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.     

微生物降解土壤中农药残留的研究进展

研究土壤环境中农药的微生物降解是当今国际环境修复科学技术前沿领域的重要课题.从降解农药的微生物种类、降解农药的途径及机理、基因工程菌的构建等方面综述了近年来的研究进展,并提出了微生物降解农药研究领域的发展趋势和有待进一步解决的一些突出问题.     

净化剂对猪场沼液中COD的去除及其应用条件的响应面优化

利用活性炭为载体结合微生物菌株制备畜禽养殖厌氧污水(即沼液)净化剂,选取净化剂的投加量、沼液的水力停留期(HRT)和温度这3个主要影响因素,以COD降解率、BOD5降解率作为应用过程响应指标,运用响应面法(RSM)优化沼液净化剂应用条件。随着沼液水力停留期的延长,COD降解率随之升高,而BOD5降解率随之降低,采用Design-expert软件设计响应面实验可以得到两者共同的优化条件。结果表明,沼液净化剂最佳应用条件为:净化剂投加量为11 g/L、水力停留期为3.26 d、温度为26.4℃,在此条件下,利用净化剂去除沼液中COD、BOD5,沼液中COD、BOD5降解率分别为85.6%和80.3%,该研究为净化剂的应用推广提供理论参数。     

优势菌种与三重环流三相流化床耦合处理油制气厂废水

从若干种菌源中分离出降解芳香烃类和长链烷烃类化合物的高效菌种 ,将此菌种与自行设计的新型结构内循环三相流化床相结合应用于处理油制气厂排出的难降解毒性有机废水 ,分别进行了废水处理动态试验及抗冲击负荷试验 ,讨论了气水比、pH与COD去除率的关系 ,分析了酚、氨氮及各类毒性有机物的生物降解情况 .结果表明 ,反应器容积负荷为 7 16kg(CODCr) (m3·d) ,CODCr平均去除率为 79 5 % ,芳烃类化合物的去除率为 79 8% ,酚类化合物的去除率达 94 8%以上 .反应器表现出优良的抗冲击能力与高效的处理能力     

红三叶草根际区石油降解菌的筛选及降解性能

从石油污染的土壤红三叶草（nifoliumrepensLinn）根际修复区中分离筛选得到4株以原油作为惟一碳源和能源进行生长繁殖的高效石油降解菌。通过菌落形态、显微镜个体形态观察、生理生化鉴定以及菌株16SrDNA序列分析,初步鉴定4株优势降解菌分别为动性杆菌、藤黄微球菌、蜡状芽孢杆菌和短小芽孢杆菌。采用气相色谱／质谱（GC／MS）法分析4株混合菌对石油烃的降解性能。结果表明：在摇床培养条件下,混合菌54d对总石油烃的生物降解率达到90．50％,较对照高67．72％。随着生物降解时间的延长,石油组分中的正构烷烃、异构烷烃及环烷烃相对总量均呈减小趋势,而芳香烃和其他醇类、醛和酸类的相对含量则有所增加。     

染料降解菌的脱色特性、降解酶系及基因定位研究进展

本文分析了当前染料废水微生物降解优势菌的降解效果及降解机制等,介绍了三种染料降解酶的催化机理和影响因素,阐明了某些降解菌中的质粒可以控制不同结构染料的脱色。最终指出了提高菌株应用价值的两种途径：一是筛选或构建出具有多功能性的超级菌;二是在不改变染料性质的前提下,向其分子结构中引入特定取代基团,以提高其生物降解性。     

短程反硝化菌种的筛选及条件选择的研究

经对某实验室保存的反硝化混合菌液进行分离复壮,筛选到7株反硝化速率较高的菌株(编号为B06,B08,B15,B16,B19,B21).经正交试验,选出短程反硝化的最佳作用条件.分离株B08在温度25～30℃,pH值7.0～8.0,NO-2N质量浓度200 mg/L,C/N 1.4和厌氧条件下,反硝化8 h,NO-2N的去除率达到86.37%.     

