染治理技術(shù)與設(shè)備, 2003, 4(9): 70–73.

[69] Liao XH. Study on the optimizing ability and gas production of heterotrophic nitrification-aerobic denitrification strains[D]. Beijing: Beijing Technology and Business University, 2009 (in Chinese).廖小紅. 異養(yǎng)硝化-好氧反硝化菌優(yōu)選及脫氮產(chǎn)物研究[D]. 北京: 北京工商大學(xué), 2009.

[70] Shoda M, Ishikawa Y. Heterotrophic nitrification and aerobic denitrification of high-strength ammonium in anaerobically digested sludge bystrain No. 4. J Biosci Bioeng, 2014, 117(6): 737–741.

[71] Yang XH. Isolation and characteristics study of a heterotrophic nitrification-aerobic denitrification fungus[D]. Shanxi: Taiyuan University of Technology, 2012 (in Chinese). 楊曉華. 一株異養(yǎng)硝化好氧反硝化真菌的篩選及特性研究[D]. 山西: 太原理工大學(xué), 2012.

[72] Song YJ, Li Y, Liu YX, et al. Effect of carbon and nitrogen sources on nitrogen removal by a heterotrophic nitrification-aerobic denitrification strain Y1. Acta Sci Circumst, 2013, 33(9): 2491–2497 (in Chinese). 宋宇杰, 李屹, 劉玉香, 等. 碳源和氮源對(duì)異養(yǎng)硝化好氧反硝化菌株Y1脫氮性能的影響. 環(huán)境科學(xué)學(xué)報(bào), 2013, 33(9): 2491–2497.

[73] Xin X, Yao L, Lu L, et al. Identification of a high ammonia nitrogen tolerant and heterotrophic nitrification-aerobic denitrification bacterial strain TN-14 and its nitrogen removal capabilities. Environ Sci, 2014, 35(10): 3926–3932 (in Chinese).信欣, 姚力, 魯磊, 等. 耐高氨氮異養(yǎng)硝化-好氧反硝化菌TN-14的鑒定及其脫氮性能. 環(huán)境科學(xué), 2014, 35(10): 3926–3932.

[74] Wang TY, Wei HF, Hu ZQ, et al. Isolation and identification of a heterotrophic nitrifying and aerobic denitrifying strain and its denitrification characteristics. Acta Sci Circumst, 2017, 37(3): 945–953 (in Chinese). 王田野, 魏荷芬, 胡子全, 等. 一株異養(yǎng)硝化好氧反硝化菌的篩選鑒定及其脫氮特性. 環(huán)境科學(xué)學(xué)報(bào), 2017, 37(3): 945–953.

[75] Yu DY, Zhang LY, Gao B. Factors affecting the heterotrophic nitrification property of heterotrophic nitrification-aerobic denitrifier. Chem Ind Eng Prog, 2012, 31(12): 2797–2800 (in Chinese).于大禹, 張琳穎, 高波. 異養(yǎng)硝化-好氧反硝化菌異養(yǎng)硝化性能的影響因素. 化工進(jìn)展, 2012, 31(12): 2797–2800.

[76] Liao XH, Wang P, Diao HF, et al. Heterotrophic nitrification-aerobic denitrification ability ofWXZ-8. Environ Poll Control, 2009, 31(7): 17–20 (in Chinese). 廖小紅, 汪蘋(píng), 刁惠芳, 等. 蠟狀芽孢桿菌WXZ-8的異養(yǎng)硝化/好氧反硝化性能研究. 環(huán)境污染與防治, 2009, 31(7): 17–20.

[77] Xiao JB, Jiang HX, Chu SY. Isolation and identification of aerobic denitrifying bacteriumstrainDN7 and its heterotrophic nitrification ability. Chin J Appl Ecol, 2012, 23(7): 1979–1984 (in Chinese). 肖繼波, 江惠霞, 褚淑祎. 好氧反硝化菌str.DN7的分離鑒定和異養(yǎng)硝化性能. 應(yīng)用生態(tài)學(xué)報(bào), 2012, 23(7): 1979–1984.

[78] Su JF, Zhang K, Huang TL, et al. Heterotrophic nitrification and aerobic denitrification at low nutrient conditions by a newly isolated bacterium,sp.SYF26. Microbiology, 2015, 161(4): 829–837.

[79] Huang TL, Zhou SL, Zhang HH, et al. Nitrogen removal characteristics of a newly isolated indigenous aerobic denitrifier from oligotrophic drinking water reservoir,sp.N299. Int J Mol Sci, 2015, 16(5): 10038–10060.

[80] Li JD. Study on carbon source supplement for denitrification[D]. Shanghai: Tongji University, 2007 (in Chinese). 李基東. 反硝化脫氮補(bǔ)充碳源選擇與研究[D]. 上海: 同濟(jì)大學(xué), 2007.

