二氧化碳减排产柴油微藻培养体系研究进展

污水资源化、二氧化碳减排及微藻生物柴油是当前能源与环境领域的前沿课题。以下围绕污水及烟道气资源化培养产油微藻的培养体系,就藻种、营养条件、培养方式、培养环境及微藻生物反应器等影响产油微藻培养的因素研究进展进行了综述。在综述的基础上提出：由于微藻具有特殊营养方式,通过藻种筛选、微藻营养条件和培养环境的优化以及高效光生物反应器和生产工艺等的创新,可利用污水进行产油微藻生产,以获得生物柴油等高附加值产品,实现微藻生物能源、污水资源化处理和CO2减排三者高度耦合的产油微藻生产体系,从而减少微藻培养费用及污水处理费用,因此,该体系具有重要的环境、社会、经济价值和商业化应用前景。     

产生物柴油微藻培养研究进展

石油的大量使用会导致能源枯竭和温室气体（CO2）排放的增加。为了实现经济和环境的和谐发展,必须使用可再生能源代替石油。可再生能源使用后不会造成温室气体排放的增加。生物柴油是一种理想的可再生能源, 能满足以上要求,所以近年来得到迅速发展。微藻是一种主要利用太阳能固定 CO2,生成制备生物柴油所需油脂的藻类。因此以微藻油脂为原料转化成的生物柴油是石油理想的替代品。简要介绍了产油微藻的种类和微藻油脂的合成,较详细地阐述了微藻自养培养、异养培养、生物反应器、工程微藻的最新研究进展,并初步展望了微藻产油研究的未来发展方向。     

微藻减排CO2制备生物柴油的研究进展

碳减排与可再生能源的开发利用是研究可持续发展的热点,而微藻在此方面具有巨大优势.利用微藻减排CO2合成生物柴油生产原料油脂,对于解决能源短缺和全球变暖具有重大战略意义.将碳减排与微藻生物柴油的制备方法相结合,对微藻转化CO2合成生物油脂的机制,微藻油脂积累的影响因素以及国内外在工业上的研究概况等方面进行综合归纳和评述,并对微藻生物油脂的发展前景进行了展望.     

利用微藻固定烟道气中CO2的实验研究

为获得能适合于烟道气条件下生长的微藻 ,找到一种高效的温室气体固定的方法 ,利用配置烟道气 (CO2 和O2 的浓度分别为 15 %和 2 %)驯化稻田微藻混合试样 ,分离出对高浓度CO2 条件有很强适应力的微藻ZY 1,并研究了在不同培养条件下微藻ZY 1的生长情况 .微藻ZY 1在CO2 浓度从 10 %～ 15 %的范围内有较高生长力 ,在CO2 浓度为 10 %时 ,生长最好 .微藻ZY 1对温度、气体流速、pH值等物理条件也有很宽的适应范围 ,在温度为 2 5～ 30 .C、流速为 0 2 5～ 0 75L·min-1、pH4～ 6范围内 ,生长基本稳定 .在培养条件为 10 %CO2 、2 5 .C、pH5 0时 ,微藻ZY 1的生长率最高 ,CO2 的固定率平均值为 0 397%.可以认为 ,利用该藻固定烟道气温室气体具有一定的可行性 .     

微藻生物柴油的发展

微藻生物柴油是一种具有较大发展潜力的可再生能源,与动、植物为原料制备的生物柴油相比,它有不占用耕地、产油效率高等优点。目前,微藻生物柴油在国内外都有很大发展,产业化的进程也在逐步推进。介绍了高油脂含量微藻的种类、微藻合成油脂的机理研究、微藻的培养技术及微藻生物柴油的产业化现状,并对微藻生物柴油发展中的一些问题进行了分析。     

用于生物柴油的产油微藻研究进展

在新能源开发过程中,人们注意到利用微藻生产可再生能源.微藻具有光能自养能力,在吸收储存太阳能的同时,还能固定CO2、减轻温室效应.相比于陆生植物,微藻具有生长快、光合作用效率高、节省土地、可以工业化生产等优点.一些微藻在一定的条件下可以以积累油脂的方式贮存太阳能,人们可以利用油脂来生产生物柴油.目前微藻油脂的产量还较低,成本较高,用微藻油脂生产生物柴油还不具有竞争力.要使微藻油脂生物柴油具有现实意义,必须保证微藻高效率、低成本生产油脂.     