有机紫外吸收剂BP-3的厌氧污泥降解特性

2-羟基-4-甲氧基二苯甲酮（BP-3）作为化学品添加剂广泛应用于防晒霜、化妆品和染色剂等个人护理品以及塑料制品,用于吸收紫外线防止皮肤晒伤、材料老化和腐蚀.经使用后BP-3随污水排放或者人类涉水活动直接或间接排放到受纳水环境.因BP-3属于疏水性化合物,进入水环境后更易于分配至污泥和沉积物等缺氧和厌氧环境,厌氧微生物降解是BP-3重要的自然消减过程.然而,目前BP-3在不同厌氧条件下的降解转化机制仍不清楚.本研究以城市污水处理厂厌氧污泥为接种体,对比分析了不同厌氧还原条件和碳源共代谢对BP-3厌氧降解转化的差异.研究结果表明,硝酸盐、硫酸盐还原条件抑制BP-3的厌氧降解,而额外添加混合碳源可促进BP-3的降解（最短降解半衰期为1.285 d）.通过对混合碳源体系厌氧菌群驯化培养,BP-3降解能力显著提高,降解半衰期缩短至0.734 d （10 mg·L^-1）.利用UPLC-QTOF-MS鉴定主要降解中间产物为2,4-二羟基二苯甲酮（BP-1）,推测其厌氧降解转化主要途径为去甲基化.筛查获得了一株BP-3高效厌氧降解单菌,通过16S rDNA测序比对确定为柠檬酸杆菌属兼性厌氧菌.     

Differential degradation of crude oil （Bonny Light） by four Pseudomonas strains

Four hydrocarbon degraders isolated from enriched oil- and asphalt-contaminated soils in Lagos, Nigeria, were tested for their petroleum degradation potentials. All the isolates were identified as species of Pseudomonas. Pseudomonas putida P11 demonstrated a strong ability to degrade kerosene, gasoline, diesel, engine oil and crude oil while P. aeruginosa BB3 exhibited fair degradative ability on crude oil, gasoline, engine oil, anthracene and pyrene but weak on kerosene, diesel and dibenzothiophene. Pseudomonas putida WL2 and P. aeruginosa MVL1 grew on crude oil and all its cuts tested with the latter possessing similar polycyclic aromatic potentials as P11. All the strains grew logarithmically with 1–2 orders of magnitude and with generation time ranging significantly between 3.07 and 8.55 d at 0.05 level of confidence. Strains WL2 and MVL1 utilized the oil substrate best with more than 70% in 6 d experimental period, whereas the same feat was achieved by P11 in 12 d period. BB3 on the other hand degraded only 46% within 6 d. Interestingly, data obtained from gas chromatographic analysis of oil recovered from the culture fluids of MVL1 confirmed near-disappearance of major peaks (including aliphatics and aromatics) in the hydrocarbon mixture.     

三菌复合发酵提高厨余真蛋白含量的研究

为改善厨余发酵的品质,增加发酵后产品蛋白含量。采用三菌复合对厨余进行发酵,探讨了三菌复合的比例、接种量、发酵时间、初始pH值对发酵效果的影响,采用L9(34)正交实验对发酵条件进行优化,并对实验菌Lc和Ydy进行16S rRNA及18S rRNA分子鉴定。结果表明,最佳发酵条件为:菌剂配比(Lc∶Ydy∶S1)为3∶2∶1,接种量为0.15%,初始pH值为5.0,发酵时间为48 h。扩大实验结果表明,在最优发酵条件下,厨余经发酵后品质得到改善,真蛋白含量由发酵前的15.42%上升到发酵后的22.47%,增加率为45.80%;发酵后大肠菌群下降到30 cfu/g以下;乳酸菌及酵母菌数量分别为1.5×109 cfu/g和6.6×108 cfu/g。分子测序及鉴定结果表明,Lc为乳酸乳球菌,Ydy为热带假丝酵母菌。