无机碳源对栅藻LX1生长及油脂积累特性的影响

以二级出水为培养基,比较了对照组和补充碳源（Na2CO3、NaHCO3和CO2）组栅藻LX1的生长和油脂积累特性.培养14d,4组试验中栅藻LX1的生长及油脂积累特性均无显著差别,藻细胞生物量、油脂及三酰甘油酯产量分别为0.70～0.77、0.27～0.34和0.029～0.033 g.L-1,单位藻细胞油脂含量约为3...     

Microcystin-LR biodegradation by Sphingopyxis sp. USTB-05

A promising bacterial strain for biodegrading microcystin-LR (MC-LR) as the sole carbon and nitrogen source was successfully isolated from Lake Dianchi, China. The strain was identified as Sphingopyxis sp. USTB-05, which was the first isolated MCs-biodegrading Sphingopyxis sp. in China. The average biodegradation rate of MC-LR by Sphingopyxis sp. USTB-05 was 28.8 mg·L⁻¹ per day, which was apparently higher than those of other bacteria reported so far. The optimal temperature and pH for both strain USTB-05 growth and MC-LR biodegradation were 30°C and 7.0, respectively. The release of MC-LR from the cyanobacterial cells collected from Lake Guishui and the biodegradation of MC-LR by both strain and cell-free extract (CE) were investigated. The results indicated that MC-LR with the initial concentration of 4.0 mg·L⁻¹ in water was biodegraded by Sphingopyxis sp. USTB-05 within 4 d, while MC-LR with the initial concentration of 28.8 mg·L⁻¹ could be completely removed in 3 h by CE of Sphingopyxis sp. USTB-05 containing 350 mg·L⁻¹ protein. During enzymatic biodegradation of MC-LR, two intermediate metabolites and a dead-end product were observed on an HPLC chromatogram. Moreover, the similar scanning profiles of MC-LR and its metabolic products indicate that the Adda side-chain of MC-LR was kept intact in all products.     

土壤质地对自养固碳微生物及其同化碳的影响

自养微生物可同化大气中的CO2并将其转化为土壤有机碳,对提高农田土壤的碳吸收和碳储存有重要意义,然而土壤质地对自养固碳微生物功能种群及其同化碳的影响机制还不清楚.本研究选取亚热带地区同一母质发育而成的两种质地水稻土壤(壤质黏土和砂质黏壤土),通过14C-CO2连续标记技术结合室内模拟培养实验,探讨土壤质地对自养微生物同化碳(14C-SOC)、自养微生物截留碳(14C-MBC)和自养微生物可溶性碳(14C-DOC)的影响.以固碳功能基因(cbb L基因)作为指示基因,结合PCR和克隆测序技术,分析不同质地土壤自养固碳微生物群落结构和多样性的差异.结果表明,壤质黏土14C-SOC、14C-MBC和14C-DOC平均含量分别为133.81、40.16和8.10 mg·kg-1,均显著高于砂质黏壤土14C-SOC(104.95 mg·kg-1)、14C-MBC(33.26 mg·kg-1)和14C-DOC(4.18 mg·kg-1)平均含量(P0.05),说明土壤质地显著影响了土壤自养微生物碳同化量以及自养微生物同化碳在土壤中的转化.稀疏曲线、细菌cbb L基因文库覆盖度以及多样性指数分析结果显示壤质黏土固碳细菌群落多样性高于砂质黏壤土.系统发育分析表明,壤质黏土细菌cbb L基因序列与Rhodoblastus acidophilus、Blastochloris viridis、Thauera humireducens、Mehylibium sp.、Variovorax sp.等具有一定的同源性,而砂质黏壤土cbb L基因序列主要与根瘤菌和放线菌同源.可见,土壤质地对自养固碳微生物群落结构和多样性产生了深刻的影响,壤质黏土中较高的黏粒含量、土壤养分含量和阳离子交换量可能有利于维持更高的自养固碳微生物多样性和活性,从而导致不同质地土壤自养微生物碳同化量及其转化存在显著差异.     

