航空生物燃料制备技术及其应用研究进展

随着各国对温室气体排放要求的日益严格,以及化石能源的日益枯竭,近些年来航空生物燃料得到了快速发展.文中综述了航空生物燃料的发展背景、制备工艺、实际应用现状及存在的问题,重点介绍了合成气经费托合成、生物质油经催化加氢和催化裂解制备航空生物燃料的工艺路线,以及航空生物燃料的试飞和商业运营状况,论述了航空生物燃料存在的问题,并对发展航空生物燃料提出了建议.     

生物炼制——实现可持续发展的新型工业模式

当前社会经济的可持续发展正面临着能源资源短缺、生态环境恶化的空前挑战。以可再生的生物质资源替代不可再生的化石资源、实现工业模式从石油炼制向生物炼制的根本转变,是转变经济增长模式、保障社会经济可持续发展的重大战略需求。对生物炼制这一新型工业模式进行了简单介绍。     

生物质能源四十年

为应对1973年全球石油危机而发展起来的现代生物质能源已渐趋成熟,在对化石能源的替代中发挥着越来越突出的作用。回顾了生物质能源40年的发展历程,对液体生物燃料、生物天然气和固体生物燃料与发电作了专门叙述。就生物质能源与中国,以及中国发展生物质能源方略发表了自己的见解。     

纤维小体在燃料乙醇中的应用

纤维小体在木质纤维素的降解中起着重要作用。它不仅含有降解纤维素所需的各种纤维素酶系,而且组装成具有高效催化活性的多酶复合体形式。介绍了纤维小体基本结构与功能,重点概述了其在生物燃料乙醇中的应用并对纤维小体的研究提出了展望。     

中国工业生物技术的历史、现状和未来

生物经济需要构建可再生生物质资源的新型工业模式,即以生物炼制替代化石资源炼制,形成新的生产方式。生物炼制是开拓创新型技术,即采用多联产技术．实现生物质的高效综合利用。是生产能源、材料与化工产品的新型工业模式。工业生物技术是生物炼制的核心技术,是人类生物技术发展史上继医药生物技术、农业生物技术之后的第三次浪潮．     

光合菌生物制氢技术

简要分析了光合细菌产氢的主要影响因素,介绍了国内外光合细菌生物制氢技术的研究和应用现状,并对光合制氢技术的发展趋势和应用前景进行了评述。     

熔盐热裂解生物质制生物油

为探讨热裂解条件对熔盐中生物质热裂解制生物油的影响,在自行设计的反应器中,以摩尔比为7∶6的ZnCl2-KCl混合熔盐作为热裂解的热载体、催化剂和分散剂,考察了500 ℃时添加的金属盐和生物质原料的影响,并采用气相色谱-质谱仪 (GC-MS) 对生物油的主要组成进行了分析。结果表明：添加的金属盐显著影响热裂解产物得率,稀土金属盐显著提高生物油得率,降低生物油的含水率,添加摩尔分数为5.0％ LaCl3时生物油得率为32.0％,含水率为61.5％;水稻秸秆热裂解的生物油和焦炭得率较高,稻壳热裂解的气体得率较高;金属添加盐对生物油组成有较强的选择性,LiCl和FeCl2对生物质向小分子裂解具有较强的催化作用,而CrCl3、CaCl2和LaCl3对生物油二次裂解具有抑制作用。研究结果为熔盐热裂解生物质制生物油提供了参考。     

秸秆生物有机肥的施用对土壤供氮能力的影响

通过盆栽试验研究了秸秆生物有机肥的施用对土壤供氮能力的影响。结果表明,与原始秸秆相比,秸秆生物有以与尿素配合施用能明显提高土壤生物量碳,氮的含量,增幅约为3－4倍;土壤微生物量氮与土壤的供氮能力关系非常密切,前期发生强烈的微生物增殖过程,则中后期必会发生无机氮释放过程,这对作物的生长发育极为重要。同时提高了肥料氮利用率,揭示了秸秆生物有机肥配施无机氮肥改善土壤供氮能力的机理。     

生物质生物预处理研究进展与展望

木质纤维素生物质分布广、产量大、可再生,用于制备生物基能源、生物基材料和生物基化学品。木质纤维素生物质组成复杂,包含纤维素、半纤维素和木质素等,木质素与半纤维素通过共价键、氢键交联形成独特的“包裹结构”,纤维素含有复杂的分子内与分子间氢键,上述因素制约着其资源化利用。生物预处理以其独特优越性成为生物质研究的重要方面。系统阐述了生物预处理过程中木质素降解和基团修饰对纤维素酶解的影响,纤维素含量及结晶区变化,半纤维素五碳糖利用,微观物理结构的改变。进一步提出了以生物预处理为核心的组合预处理、基于不同功能的多酶协同催化体系、木质纤维素组分分级利用和新型高效细菌预处理工艺是生物预处理未来发展的重要趋势。     

生物燃料发展概况

近几年来,国际油价不断上涨,不可再生能源资源日益减少,石油能源危机即将来到。面对即将到来的能源危机,全世界都认识到必须采取开源节流的战略,即一方面节约能源,另一方面开发新能源。全球正在大力开发生物质能,太阳能、水能、风能和地热能等可再生能源并开始逐步替代矿物能源。其中,以生物质能发展最为迅速,将成为发展的重点。生物质能源的开发与利用主要包括两方面：生物质能源发电和制备生物液体燃料如生物乙醇,生物丁醇、生物柴油等。生物质液体燃料作为液体交通燃料的唯一可再生替代能源,得到了迅猛发展。[编者按]     

Is biofuel policy harming biodiversity in Europe?

