Biodegradation of diesel oil in a baffled roller bioreactor

BACKGROUND: Ex situ bioremediation is a feasible and economical way to remove petroleum pollutants from contaminated soil or water. A baffled roller bioreactor was shown to be effective for biodegradation of diesel oil as a model petroleum pollutant. Microorganisms enriched from an industrially contaminated soil with heavy hydrocarbons were shown to be the best inoculum source for diesel biodegradation. RESULTS: The baffled roller bioreactor demonstrated better performance than control (roller bioreactor without baffles) or bead mill roller (control bioreactor filled partially with spherical beads) bioreactors. Biodegradation consisted of both fast and slow stages for degradation of light and heavy compounds, respectively. Among the tested temperatures ranging from 15 to 35 °C, room temperature (23 °C) was found to be the optimum temperature for biodegradation. The values of maximum specific growth rate and substrate yield (µ_max and Y_XS) for the indigenous microorganisms in the baffled roller bioreactor at room temperature were found to be 0.72 ± 0.08 h^?1 and (7.0 ± 1.0) × 10⁷ cells mg^?1 diesel, respectively. Biodegradation of diesel concentrations up to 200 g L^?1 was achieved with the highest biodegradation rate of 266 mg L^?1 h^?1 at the highest rotation rate of 45 rpm in the baffled roller bioreactor. CONCLUSION: Using indigenous bacteria enriched from industrial contaminated soil at room temperature, a baffled roller bioreactor is able to biodegrade high diesel oil concentrations at high biodegradation rates. Copyright © 2008 Society of Chemical Industry     

邻苯二酚2，3-双加氧酶在恶臭假单胞杆菌整细胞催化中的酶活检测方法

为了定量了解整细胞催化过程中关键酶酶活的变化,以恶臭假单胞菌mt-2为模式菌株,研究其在芳香族化合物降解途径中的关键酶——邻苯二酚2,3-双加氧酶（C23O）的简易检测方法。首先确立了以苯甲酸钠为唯一碳源的培养基,在优化培养条件下,达到了细胞培养和C23O同时诱导表达的目的。进而通过用磷酸缓冲溶液重悬细胞,并用分光光度法监测产物的生成速率（375 nm）,实现在整细胞的条件下,对C23O酶活进行快速准确的测量。在整细胞条件下,C23O的最适温度为35 ℃,最适pH 7.5,而在最适温度和pH下,酶与底物的动力学参数为Km=34.67 μmol•L^-1,Vmax=0.29 μmol•min^-1 •mg干细胞^-1。这些动力学参数与纯酶的相差两到三个数量级。另外通过在细胞悬液中加入0.1 g•L^-1 阳离子表面活性剂（DTAB）作用30 min后,能有效的消除细胞膜的空间障碍,增加细胞膜的通透性,从而使测量的酶活更接近于最大酶活。本研究为整细胞催化及微生物的环境修复过程中酶活的快速检测提出了简易可行的方法。     

生物修复加固石质文物研究进展

置于自然环境中的石质文物因物理、化学及生物等因素作用风化腐蚀、开裂破损而处于濒危境地,许多传统方法在应用中或因负面效应太强或因收效甚微而受局限.对结构修复加固应避免造成不可逆反应,其产物应兼具良好的相容性、有效性与耐久性,生物修复加固因应而生.综述了近年来生物修复加固方面的研究进展,并探讨了生物修复加固机理及应用研究前景.     

芳香族污染区的生物修复和监测研究的进展

生物除污可以修复被污染的土壤,这是因为微生物对有害有机化合物具有广泛的生物降解能力.生物除污及其功效方面研究的飞速发展,为检测各种微生物过程中相关关键基因的存在和表达提供了有效的分子学工具.综合分析被污染土壤中的各种基因在不同条件下的表达情况,揭示微生物的代谢情况,指示加速生物除污的环境变异.     