小球藻高效净化猪场废水厌氧发酵沼液研究

为了净化脱除养猪场废水厌氧发酵沼液中的主要污染物,本文利用臭氧氧化对沼液灭菌并且降解其中的大分子有机物(效果优于高压蒸汽灭菌法),然后高效培养小球藻转化为生物质变废为宝.研究了通入不同体积浓度CO_2以及在沼液中补充部分营养盐对微藻生长净化沼液的影响.当CO_2体积浓度从2%逐渐增加到30%时,微藻生物质产量和脱除污染物效率先升后降,并在体积浓度为15%时达到峰值.当沼液中补充添加营养盐10 mg·L~(-1)磷和1 mg·L~(-1)铁时,微藻生物质产量相对未添加条件进一步提高了29.1%,达到了5.81 g·L~(-1),相应的COD、TN、NH_3-N、TP和抗生素替米考星等污染物脱除效率分别提高到88.5%、91.2%、93.6%、98.9%和90.7%.因此,小球藻可高效净化猪场厌氧发酵沼液同时生产高值生物质,具有良好的应用前景.     

Selection of microalgae for high CO2 fixation efficiency and lipid accumulation from ten Chlorella strains using municipal wastewater

As significant differences in cellular physiology, metabolic potential and genetics occur among strains with morphological similarity, the screening of appropriate microalgae species for effective CO₂ fixation and biodiesel production is extremely critical. In this study, ten strains of Chlorella were cultivated in municipal wastewater influent (MWI) and their tolerance for MWI, CO₂ fixation efficiency and lipid productivity were assessed. The results showed that the biomass concentrations of four strains (Chlorella vulgaris, Chlorella 64.01, Chlorella regularis var. minima and Chlorella sp.) were significantly higher than other strains. When the cultivation systems were aerated with 10% CO₂, Chlorella sp. showed the highest CO₂ fixation efficiency (35.51%), while the highest lipid accumulation (58.48%) was observed with C. vulgaris. Scanning electron microscopy images revealed that the cells of both Chlorella sp. and C. vulgaris kept their normal morphologies after 15 day batch culture. These findings indicated that Chlorella sp. and C. vulgaris have fairly good tolerance for MWI, and moreover, Chlorella sp. was appropriate for CO₂ fixation while C. vulgaris represented the highest potential for producing biodiesel.     

Phenanthrene sorption to environmental black carbon in sediments from the Song-Liao watershed (China)

Black carbon (BC) in ten contaminated sediments from the Song-Liao watershed, NE China, was isolated upon treatments using a combustion method at 375°C, and the isolates’ sorption isotherms for phenanthrene (Phen) were determined. All sorption isotherms were nonlinear and fitted well by the Freundlich model. A negative relation was found between Freundlich sorption nonlinearity parameter (n values) and BC/total organic carbon (TOC) content of the original sediments (r ² = 0.687, p<0.01), indicating the dominance of BC in Phen sorption nonlinearity. The BC isolates from this industrialized region had n values of 0.342 to 0.505 and logK _FOC values of 6.02 to 6.42 (μg·kg⁻¹·OC⁻¹)/(μg·L⁻¹) ⁿ for Phen. At a given C _e, the BC had higher K _oc value than the original sediments, revealing a higher sorption capacity for BC. BC was responsible for 50.0% to 87.3% of the total sorption at C _e= 0.05 S _w, clearly indicating the dominance of BC particles in overall sorption of Phen by sediments.     

莠去津降解菌HB-5的最佳产酶培养基及发酵条件

从农药厂废水中分离到一株降解莠去滓的节杆菌(Arthrobacter sp.)HB-5,以从该菌中提取到的降解酶对莠去津的降解率为指标,进行最佳产酶培养基及发酵条件的优化研究,对其产酶量进行了评价.通过正交试验和均匀试验,对细菌HB-5的发酵培养基进行了优化研究.运用SAS软件进行结果分析,所获优化培养基配方为:蔗糖3.0g·L-1,莠去津0.38g·L-1,K2HPO40.5g·L-1,KH2PO41.2 g·L-1,MgSO4·7H2O 1.2g·L-1,NaCl 0.1g·L-1,微量元素溶液3.8mL·L-1.得到菌株培养的最佳优化条件为:菌株发酵液培养时间为48h.接种量为2%,发酵液初始pH值为9,250mL三角瓶中装液量为80mL经优化后,降解酶对莠去津的降解率(91.64%)比原培养基(40.67%)提高了125%.     

