PVC塑料浸出液对3种海洋微藻光合作用及生长的影响

海洋微塑料作为一类新型环境污染物已经成为全球性环境问题。运用水样叶绿素荧光仪(Water-PAM)研究了不同浓度软聚氯乙烯(polyvinyl chloride, PVC)和硬PVC浸出液(0、50、100和200 g·L~(-1))胁迫下球等鞭金藻(Isochrysis galbana)、中肋骨条藻(Skeletonema costatum)和小球藻(Chlorella sp.)3种海洋微藻叶绿素荧光特性,包括PSⅡ最大量子产量(F_v/F_m)、PSⅡ实际量子产量(Yield)、光化学淬灭(qP)和PSⅡ最大相对电子传递速率(rETR_(max))的变化,同时检测微藻的生长状况。结果表明,球等鞭金藻(金藻门)和中肋骨条藻(硅藻门)的4项光合作用参数在软PVC浸出液胁迫的96 h内均显著下降,且随软PVC浸出液浓度增加,下降幅度增大,在实验后期(48～96 h)达到最小值,表现为抑制作用。96 h时,球等鞭金藻和中肋骨条藻的细胞密度均在软PVC浸出液200 g·L~(-1)处理组达到最小值,分别占对照组的3.20%和11.90%。硬PVC浸出液胁迫对球等鞭金藻和中肋骨条藻的4项光合作用参数具有显著影响(P<0.05),球等鞭金藻的4项参数均显著高于对照组。中肋骨条藻的相关光合作用参数均显著低于对照组。72 h时球等鞭金藻和中肋骨条藻的细胞密度分别在硬PVC浸出液100 g·L-1和200 g·L~(-1)处理组达到最小值,为对照组的67.90%和82.50%,表现为抑制作用。小球藻(绿藻门)的各光合作用参数和细胞密度在软PVC和硬PVC浸出液胁迫的96 h内未产生显著变化。该研究证实PVC浸出液对微藻光合系统具有干扰作用,对海洋生态系统具有潜在风险。     

温度对制革污泥的生物淋滤除铬效果的影响

温度对利用嗜酸性硫杆菌脱除污泥中重金属的生物淋滤技术有着重要影响.本试验采用序批式摇床培养,在12～36℃范围内,研究温度对生物淋滤法脱除制革污泥中重金属铬效果的影响.结果表明,随着温度升高,污泥pH值下降以及ORP和SO42-上升的速率均显著提高,污泥中Cr的溶出率相应加快.反应温度在28～36℃时,制革污泥中接种嗜酸性硫杆菌同时添加4 g/L的S粉作为能源物质,生物淋滤反应8d,Cr的溶出率可高达100%.控温在28℃较适宜今后的工程应用.     

Isolation and characterization of a heavy metal-resistant Burkholderia sp. from heavy metal-contaminated paddy field soil and its potential in promoting plant growth and heavy metal accumulation in metal-polluted soil

A heavy metal-resistant bacterial strain was isolated from heavy metal-contaminated soils and identified as Burkholderia sp. J62 based on the 16S rDNA gene sequence analysis. The heavy metal- and antibiotic resistance, heavy metal solubilization of the isolate were investigated. The isolate was also evaluated for promoting plant growth and Pb and Cd uptakes of the plants from heavy metal-contaminated soils in pot experiments. The isolate was found to exhibit different multiple heavy metal and antibiotic resistance characteristics. Atomic absorption spectrometer analysis showed increased bacterial solubilization of lead and cadmium in solution culture and in soils. The isolate produced indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. The isolate also solubilized inorganic phosphate. Inoculation with the isolate was found to significantly (p < 0.05) increase the biomass of maize and tomato plants. Increase in tissue Pb and Cd contents varied from 38% to 192% and from 5% to 191% in inoculated plants growing in heavy metal-contaminated soils compared to the uninoculated control, respectively. These results show that heavy metal-solubilizing and plant growth promoting bacteria are important for plant growth and heavy metal uptake which may provide a new microbial enhanced-phytoremediation of metal-polluted soils.     

Atrazine biodegradation modulated by clays and clay/humic acid complexes

The fate of pesticides in the environment is strongly related to the soil sorption processes that control not only their transfer but also their bioavailability. Cationic (Ca-bentonite) and anionic (Layered Double Hydroxide) clays behave towards the ionisable pesticide atrazine (AT) sorption with opposite tendencies: a noticeable sorption capacity for the first whereas the highly hydrophilic LDH showed no interactions with AT. These clays were modified with different humic acid (HA) contents. HA sorbed on the clay surface and increased AT interactions. The sorption effect on AT biodegradation and on its metabolite formation was studied with Pseudomonas sp. ADP. The biodegradation rate was greatly modulated by the material's sorption capacity and was clearly limited by the desorption rate. More surprisingly, it increased dramatically with LDH. Adsorption of bacterial cells on clay particles facilitates the degradation of non-sorbed chemical, and should be considered for predicting pesticide fate in the environment.     