多自然生态技术对点源污染的感潮河道修复研究

采用生物激活技术、多功能生态浮岛与磁化抑藻曝气技术集成的多自然生态技术对江苏省太仓市樊泾河进行生态修复的现场试验。结果表明生物激活剂对存在点源污染的感潮河道具有较好的修复效果,NH3-N、TP、CODCr和叶绿素α去除率分别达到61.8%、50.4%、31.3%和75.2%以上。多自然生态技术可以发挥不同技术间的协同作用,进一步改善水质并稳定修复效果,强化对藻类的控制,明显提高水体的透明度。     

添加膨松剂和翻耕对石油污染土壤生物修复的影响试验研究

在实验室条件下,研究了添加膨松剂和翻耕对石油污染土壤生物修复的影响.结果表明添加膨松剂并翻耕土样修复48 d后,76%的TPH被降解,比不加膨松剂的处理高15%,加入膨松剂后石油烃降解速率提高了2.34倍.添加的膨松剂会迅速吸收水分,提高土壤中的含水率,改善土壤环境,提高修复效率.GC-MS分析结果表明添加膨松剂修复64 d后,峰形基本消失,出峰数由不加膨松剂的32个减少为14个,土壤中的异构烷烃、烯烃、胡萝卜烷和烷基萘的去除率接近100%,应用联合翻耕技术后,出峰数减少为10个,土壤中的异构烷烃、烯烃、胡萝卜烷、烷基萘、藿烷和甾烷完全被去除.TPH的降解率随着翻耕频率的减少而降低,最佳的翻耕频率为每天翻耕一次.     

环境中1,4-二烷污染处理技术研究进展

新型污染物1,4-二烷广泛分布于地表水、地下水和饮用水环境中。常规水处理手段对1,4-二烷难以奏效,因而其污染处理技术成为了关注的热点。本文主要针对1,4-二烷污染的处理方法进行了综述。首先对1,4-二烷的性质及分布特征进行了总结,比较了国内外已有的污染调查状况和控制标准,然后重点从物理、化学和生物法三个方面介绍了近年来1,4-二烷污染处理技术的最新研究进展,且分析了不同技术的作用机制、优缺点及可行性,并对不同技术的处理效率进行了归纳总结。文中特别指出了生物修复的难题,即氯代烃、重金属对微生物降解1,4-二烷的抑制作用和机理及改进修复技术,最后对今后的研究方向进行了展望。     

石油污染土壤菌根修复技术研究

植物根际是一个能降解土壤中污染物的生物活跃区。应用茵根修复技术对某污灌区石油烃污染土壤进行了处理。在污染土壤中种植玉米和黄豆，通过施加不同的茵剂，采取茵剂和茵根强化修复措施，在一个生长季节后，土壤中石油类污染物降解率可达53％-78％。本研究为该地区石油污染土壤的治理提供了有力的技术保证。     

城市污染水体的生物修复技术

大量未经处理的污水排入城市水体,导致城市水体严重污染。利用生物修复技术改善城市水体水质,能强化和恢复水体的自净能力,最终达到水体生态恢复。     

Microbial metabolism of xenobiotics: Fundamental and applied research

The ability of microorganisms to metabolise xenobiotic compounds has received much attention due to the environmental persistence and toxicity of these chemicals. The microbial degradation of xenobiotics is seen as a cost effective method of removing these pollutants from the environment by a process now known as bioremediation. Microbial treatment of industrial effluents is also possible. Fundamental work has revealed that a wide variety of microorganisms are capable of degrading an equally wide range of organic pollutants. Pure and mixed cultures of microorganisms have been studied and degradation is observed under both aerobic and anaerobic conditions. Breakdown products have been found during work on the degradative pathways involved and toxicological assessments using bacteria and higher organisms (fish, plants) have been used to determine the toxicity of these intermediates. Many of the degradative genes responsible for xenobiotic metabolism are present on plasmids, transposons or are grouped in clusters on chromosomes. This provides clues to the evolution of degradative pathways and makes the task of genetic manipulation easier such that new microbial strains capable of efficiently degrading pollutants can be developed. Several enzymes involved in xenobiotic metabolism have been isolated and factors affecting their activity investigated. Genetically manipulated strains or naturally isolated organisms may be used in the treatment of industrial wastes or as inocula to enhance degradation in the environment. Environmental factors, including pH, temperature, bioavailability, nutrient supply and oxygen availability have been shown to affect xenobiotic biodegradation. These factors must be optimised to obtain a satisfactory microbial treatment process. Using information gained from fundamental research, bioremediation technology has been used to detoxify different contaminated environments and the results of field studies are very encouraging.