Cd2+共存时镰刀菌(Fusarium sp.HJ01)降解对氯苯酚的特性与机制

为了解Cd2+对镰刀菌(Fusarium sp.HJ01)降解对氯苯酚(4-CP)的影响,研究了Cd2共存时,浓度、pH、碳源与氮源对镰刀菌降解4-CP特性的影响,并分析了其降解动力学与机理.结果表明,在降解温度、4-CP浓度等相同时,Cd2+共存对镰刀菌降解4-CP有一定的抑制作用.Cd2浓度小于3.O mg·L-1时,随着4-CP浓度的增大,镰刀菌对4-CP的降解速率变慢.镰刀菌降解4-CP的适宜pH为4.外加碳源蔗糖(3.Og·L-1)与外加NH4Cl(3.0 g·L-1)均使镰刀菌降解4-CP速度有所减缓.在Cd2+浓度0.1 ～3.0 mg·L-1时,镰刀菌降解4-CP符合零级动力学方程.Cd2+共存时只对4-CP的降解速率产生一定的抑制作用,而对其降解途径可能无显著影响.     

碳酸盐与磷酸盐对Biohydrogenbacterium R3sp.nov.产氢发酵效能的影响

采用NH4HCO3、NaHCO3、Na2CO3、K2HPO4、KH2HPO4、NaH2PO4和Na2HPO4作为碳酸盐和磷酸盐缓冲溶液源,研究其对Biohydrogenbacterium R3 sp.nov.产氢发酵效能的影响.研究发现,碳酸盐对Biohydrogenbacterium R3 sp.nov.反应体系中的pH值都具有较好的缓冲作用,而磷酸盐的添加对其产氢效能的促进作用较明显.反应器内添加了Na2HPO4与K2HPO4的Biohydrogenbacterium R3 sp.nov.的氢气产量与氢气含量达到最高值,分别为1978.56 mL、44.1％与2160.9 mL、45.8％,此时反应器内的pH值分别为3.28和3.41,细胞浓度分别为1.03 g·L-1和1.21 g·L-1,添加了Na2HPO4的Biohydrogenbacterium R3 sp.nov.的乙醇和乙酸产量分别为4841.49 mg·L-1和2064.94 mg·L-1;而添加了Na2CO3的氢气产量、氢气含量、细胞浓度与反应器内pH值分别为1064.42 mL、35.96％、1.23 g·L-1与3.81,此时乙醇、乙酸的产量分别为3862.21 mg·L-1和1930.86 mg·L-1.     

Microalgae: a promising tool for carbon sequestration

Increasing trends in global warming already evident, the likelihood of further rise continuing, and their impacts give urgency to addressing carbon sequestration technologies more coherently and effectively. Carbon dioxide (CO₂) is responsible for over half the warming potential of all greenhouse gases (GHG), due to the dependence of world economies on fossil fuels. The processes involving CO₂ capture and storage (CCS) are gaining attention as an alternative for reducing CO₂ concentration in the ambient air. However, these technologies are considered as short-term solutions, as there are still concerns about the environmental sustainability of these processes. A promising technology could be the biological capture of CO₂ using microalgae due to its unmatched advantages over higher plants and ocean fertilization. Microalgae are phototrophic microorganisms with simple nutritional requirements, and comprising the major primary producers on this planet. Specific pathways include autotrophic production via both open pond or closed photobioreactor (PBR) systems. Photosynthetic efficiency of microalgae ranged from 10?C20 % in comparison with 1?C2 % of most terrestrial plants. Some algal species, during their exponential growth, can double their biomass in periods as short as 3.5 hours. Moreover, advantage of being tolerant of high concentration of CO₂ (flue gas), low light intensity requirements, environmentally sustainable, and co-producing added value products put these as the favoured organisms. Advantages of microalgae in comparison with other sequestration methodologies are discussed, which includes the cultivation systems, the key process parameters, wastewater treatment, harvesting and the novel bio-products produced by microalgal biomass.     