异养硝化-好氧反硝化菌ADN-42的脱氮特性

从大连海域典型繁茂膜海绵(Hymeniacidon perleve)中筛选出1株耐盐异养硝化-好氧反硝化菌,通过形态观察、生理生化实验和16S rRNA基因序列分析,确定其为假单胞菌属(Pseudomonas),命名为ADN-42。其异养硝化-好氧反硝化条件为氯化铵为氮源,柠檬酸三钠为碳源,温度30℃,C/N值为12,摇床转速150 r/min,NH+4-N初始浓度约300 mg/L,盐度为40 g/L Na Cl,在此条件下菌株84 h时NH+4-N去除率为75.4%,无硝态氮产生,亚硝态氮最大积累量为8.3 mg/L;将菌株投加到NH+4-N和NO-2-N混合体系中,混合系统比仅以NH+4-N为氮源的体系的NH+4-N去除速率提高了12.7%;研究结果表明Pseudomonas sp.ADN-42可能是一株有着良好应用前景的高效耐盐异养硝化-好氧反硝化菌。     

固定化毛霉对工业和农田污染土壤中多环芳烃的降解和生物有效性评价

为了探讨微生物修复不同类型多环芳烃污染土壤的可行性,应用固定化毛霉对多环芳烃污染工业土壤及农田土壤进行微生物修复,用羟丙基-β-环糊精(HPCD)提取模拟评价多环芳烃的微生物可利用性,并分析多环芳烃微生物降解和生物可利用性的相关关系.焦化厂污染土壤中多环芳烃的30 d降解率为77.6%,沈抚灌区污染土壤中多环芳烃的30 d降解率为54.2%,焦化厂土壤和污灌区农田土壤中多环芳烃降解差异明显.焦化厂土壤和污灌区土壤中多环芳烃的30 d降解量和多环芳烃的环糊精可提取量具有相关性,各环数多环芳烃的环糊精可提取量变化解释了焦化厂和污灌区土壤中多环芳烃降解的差异机制,说明可用环糊精提取量预测微生物降解土壤多环芳烃的情况.     

15种取代酚对淡水发光菌Q67的毒性及定量构效分析

为了更加准确和便捷地预测各种取代酚类化合物的急性毒性,以淡水发光菌Q67(Vibrio qinghaiensis sp.-Q67)为受试生物,测定了15种典型取代酚的急性毒性;采用logD(正辛醇/水分配系数),LUMO(分子最低空轨道能)和MW(分子量)等取代酚的7种主要结构参数,利用偏最小二乘回归法建立了定量结构-活性相关(quantitative structure-activity relationships,QSAR)模型。结果表明,15种取代酚的EC_(50)在5.76×10~(-6)～1.27×10~(-3)mol·L~(-1)之间,且有很好的剂量-效应关系;QSAR模型的主成分分析显示,-logEC_(50)与logD、LUMO和MW值正相关,且logD对模型的贡献最大,即越容易与Q67菌结合的酚类化合物对其的急性毒性越大;建立的QSAR模型具有较好的预测能力(Q~2_(EXT)=0.91,RMSE=0.49)和较高的稳定性(Q~2_(CUM)=0.58),能够用于预测其他酚类化合物对Q67菌的急性毒性。     

氯代酰胺类除草剂降解菌的分离及降解性能

从生产乙草胺的农药厂废水生物处理池活性污泥中分离到一株氯代酰胺类除草剂降解细菌,命名为Y3B-1.根据表型特征、生理生化特性和16S rDNA序列系统发育分析,将其鉴定为副球菌属(Paracoccus sp.).研究了菌株Y3B-1在不同条件下对多种氯代酰胺类除草剂的降解性能.结果表明:菌株Y3B-1能以乙草胺为碳源生长,并能降解乙草胺、丁草胺和丙草胺,3 d对这3种氯代酰胺类除草剂的降解率分别达到86.7%、65.5%和69.1%,不能降解异丙甲草胺.该菌降解乙草胺的最适温度为30℃,最适pH为7.0,对乙草胺的降解效果与接种量成正相关,对较低浓度的乙草胺有很好的降解效果,过高的起始浓度抑制其对乙草胺的降解,外加营养如酵母膏和土壤悬液则显著促进其对乙草胺的降解.图7参23     

黄杆菌(Flavobacterium sp.)对溴氨酸脱色的研究

从受污土壤中筛选出对溴氨酸具有高效脱色能力的黄杆菌BX26．通过监测液体培养基中细胞浊度和溴氨酸吸光度的变化,考察了碳源浓度、溴氨酸浓度和以溴氨酸为唯一碳、氮、硫源时对菌体生长和溴氨酸脱色的影响．结果表明,BX26对溴氨酸的脱色在于酶的催化作用．该脱色酶属诱导性胞外酶．酶的诱导和产生需要液体培养基中有足量的氮源和硫源,但对碳源没有要求．溴氨酸对菌体的生长具有明显的促进作用,同时菌株也表现出很高的溴氨酸脱色活性,可使高达1000mg/L的溴氨酸降解脱色．菌体不能以溴氨酸为唯一碳、氮、硫源,但可以溴氨酸的脱色产物为唯一碳源．     

喹啉降解菌筛选及其对焦化废水强化处理

以喹啉为目标污染物,从焦化厂废水处理工段活性污泥中分离出1株能利用喹啉作为唯一碳源、氮源及能源的高效降解菌DQS-01,经16S rRNA基因分析鉴定为丛毛单胞菌科食酸菌属(Acidovorax sp.)菌株.通过考察不同培养条件下DQS-01降解菌的生物量及喹啉降解率随时间的变化,确定其最佳降解条件为接种量10%、摇瓶转速150 r·min-1、初始p H 8.0~10.0、温度35℃.应用Haldane方程对该菌在不同喹啉初始浓度下的生长动力学过程进行了模拟,拟合曲线与实验测定值相关性良好.将该菌与高效苯酚降解菌混合菌株用于焦化废水的生物强化处理,在移动床生物膜反应器(moving-bed biofilm reactor,MBBR)运行72 h后,对焦化废水COD的降解率达到87.4%.