不同培养条件下锰过氧化物酶(MnP)的合成及其对甲基橙的降解

高效、大规模、低成本合成木质素降解酶是直接采用其降解难降解有机污染物所必须解决的问题.对锰过氧化物酶(MnP)降解甲基橙和在非灭菌的反应器中连续合成MnP的可行性进行考察.结果表明,在采用2 mmol H2O2和1.5 mmol MnSO4的降解体系中,获最大脱色效果,且100、200和300 U/L的MnP可在8h内将甲基橙分别脱色18％、23％和35％;在非灭菌的反应器水平上实现了固定化培养的P.chrysosporium连续23 d合成MnP,但MnP酶活仅为2～ 23 U/L,难以酶解甲基橙;然而,在摇瓶培养条件下固定化的P.chrysosporium合成的MnP却能达1 152 U/L.因此,直接采用MnP对污染物进行降解以及在非灭菌的反应器中持续合成MnP是可行的,但就在非灭菌条件下如何提高MnP的合成量还有待开展深入的研究.     

Biological Activity in a Heavily Organohalogen-Contaminated River Sediment (8 pp)

Background, Aims and Scope Sediments of the Spittelwasser creek are highly polluted with organic compounds and heavy metals due to the discharge of untreated waste waters from the industrial region of Bitterfeld-Wolfen, Germany over the course of more than one century. However, relatively few data have been published about the chloroorganic contamination of the sediment. This paper reports on the content of different (chloro)organic compounds with special emphasis on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F), and chlorobenzenes. Existing concepts for the remediation of Spittelwasser sediment include the investigation of natural attenuation processes, which largely depend on the presence of an intact microbial food web. In order to gain more insight in terms of biological activity, we analyzed the capacity of sediment microflora to degrade organic matter by measuring the activities of extracellular hydrolytic enzymes involved in the biogeochemical cycling of carbon, nitrogen, phosphorus and sulfur. Furthermore, the detection of physiologically active bacteria in the sediment, particularly of those known for their capability to reductively dehalogenate organochlorine compounds, illustrates the potential for intrinsic bioremediation processes. Methods PCDD/F and chlorobenzenes were analyzed by gas chromatography(GC)/mass spectrometry and GC/flame ionization detection, respectively. The activities of hydrolytic enzymes were determined from freshly sampled sediment layers using 4-methylumbelliferyl (MUF) or 7-amino-4-methylcoumarin-conjugated model compounds and kinetic fluorescence measurements. Physiologically active bacteria from different sediment layers were microscopically visualized by fluorescence in situ hybridization (FISH). Specific bacteria were identified by 16S rRNA gene amplification and sequencing. Results and Discussion The PCDD/F congener profile was dominated by dibenzofurans. In addition, the presence of specific tetra and pentachlorinated dibenzofurans supported the assumption that extensive magnesium production was one possible source for the high contamination. A range of other chloroorganic compounds, including several isomers of chlorobenzenes, hexachlorocyclohexane and 1,1,1-trichloro-2,2-bis (p-chloro-phenyl)ethane (DDT), was present in the sediment. Activities of extracellular hydrolytic enzymes showed a strong decrease in those sediment layers that were characterized by high contents of absorbable organic halogen (AOX), indicating disturbed organic matter decay. Interestingly, an abnormal increase of cellulolytic enzyme activities below the organochlorine-rich layers was observed, possibly caused by residual cellulose from discharges of sulfite pulping wastes. FISH revealed physiologically active bacteria in most sediment layers from the surface down to the depth of about 60 cm, including members of Desulfitobacterium (D.) and Sulfurospirillum. The presence of D. dehalogenans was confirmed by its partial 16S rRNA gene sequence. Conclusions Results of chemical sediment analyses demonstrated high loads of organochlorine compounds, particularly of PCDD/F. Several years after stopping the waste water discharge to Spittelwasser creek, this sediment remains a main source for pollution of the downstream river system by way of the ongoing mobilization of sediment during high floods. As indicated by our enzyme activity measurements, the decomposition potential for organic matter is low in organochlorine-rich sediment layers. In contrast, the comparably higher enzyme activities in less organochlorine-polluted sediment layers as well as the presence of physiologically active bacteria suggest a considerable potential for natural attenuation. Recommendations and Perspectives From our data we strongly recommend to explore the degradative capacity of sediment microorganisms and the limits for in situ activity towards specific sediment pollutants in more detail. This will give a sound basis for the integration of bioremediation approaches into general concepts to reduce the risk that permanently radiates from this highly contaminated sediment. Submission Editor: Dr. Henner Hollert (Henner.Hollert@urz.uniheidelberg.de)     