稻田土壤固碳功能微生物群落结构和数量特征

研究不同类型稻田土壤自养微生物数量和多样性差异及其影响因子,对全面认识稻田生态系统的固碳潜力及其机制具有重要意义.鉴于此,本文选取4种典型稻田土壤,通过室内培养实验对具备卡尔文循环途径碳同化微生物进行了研究.利用荧光定量PCR(qPCR)、克隆文库以及末端限制性长度多态性分析(T-RFLP)技术,研究了卡尔文循环关键酶(1,5二磷酸核酮糖羧化酶/加氧酶Rubis CO)的2种编码基因(cbbL和cbbM)的丰度和多样性.结果表明,与培养前相比,培养45 d后碳同化自养微生物数量有所增加,cbbL基因丰度比cbbM基因高3个数量级.不同稻田土壤中碳同化功能微生物优势种群存在差异,且这些微生物大多不能归类到已知的细菌类群中,部分可归类的与变形菌和放线菌有较高相似度.RDA分析结果显示土壤有机碳(SOC)、阳离子交换量(CEC)、pH、黏粒、粉粒和砂粒含量对碳同化功能微生物群落结构有显著影响.本文的研究结果对于理解微生物在碳循环过程中的作用具有一定的科学意义,也可以为稻田土壤肥力科学化管理和构建低碳农业提供科学依据.     

一种高效微生物絮凝剂产生菌的筛选及培养基优化

从某自来水处理厂的活性污泥中筛选得到了一株稳定高效的微生物絮凝剂产生菌MBF-33,所产絮凝剂对高岭土悬浮液体系有较好的絮凝作用.通过培养基优化,对高岭土的絮凝率从81.3%提高到95%.实验结果表明:(1)适宜的单一碳源为25 g·L-1葡萄糖;(2)复合碳源效果优于单一碳源,适宜的复合碳源为蔗糖5 g·L-1,葡萄糖20 g·L-1;(3)无机氮不利于该菌生长,适宜的氮源为单一有机氮,为1.5 g·L-1蛋白胨;(4)0.2 g·L-1的MgSO4有利于菌生长,但不利于絮凝剂产生.     

1株分离自煤矿废水的铁硫氧化细菌LY01的鉴定及其氧化特性研究

从贵州省某煤矿废水中分离出1株嗜酸性的铁硫氧化细菌菌株LY01,经过对该菌株的形态特征、理化特征检测及16S rRNA序列分析,初步鉴定菌株LY01为嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans).在无机盐培养液中菌株LY01可以从氧化Fe2+、单质硫(S0)及黄铁矿(FeS2)获得能量生长,对Fe2+的氧化速率最快,反应30 h即可将44.2 g.L-1的FeSO4.7H2O完全氧化,菌体细胞达到4.2×107个.mL-1;反应21 d可将溶液中10 g.L-1含量的S0氧化6.7%,溶液中SO24-浓度达2 001 mg.L-1,菌体细胞达到8.9×107个.mL-1;反应20 d可将溶液中30 g.L-1含量的FeS2氧化10%,溶液中SO24-浓度达4 443 mg.L-1,菌体细胞达到3.4×108个.mL-1.研究重金属离子Ni2+、Pb2+对菌株LY01氧化FeS2活性的影响,结果发现10～100 mg.L-1的Ni2+对菌株LY01氧化FeS2活性有一定的影响,而10～100 mg.L-1Pb2+对菌株LY01氧化FeS2的活性无影响.     