利用基因工程技术提高微藻油脂含量的研究进展

利用微藻油脂制备生物柴油因具有重要的战略意义而受到世界各国的重视,成为近年来的研究热点。利用微藻制备生物柴油具有生长周期短、易于大规模培养、能大量吸收CO2及不占用耕地等优点。但是,由于对藻类油脂合成代谢中的调节机制了解不多,导致微藻基因组研究相对滞后,极大地限制了微藻生物能源的大规模开发和利用。随着现代生物技术的发展,通过基因工程、代谢工程等方法调控微藻脂类的合成代谢,提高藻类含油量和生物量已成为可能。概述了微藻中油脂的合成代谢,归纳总结利用基因工程技术提高微藻油脂含量的研究进展,为获得含油量高的工程微藻及微藻制备生物柴油提供技术储备。     

产油嗜碱绿球藻MC-1的烟气适应性

为了降低微藻产油成本和减少温室气体的排放,利用煤炭烟气培养一株具有pH快速漂移和高碱适应特性的产油微藻Chlorococcum alkaliphilus MC-1.首先于15L光生物反应器中分三组(空白组、CO2组和烟气组)进行小体积培养实验,然后在24 m2开放式跑道池中进行放大培养,研究了微藻MC-1对烟气培养的适应性.结果表明,在光生物反应器培养实验中,烟气组的最高生物量浓度、生长速率、藻体总脂含量和CO2固定速率分别为:(1.02±0.07) g/L、(0.12±0.02) g/(L·d)、(37.84±0.58)％和(0.20±0.02) g/(L·d),比CO2组分别提高了36％、33.33％、15.34％和33.33％.在开放式跑道池培养实验中,烟气与纯CO2的培养效果相似,烟气培养下的最高生物量浓度、生长速率、藻体总脂含量和CO2固定速率分别为:147.40 g/m2、14.73 g/(m2·d)、35.72％和24.01 g/(m2·d);烟气培养产出的藻粉中有毒重金属Pb、As、Cd和Cr的含量均低于国家限量标准.实验同时测定了烟气培养下藻液对烟气中CO2、NO和SO2的吸收效果,结果显示,在光生物反应器和开放式跑道池培养中此三种气体的平均吸收率均高于以往研究结果.上述结果说明,该藻能适应烟气培养条件,耦合微藻MC-1产油与烟气减排的室外放大培养是可行的.     

微藻生物能源的产业化进程及其在CO2减排中的应用进展

基于微藻能源的第三代生物燃料,是一种通过微藻的光合作用积累生物量和油脂而获得的新型清洁生物能源。微藻是由阳光驱动的细胞工厂,它可以在常温常压下实现对CO2的高效吸收,通过微藻细胞高效的光合作用,将光能转化为脂肪或淀粉等碳水化合物的化学能,并释放出O2。将就生物能源、微藻生物能源及其在CO2减排中的应用和产业化进程进行总结和展望。     

一株耐NaHCO3高含油绿藻的筛选鉴定

正传统化石能源储量日益减少,化石能源燃烧后产生的二氧化碳是全球变暖的主要元凶,因此,能够替代传统化石燃料、可再生的新型能源受到广泛的关注,生物柴油便是较为理想的新型能源之一[1]。虽然油料作物、废弃油脂等为生物柴油生产提供了部分原料,但其成本、规模及可持续性受多种因素的制约[2]。目前,利用光合自养的微藻生产生物柴油的潜在价值已经得到广泛的认可,微藻生物柴油技术在减少CO_2排放、大规模培养、产油效率等方面的优势日益突显[3]。微藻生物柴油的生     

一株红假单胞菌的分离及对Cu2+的去除

【背景】重金属污染对环境和人类的健康构成了重大威胁,因此,重金属污染的治理迫在眉睫。生物治理因成本低、处理效果好和无二次污染等优点,在处理重金属污染时被优先选择。【目的】从辽河入海口深13 m的水体中,利用紫色非硫细菌富集培养基筛选产色素能力强并对高浓度Cu~(2+)有高效去除能力的菌株。【方法】采用形态学、生理生化特性和分子生物学方法鉴定菌种;采用二乙基二硫代氨基甲酸钠分光光度法测定Cu~(2+)的含量。【结果】鉴定菌株为红假单胞菌属,将其命名为Rhodopseudomonas sp. gh32。菌株gh32的最适生长温度和最适pH分别为30°C和7.0,其在pH 5.0-10.0范围内可正常生长,在3 mmol/L的CuSO4溶液中能够正常生长,能利用葡萄糖、甘露糖和果糖等单糖和硫化氢。菌株gh32在24h内对Cu~(2+)的去除率均在99%以上,处理能力为1 331 g/g干菌重或167.6 g/g湿菌重。【结论】菌株gh32对Cu~(2+)具有较强的耐受性和很好的去除效果,是治理含Cu~(2+)废水的潜力菌株。本研究为生物治理重金属废水提供了支持。     