固定化微藻流化床反应器去除低碳污水中氨氮的潜力

以固定化微藻颗粒为原料,通过搭建流化床反应器强化微藻对氨氮（NH₄⁺-N）的去除,设计了藻种、污水上升流速、光周期和光照强度四组单一变量实验,系统地研究了不同条件下微藻去除NH₄⁺-N的能力.结果表明,当以固定化斜生栅藻为原料、污水上升流速为6.8m/h、光周期为8：16h和光照强度为4800Lux时,NH₄⁺-N去除效果最优（96.7%）.在最优操作条件下,探究了COD为200mg/L时微藻去除NH₄⁺-N的潜力,结果表明,当NH₄⁺-N初始浓度不高于50mg/L时,NH₄⁺-N去除率高于95%.本实验建立了一套半连续微藻流化床实验方法,该方法显著减弱了微藻在生物同化过程中对有机碳源的依赖性,为低COD条件下微藻生物脱氮工艺的设计提供了技术参考和理论基础.     

不同基质生物炭对厌氧处理餐厨垃圾效能及微生态的影响

探究了剩余污泥（SS）、餐厨垃圾（FW）、玉米芯（CC）、甘蔗渣（BG）4种不同基质生物炭对厌氧生物处理餐厨垃圾效能的影响,对厌氧污泥的关键酶活性、微生物群落分布以及代谢途径等微生态进行了分析.结果表明,厌氧反应器分别加入4种生物炭后,COD平均去除率分别提高了29.49%、23.16%、29.42%、40.32%;傅里叶红外分析表明,投加SS生物炭组出水中羟基、酰胺基以及C-O-C伸缩振动峰减弱.4个厌氧反应器中厌氧污泥的乙酸激酶活性分别为0.40,0.42,0.96,0.98 μmol/g,表明投加CC与BG生物炭促进了餐厨垃圾的厌氧水解酸化过程;厌氧污泥胞外聚合物的蛋白质/多糖之比分别为0.415、0.56、1.89、2.8,投加CC、BG生物炭提高了污泥的稳定性.4个厌氧反应器中拟杆菌门、变形菌门、厚壁菌门为主要菌群,投加BG生物炭促进了变形菌门与厚壁菌门的生长;对于古细菌而言,甲烷杆菌属与甲烷丝菌属为优势种群,SS组的甲烷杆菌属丰度最高（53.48%）,而BG组中甲烷丝菌属丰度最高（42.72%）.KEGG功能分析表明古菌及细菌均以碳水化合物代谢、氨基酸代谢为主;而投加BG与SS生物炭后,微生物膜运输水平得到了提高.     

构树修复对重金属污染土壤环境质量的影响

通过温室盆栽试验,研究构树（Broussonetia papyrifera）生长对重金属污染土壤酶活性和微生物群落结构的影响.结果表明,构树修复污染土壤中酶活性和微生物多样性明显提高.经270d培养后,构树生长土壤中蔗糖酶和酸性磷酸酶活性与种植土壤相比分别显著（P<0.05）提高3.12倍和2.29倍;土壤脱氢酶与有效态As、Cd、Pb、Zn和Cu含量,蔗糖酶与有效态Cd含量,以及磷酸酶与有效态Cd和Cu含量之间呈显著负相关（P<0.05）.根据16S和18S rDNA PCR-DGGE分析表明,构树修复可提高污染土壤中细菌和丛枝菌根真菌多样性.上述结果表明,构树修复可有效改善重金属污染土壤的环境质量.然而,污染土壤中重金属有效态含量下降不明显,必须辅助物理和化学措施来强化构树对重金属污染土壤的生态修复潜力.     

Time dependent influx and efflux of phenol by immobilized microbial consortium

Phenol, like many other organic solvents, is toxic to micro-organisms even at low concentrations. However, some micro-organisms can withstand this toxicity to a certain concentration. To observe the uptake mechanism of phenol, bacteria were isolatedfrom a petroleum refinery effluent and identified. Study was carried out to understand the effect of varying sub-lethal concentrations of phenol, on all the isolated individual bacterial cultures. Out of the bacteria isolated, Serratia liquefaciens was found to tolerate phenol concentration up to 1500 mg l^-1. A microbial consortium of the isolated bacteriawas formulated and immobilized. Individual cultures were also immobilized and uptake of phenol by the immobilized micro-organisms was observed in a nutrient-rich and nutrient-stressed medium containing phenol as a sole source of carbon. A time-dependent uptake of phenol was exhibited by the micro-organismsin nutrient-stressed medium, after which a sudden increase in phenol concentration occurred in the extracellular medium, till it reached back to the initial concentration. This was attributedto an active efflux mechanism adopted by the micro-organisms to withstand the toxic shock.     