Copper and zinc interaction on water clearance and tissue metal distribution in the freshwater mussel, Cristaria plicata, under laboratory conditions

Copper and zinc interaction on clearance from water and distribution in different tissues was investigated for the freshwater mussel, Cristaria plicata, under laboratory conditions. Clearance rate of Cu or Zn from water was highly dependent on exposure concentration. Interaction effect was most evident at 300 μg·L⁻¹ Cu exposure and depressed the Zn clearance rate significantly (p<0.05). However, the presence of 100 μg·L⁻¹ and 300 μg·L⁻¹ Zn hardly affected the Cu clearance rate. The 300 μg·L⁻¹ Cu presence enhanced Cu accumulation in each tissue most significantly (p<0.01), but caused Zn content to decrease in the gills by 62% (p<0.05), viscera by 49% (p<0.05) and foot by 31% (p<0.05), and increase in the mantle by 97% (p<0.05) and the muscles by 243% (p<0.05) for different Zn exposure treatments. The response of metal accumulation in various tissues of the test mussels indicated that Zn transferred from the gills, viscera and foot to the mantle and muscles might be one of the important characteristics of the Zn regulatory mechanism by leading to a narrow range of Zn concentration in the different tissues.     

Effect of light supply on CO2 capture from atmosphere by Chlorella vulgaris and Pseudokirchneriella subcapitata

Carbon dioxide (CO₂) is one of the primary greenhouse gases that contribute to climate change. Consequently, emission reduction technologies will be needed to reduce CO₂ atmospheric concentration. Microalgae may have an important role in this context. They are photosynthetic microorganisms that are able to fix atmospheric CO₂ using solar energy with efficiency ten times higher than terrestrial plants. The objectives of this study were: (i) to analyse the effect of light supply on the growth of Chlorella vulgaris and Pseudokirchneriella subcapitata; (ii) to assess the atmospheric CO₂ capture by these microalgae; and (iii) to determine the parameters of the Monod model that describe the influence of irradiance on the growth of the selected microalgae. Both microalgae presented higher growth rates with high irradiance values and discontinuous light supply. The continuous supply of light at the highest irradiance value was not beneficial for C. vulgaris due to photooxidation. Additionally, C. vulgaris achieved the highest CO₂ fixation rate with the value of 0.305 g-CO₂ L^?1 d^?1. The parameters of the Monod model demonstrated that C. vulgaris can achieve higher specific growth rates (and higher CO₂ fixation rates) if cultivated under higher irradiances than the studied values. The presented results showed that microalgal culture is a promising strategy for CO₂ capture from atmosphere.     

农田土壤自养微生物碳同化潜力及其功能基因数量、关键酶活性分析

研究农田土壤自养微生物碳同化潜力,对全面认识农田生态系统碳吸收和碳储存有着重要意义.选取6种典型农田土壤,通过14C连续标记示踪技术结合密闭系统模拟培养,量化了土壤自养微生物碳同化潜力及其向土壤活性碳库组分转化,同时结合分子生物学技术及酶学分析方法,探讨了不同土壤自养微生物细菌固碳功能基因(cbbL)丰度及关键酶(RubisCO)活性.结果表明,土壤自养微生物具有可观的CO2同化潜力,在本实验条件下,全球每年表层(0~20 cm)土壤通过自养微生物的同化作用可固定的碳为0.57~7.3 Pg.供试土壤的14C土壤有机碳(14C-SOC)含量范围为10.63~133.81 mg·kg-1,而14C可溶性有机碳(14C-DOC)、14C微生物生物量碳(14C-MBC)含量范围分别为0.96~8.10 mg·kg-1、1.70~49.16 mg·kg-1.土壤可溶解性有机碳(DOC)、微生物量碳(MBC)和SOC的更新率分别为5.07%~14.3%、2.51%~13.12%和0.09%~0.64%.土壤细菌cbbL丰度范围为2.40×107~1.9×108copies·g-1,且RubisCO酶活性(CO2/soil)范围为34.06~71.86 nmol·(g·min)-1.相关分析表明,土壤14C-SOC与14C-MBC及RubisCO酶活性均呈极显著正相关关系(P<0.01).说明土壤对大气CO2的同化作用主要是由自养微生物参与的同化过程,且较高的RubisCO酶活性意味着较高的自养微生物CO2同化潜力.     