新月藻生物吸附Pb2+影响因素的研究

对新月藻生物吸附Pb^2 的影响因素作了初步研究,实验表明,在新月藻的指数生长期和静止期加入Pb^2 时,Pb^2 的去除率较高;当藻细胞密度一定时,随着Pb^2 浓度的增加,其去除率增大,当Pb^2 浓度一定时,随着藻细胞密度的增加,新月藻对Pb^2 的去除率增大;pH对Pb^2 吸附影响不大,在pH5-9的范围内,Pb^2 去除率在60%以上。     

小球藻吸附水中Pb2+影响因素的初步研究

对小球藻生物吸附水中Pb2 + 的影响因素作了初步研究。实验表明 :在小球藻处于指数生长期和静止期时加入Pb2 + ,去除率达 6 0 %以上 ;当藻细胞密度一定时 ,随着Pb2 + 浓度的增加 ,Pb2 + 的去除率增大 ;当Pb2 + 浓度一定时 ,随着藻细胞密度的增加 ,小球藻对Pb2 + 的去除率增大 ,藻细胞密度为 1 2 9× 10 8个 /ml时 ,去除率可达 92 82 % ;加强光照可以促进小球藻对Pb2 + 的吸附 ;在pH值为 5～ 10的范围内 ,pH对Pb2 + 吸附影响不大 ,较佳的pH值在 7左右。实验最佳条件的去除率在 90 %以上 ,去除效果较好。     

光生物反应器脱除空气中CO2的模型研究

微藻光生物反应器具有脱除空气中CO_2能力。从光生物反应器构型、进气流速、混合传质,及微藻光合/呼吸速率等方面,探讨气升式光生物反应器脱除空气中CO_2效果,提出了时间离散化和集中参数法两种分析方法。运用集中参数法建立了气升式柱型光生物反应器脱除CO_2的数学模型,模拟了藻液中溶氧浓度(DO)、pH随时间的变化情况,及进气CO_2浓度影响,预测并验证了光照条件下出气CO_2、O_2浓度的变化趋势。模拟结果和实验数据基本吻合,所提出的模型对光生物反应器的优化设计、微藻的高密度培养,及CO_2去除能力预测具有参考意义。     

Nutrient removal in an A2O-MBR reactor with sludge reduction

In the present study, an advanced sewage treatment process has been developed by incorporating excess sludge reduction and phosphorous recovery in an A2O-MBR process. The A2O-MBR reactor was operated at a flux of 17 LMH over a period of 210 days. The designed flux was increased stepwise over a period of two weeks. The reactor was operated at two different MLSS range. Thermo chemical digestion of sludge was carried out at a fixed pH (11) and temperature (75 °C) for 25% COD solubilisation. The released phosphorous was recovered by precipitation process and the organics was sent back to anoxic tank. The sludge digestion did not have any impact on COD and TP removal efficiency of the reactor. During the 210 days of reactor operation, the MBR maintained relatively constant transmembrane pressure. The results based on the study indicated that the proposed process configuration has potential to reduce the excess sludge production as well as it didn’t detoriated the treated water quality.     

The probiotic properties of Lactobacillus buchneri P2

Aims: To isolate new lactobacilli strain with cholesterol‐lowering effect and analyse its probiotic properties and possible mechanisms of cholesterol removal. Methods and Results: The strain with cholesterol‐lowering effect was isolated from pickled juice. The acid and bile tolerance and antimicrobial activity were tested. The free cholalic acid, the cholesterol in supernatant fluid, washing buffer and cell extract, the cholesterol removed by growing, dead and resting cells were quantified. The isolated strain with high cholesterol‐reducing rate of 43·95% was identified as Lactobacillus buchneri (Lact. buchneri) P2. It had acid and bile tolerance and antimicrobial activity. Moreover, it could remove cholesterol via coprecipitating with deconjugated bile salts, assimilating and adsorbing by cells. And the assimilation was considered to be the main reason of cholesterol removal. Conclusions: The isolated Lact. buchneri P2 showed probiotic properties of cholesterol reduction, acid and bile tolerance and antimicrobial activity and could remove cholesterol via different ways. Significance and Impact of the Study: A new strain of Lact. buchneri P2 with efficient cholesterol‐reducing ability was isolated to provide species diversity of lactobacilli for functional dairy products. And the possible mechanism of cholesterol removal by Lact. buchneri was discussed.     