[81] Wang HY, Song Q, Wang J, et al. Simultaneous nitrification, denitrification and phosphorus removal in an aerobic granular sludge sequencing batch reactor with high dissolved oxygen: Effects of carbon to nitrogen ratios. Sci Total Environ, 2018, 642: 1145–1152.

[82] Giller KE, Witter E, Mcgrath SP. Heavy metals and soil microbes. Soil Biol Biochem, 2009, 41(10): 2031–2037.

[83] Wang Y, Liu YX, An H, et al. Influence of metal ions on nitrogen removal and NO2--N accumulation byC16. Mocrobiology, 2014, 41(11): 2254–2263 (in Chinese).王瑤, 劉玉香, 安華, 等. 金屬離子對(duì)糞產(chǎn)堿桿菌C16的脫氮和亞硝酸鹽積累的影響. 微生物學(xué)通報(bào), 2014, 41(11): 2254–2263.

[84] He D, Zheng MS, Ma T, et al. Interaction of Cr(VI) reduction and denitrification by strainPCN-2 under aerobic conditions. Bioresour Technol, 2015, 185: 346–352.

[85] Kim JK, Park KJ, Cho KS, et al. Aerobic nitrification-denitrification by heterotrophicstrains. Bioresour Technol, 2005, 96(17): 1897–906.

[86] Pan YJ, Liu F, Meng S, et al. Isolation and characterization of an aerobic denitrifying-heterotrophic bacterium. Chin J Environ Eng, 2016, 34(1): 41–46 (in Chinese). 潘玉瑾, 劉芳, 孟爽, 等. 好氧反硝化菌.ZPQ2的篩選及其反硝化條件優(yōu)化. 環(huán)境工程, 2016, 34(1): 41–46.

[87] Yang YL, Huang SB, Zhang YQ, et al. Nitrogen removal byTAD1 and its denitrification gene identification. Appl Biochem Biotechnol, 2014, 172(2): 829–839.

[88] Joo HS, Hirai M, Shoda M. Piggery wastewater treatment usingstrain No.4 with heterotrophic nitrification and aerobic denitrification. Water Res, 2006, 40(16): 3029–3036.

Advances in heterotrophic nitrification-aerobic denitrifying bacteria for nitrogen removal under extreme conditions

Jianhua Yuan1, Tiantao Zhao1,2, and Xuya Peng1

1 College of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400045, China 2 College of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China

Heterotrophic nitrification-aerobic denitrification (HN-AD) is an enrichment and breakthrough theory of traditional autotrophic nitrification heterotrophic denitrification. Heterotrophic nitrification-aerobic denitrifiers with the feature of wide distribution, strong adaptability and unique metabolic mechanism have many special advantages, including fast-growing, rapid biodegradability and long lasting activity, which can rapidly remove ammonia nitrogen, nitrate nitrogen (NO3–-N) and nitrite nitrogen (NO2–-N) under aerobic conditions simultaneously. Therefore, HN-AD bacteria show the important potential for denitrification under extreme conditions with high-salt, low-temperature or high-ammonia nitrogen environment, and HN-AD bacteria attract extensive attention in the field of biological denitrification of wastewater. In this review, we first introduce the previously reported HN-AD bacterial species which have denitrification performance in the extreme environments and state their typical metabolic mechanism. Then, we systematically analyze the nitrogen removal characteristics and potential under extreme conditions. We also briefly describe the progress in the application of HN-AD bacterial. Finally, we outlook the application prospects and research directions of HN-AD denitrification technology.

heterotrophic nitrification-aerobic denitrification, metabolic mechanism, extreme conditions, biological nitrogen removal

October 17, 2018;

March 5, 2019

National Natural Science Foundation of China (No. 51708077), Social and Livelihood Projects of Chongqing (No. cstc2018jscx-mszd0188).

Tiantao Zhao. Tel/Fax: +86-23-62563225; E-mail: zhaott@cqut.edu.cn

國(guó)家自然科學(xué)基金 (No. 51708077)，重慶市社會(huì)民生項(xiàng)目 (No. cstc2018jscx-mszd0188) 資助。

10.13345/j.cjb.180427

袁建華, 趙天濤, 彭緒亞. 極端條件下異養(yǎng)硝化-好氧反硝化菌脫氮的研究進(jìn)展. 生物工程學(xué)報(bào), 2019, 35(6): 942–955.

Yuan JH, Zhao TT, Peng XY. Advances in heterotrophic nitrification-aerobic denitrifying bacteria for nitrogen removal under extreme conditions. Chin J Biotech, 2019, 35(6): 942–955.

(本文責(zé)編 陳宏宇)