自养微生物同化碳在土壤腐殖质组分及团聚体中的分配

采用14C-CO₂(碳同位素)连续标记技术结合室内模拟培养试验,采用土壤有机质的物理、化学分组方法,研究了不同种植方式〔P-R(盘塘水稻土)、P-U(盘塘水旱轮作土)和U-C(盘塘坡旱土)〕下14C-SOC(自养微生物同化碳)在土壤腐殖质组分和团聚体中的分配特征. 结果表明:不同种植方式显著影响自养微生物的固碳能力,P-R的自养微生物固碳能力最强〔w(14C-SOC)为38.32 mg/kg〕,约为P-U和U-C的2倍;P-R和P-U中w(14C-DOC)、w(14C-MBC)显著大于U-C中. 14C-SOC不同程度地进入了土壤的3种腐殖质组分(胡敏素、胡敏酸、富啡酸)中,其中进入胡敏素中的14C-SOC占总量的67.7%. 14C-SOC亦进入了不同粒径的土壤团聚体中,其中主要进入了Ⅲ级(0.020 mm≤粒径<0.200 mm)和Ⅱ级(0.200 mm≤粒径<2.000 mm)粒径的大团聚体中,表现出了碳汇效应;不同种植方式的土壤中,以P-R土壤各粒径土壤团聚体中w(14C-SOC)最高. 相关分析表明,全土中的w(14C-SOC)与各粒径土壤团聚体中w(14C-SOC)和胡敏酸中w(14C-SOC)均呈显著正相关.      

土壤-水体系中固/液比对溶解性石油烃吸附的影响

采用批实验的方法,研究了2种土壤在不同的固/液比（solid-to-solution ratio,SSR）条件下对溶解性石油烃（DPH）的吸附-解吸特性.结果表明,DPH在土壤中的吸附-解吸等温线符合线性方程;解吸表现出明显的滞后现象,滞后因子随SSR的升高而增加,随土壤有机碳含量（OC）的升高而减小,对于OC=1.54%的稻田土,当SSR从10.00 g·L^-1变化至75.00 g·L^-1,DPH的解吸滞后因子从1.43升高到2.21;对于OC=15.91%的黑土,当SSR从2.50 g·L^-1变化至5.00 g·L^-1,DPH的解吸滞后因子从1.18升高到1.37.说明吸附的不可逆性随SSR的升高而增强,随土壤有机碳含量的升高而减弱.另外,研究发现由吸附等温线计算得到的k_OC随SSR的升高（不可逆性的增强）而减小,在此基础上建立了固定体系中k_OC与SSR的关系模型,用于预测实际环境中DPH在土-水界面的迁移.     

亚热带稻田生态系统CO2通量特征分析

为评价稻田生态系统大气CO2的收支状况,2008-2009年江西省农业气象试验站利用涡度相关技术对稻田生态系统的CO2通量进行了为期一年的连续观测.对观测的数据进行处理和分析表明:在生长季,稻田生态系统CO2通量总体表现为负值,为CO2的汇.稻田生态系统CO2通量具有明显的日变化特征,白天净吸收CO2的量大于夜间呼吸释...     

“异养-硫自养”组合工艺去除高浓度高氯酸盐特性

通过运行双室的异养-硫自养联合反应器(下部为异养区、上部为自养区),去除高浓度高氯酸盐(ClO_4~-)废水.考察不同进水碳氯比(C/Cl)和ClO_4~-浓度条件下,ClO_4~-的降解特性及出水硫酸盐(SO_4~(2-))浓度.结果表明,通过调节进水C/Cl比由2~1,反应器在36 d快速成功启动;进水ClO_4~-浓度由250 mg·L~(-1)提升至400 mg·L~(-1)时,微生物对高浓度ClO_4~-表现出良好的耐受性,ClO_4~-的去除率始终稳定在95%以上;通过调整C/Cl比至1.2,可减少自养区ClO_4~-负荷,使出水SO_4~(2-)浓度降至250 mg·L~(-1)以下.此外,本研究证实了细菌分泌的溶解性有机物中色氨酸和酪氨酸是造成自养区出水TOC升高的原因.由于采用异养-硫自养联合工艺,控制碳源的投加,从而减少了异养区污泥的产量;同时,异养区产生碱度可以平衡自养区产生的酸度,减少了自养过程中碱度的投加;异养区产生碳酸盐也可以作为自养区的碳源,实现了异养区和自养区功能上的"互补".