Perchlorate and nitrate remediation efficiency and microbial diversity in a containerized wetland bioreactor

We have developed a method to remove perchlorate (14-27 microg/L) and nitrate (48 mg/L) from contaminated groundwater using a wetland bioreactor. The bioreactor has operated continuously in a remote field location for more than 2 yr with a stable ecosystem of indigenous organisms. This study assesses the bioreactorfor long-term perchlorate and nitrate remediation by evaluating influent and effluent groundwater for oxidation-reduction conditions and nitrate and perchlorate concentrations. Total community DNA was extracted and purified from 10-g sediment samples retrieved from vertical coring of the bioreactor during winter. Analysis by denaturing gradient gel electrophoresis of short, 16S rDNA, polymerase-chainreaction products was used to identify dominant microorganisms. Bacteria genera identified were closely affiliated with bacteria widely distributed in soils, mud layers, and fresh water. Of the 17 dominant bands sequenced, most were gram negative and capable of aerobic or anaerobic respiration with nitrate as the terminal electron acceptor (Pseudomonas, Acinetobacter, Halomonas, and Nitrospira). Several identified genera (Rhizobium, Acinetobactor, and Xanthomonas) are capable of fixing atmospheric nitrogen into a combined form (ammonia) usable by host plants. Isolates were identified from the Proteobacteria class, known for the ability to reduce perchlorate. Initial bacterial assessments of sediments confirm the prevalence of facultative anaerobic bacteria capable of reducing perchlorate and nitrate in situ.     

废水自养生物脱氮技术研究进展

基于短程硝化和厌氧氨氧化的自养脱氮工艺是生物脱氮领域研究的热点,它的发现为低碳氮比废水的处理提供了新的思路。近些年来,人们陆续开发了SHARON、ANAMMOX、CANON、OLAND等自养生物脱氮工艺,进一步推动了高效、低耗脱氮技术的开发和研究。本文从工艺原理、特点等方面,对自养生物脱氮工艺的国内外研究状况进行了总结和对比,并提出了存在的问题及发展方向。     

Assessment of iodine‐treated filter media for removal and inactivation of MS2 bacteriophage aerosols

Aims: To investigate the performance of an iodine‐releasing filter medium for use as a protective device against airborne pathogens. Methods and Results: The filter’s physical and viable removal efficiencies (VRE) were investigated with challenges of MS2 bacteriophage aerosols, and the infectivity of MS2 collected on the filter was analysed. To test a proposed inactivation mechanism, media containing thiosulfate or bovine serum albumin (BSA) were put in impingers to quench and consume I₂ released from the filter. In direct plating experiments, treated filters presented significantly higher VREs than did untreated filters; however, collection in excess BSA decreased VRE by half and in thiosulfate the apparent VRE decreased drastically. No significant difference in infectivity of retained viruses on treated and untreated filters was observed at the same environmental condition. Conclusions: Evidence presented herein for competition by dissolved I₂ in infectivity assays supports a mechanism of induced displacement and capture of I_2. It also requires that dissociation of iodine from the filter and capture of iodine by MS2 aerosols as they pass through the filter be factored in the design of the assessment methodology. The filter’s strong retention capability minimizes reaerosolization but also makes it difficult to discriminate the antimicrobial effect at the surface. Significance and Impact of the Study: This study shows the direct plating assay method to be sensitive to interference by iodine‐releasing materials. This requires reevaluation of earlier reports of VRE measurements.     

A high–performance compact filter system treating domestic wastewater

A new compact wastewater treatment system for use in single houses has been constructed in eastern Norway. The system is based on the principles of sub-surface flow constructed wetlands using various types of Filtralite as filter media. It consists of a septic tank followed by an aerobic biofilter succeeded by an upflow saturated filter. The aerobic biofilter is essential to remove organic matter and achieve nitrification, while the upflow filter polishes the wastewater and removes microorganisms and phosphorus. During the first 3 years of operation, the system has show stable and high removal with the following average values measured from the outlet of septic tank to the outlet of the upflow filter: 97.0%-BOD₇, 30%-N, 99.4%-P, and 70.8%-SS. No Escherichia coli or somatic coliphages have been detected in the effluent. Due to considerable removal of organic mater, nutrients, and pathogens, the effluent will not negatively affect water and soil ecosystems. The system requires low maintenance and is designed to remove phosphorus for 5 years before renewal of the upflow filter media. When saturated with phosphorus, the media is a suitable fertilizer for plant production.