有机磷酸酯诱导迟发性神经毒性及其对神经毒性酯酶（NTE）活性影响的动态研究

以成年产卵来航母鸡为试验动物，研究了三甲基苯基磷酸酯（Ｔｒｉ－ｏ－ＣｒｅｓｙｌＰｈｏｓ－ｐｈａｔｅ，ＴＯＣＰ）诱导的迟发性神经毒性．试验发现，母鸡口服ＴＯＣＰ（７５０ｍｇ／ｋｇ）后，经过大约８－１０ｄ的潜伏期开始出现中毒症状，其表现为以步态失调为主要特征的运动障碍呈进行性加重，至第２１ｄ开始便发展为瘫痪，对鸡脑神经病损靶标酯酶（ＮｅｕｒｏｐａｔｈｙＴａｒｇｅｔＥｎｚｙｍｅ，ＮＴＥ）活性的测定表明，有机械诱导的迟发性神经毒性（Ｏｒｇａｎｏｐｈｏｓｐｈａｔｅ－ＩｎｄｕｃｅｄＤｅｌａｙｅｄＰｏｌｙｎｅｕｒｏｐａｔｈｙ，ＯＰＩＤＰ）与ＮＴＥ活性抑制之间的关系不平行，其毒性症状的轻重与ＮＴＥ活性被抑制的强弱也不呈正相关，很可能，在给药后２４ｈ，体内ＯＰＩＤＰ已被触发，此外，实验观察到给予ＴＯＣＰ后被试鸡的体重明显下降。     

生物质炭对Cd污染土壤团聚体酶活性的影响

为探究生物质炭对Cd污染土壤团聚体酶活性的影响,采用盆栽试验,向模拟Cd污染土壤中添加生物质炭并测定水稻根际土壤团聚体碳循环酶与氧化还原酶活性.结果表明:Cd污染土壤团聚体酶活性对添加量为2.5%的生物质炭响应明显,氧化还原酶活性指数值介于0.522~0.792之间.在2.5mg/kg的外源Cd条件下,2.5%的生物质炭比未添加生物质炭处理显著提高蛋白酶与过氧化氢酶活性至121%与653%.在Cd污染土壤中添加生物质炭,碳循环酶与氧化还原酶及综合酶活性均在0.5~1mm中等粒径土壤团聚体中产生富集效应,其酶活性随土壤团聚体粒径的增大呈先升后降最终趋于稳定的趋势.研究显示,在2.5mg/kg的外源Cd条件下,添加2.5%的生物质炭对水稻根际土壤团聚体酶活性影响显著,土壤酶活性受酶种类、生物质炭量与团聚体粒径的综合影响;在Cd污染土壤中添加生物质炭后,土壤酶活性随团聚体粒径的增大呈“∧”形变动规律.     

镍、锌、铝对羊角月芽藻(Selenastrum capricornutum)生长及酶活性影响研究

研究了不同浓度镍，锌，铝对常见绿藻羊角月芽藻生长速度，蛋白质含量，ＡＴＰ水平，葡萄糖－６－磷酸脱氢酶，酸性磷酸酶及硝酸还原酶活性的影响。结果表明３种金属离子在所试浓度范围内对羊角月芽藻的生长速度均有抑制作用，但单位藻培养物中蛋白质含量却随着金属离子浓度的增加而增加；高浓度金属离子对酶活性有明显抑制作用；藻细胞中ＡＴＰ水平随着金属离子浓度的增加而下降。     

水稻烤田期间N2O排放及其影响因素

水稻田间实验研究了烤田期间的土壤温度、Eh、含水量和裂缝基本性质,矿质态氮以及与氮有关的酶活性的演变规律,及其对N2O排放的影响.试验表明,在水稻分蘖期间烤田,N2O有一个排放高峰,其最高值可达75.6μg·m-2·h-1.在排放高峰后,即使继续烤田,N2O的排放值也将降低.N2O排放与尿素氮肥的施用量没有明显关系.裂缝的生成,改变了N2O的日排放规律.随着烤田时间的延长,脲酶和羟胺还原酶活性呈波动变化,硝酸还原酶活性递减,亚硝酸还原酶活性极低.硝酸还原酶活性与N2O排放之间没有显著相关性.土壤中的脲酶活性与N2O日排放通量呈显著的线性正相关.在烤田期间,NO-3含量呈增加趋势.土壤中的硝态氮含量与N2O排放通量之间呈显著正线性关系.土壤中的铵态氮含量与N2O排放通量之间呈显著负线性相关.