We assessed the potential impacts of land-use changes resulting from a change in the current biofuel policy on biodiversity in Europe. We evaluated the possible impact of both arable and woody biofuel crops on changes in distribution of 313 species pertaining to different taxonomic groups. Using species-specific information on habitat suitability as well as land use simulations for three different biofuel policy options, we downscaled available species distribution data from the original resolution of 50 to 1 km. The downscaled maps were then applied to analyse potential changes in habitat size and species composition at different spatial levels. Our results indicate that more species might suffer from habitat losses rather than benefit from a doubled biofuel target, while abolishing the biofuel target would mainly have positive effects. However, the possible impacts vary spatially and depend on the biofuel crop choice, with woody crops being less detrimental than arable crops. Our results give an indication for policy and decision makers of what might happen to biodiversity under a changed biofuel policy in the European Union. The presented approach is considered to be innovative as to date no comparable policy impact assessment has been applied to such a large set of key species at the European scale.     

纤维燃料丁醇研究进展

随着能源危机与粮食安全问题的日趋加重,以纤维质为原料生产石油替代燃料已成为生物质能研究的重点。分析了丁醇作为燃料的优点,归纳了丁醇发酵微生物的种类与研究现状,综述了纤维原料生产燃料丁醇的研究进展,最后对我国纤维燃料丁醇的产业化优势和前景进行了分析与展望。     

CFD and kinetic-based modeling to optimize the sparger design of a large-scale photobioreactor for scaling up of biofuel production

Microalgal biofuels have not yet achieved wide-spread commercialization, partially as a result of the complexities involved with designing and scaling up of their biosystems. The sparger design of a pilot-scale photobioreactor (120 L) was optimized to enable the scale-up of biofuel production. An integrated model coupling computational fluid dynamics and microalgal biofuel synthesis kinetics was used to simulate the biomass growth and novel biofuel production (i.e., bisabolene) in the photobioreactor. Bisabolene production from Chlamydomonas reinhardtii mutant was used as an example to test the proposed model. To select the optimal sparger configuration, a rigorous procedure was followed by examining the effects of sparger design parameters (number and diameter of sparger holes and gas flow rates) on spatially averaged bubble volume fraction, light intensity, friction velocity, power input, biomass concentration, and bisabolene production. The optimized sparger design increases the final biomass concentration by 18%, thereby facilitating the scaling up of biofuel production.     

Engineering microbial biofuel tolerance and export using efflux pumps

Many compounds being considered as candidates for advanced biofuels are toxic to microorganisms. This introduces an undesirable trade‐off when engineering metabolic pathways for biofuel production because the engineered microbes must balance production against survival. Cellular export systems, such as efflux pumps, provide a direct mechanism for reducing biofuel toxicity. To identify novel biofuel pumps, we used bioinformatics to generate a list of all efflux pumps from sequenced bacterial genomes and prioritized a subset of targets for cloning. The resulting library of 43 pumps was heterologously expressed in Escherichia coli, where we tested it against seven representative biofuels. By using a competitive growth assay, we efficiently distinguished pumps that improved survival. For two of the fuels (n‐butanol and isopentanol), none of the pumps improved tolerance. For all other fuels, we identified pumps that restored growth in the presence of biofuel. We then tested a beneficial pump directly in a production strain and demonstrated that it improved biofuel yields. Our findings introduce new tools for engineering production strains and utilize the increasingly large database of sequenced genomes.     

先进生物燃料导向的脂肪酸途径合成生物学改造

化石能源日益枯竭,迫切需要寻找新型燃料。脂肪族生物燃料由于其热值高、性能好而受到广泛重视。微生物脂肪酸代谢途径是生产先进生物燃料的重要途径。文中综述了近几年基于合成生物学理念改造脂肪酸途径的进展,介绍了合成生物学在微生物柴油、中长链脂肪醇、长链烃类化合物生物合成中的应用,并展望了脂肪族生物燃料的发展方向。     

Cyanobacteria as an eco-friendly resource for biofuel production: A critical review

Cyanobacteria are photosynthetic microorganisms which can be found in various environmental habitats. These photosynthetic bacteria are considered as promising feedstock for the production of the third- and the fourth-generation biofuels. The main subject of this review is highlighting the significant aspects of the biofuel production from cyanobacteria. The most recent investigations about the extraction or separation of the bio-oil from cyanobacteria are also adduced in the present review. Moreover, the genetic engineering of cyanobacteria for improving biofuel production and the impact of bioinformatics studies on the designing better-engineered strains are mentioned. The large-scale biofuel production is challenging, so the economic considerations to provide inexpensive biofuels are also cited. It seems that the future of biofuels is strongly dependent to the following items; understanding the metabolic pathways of the cyanobacterial species, progression in the construction of the engineered cyanobacteria, and inexpensive large-scale cultivation of them.     

宏基因组技术在新型生物燃料生产酶制剂开发中的应用

随着石化燃料的日益减少,以植物生物质为原料的可再生生物燃料成为石化燃料的理想替代品。然而微生物降解生物质效率低下,是生物燃料生产过程中一大难题,因此开发效率高、稳定性强的微生物酶制剂显得尤为重要。近年来,宏基因组技术的发展为生物燃料的生产提供了多种新型酶制剂。宏基因组技术是直接提取环境样品中的总DNA,通过构建文库,筛选目的基因或功能基因的方法,在用于燃料生产的新型酶制剂的开发中发挥着重要作用。本文概述了宏基因组技术的实施策略,总结了包括纤维素酶、蛋白酶、酯酶、脂肪酶等多种酶资源开发的最新研究进展,并综合和讨论了通过酶法将木质纤维素等生物材料有效转化为生物燃料的途径,为新酶的开发提供了新思路。     

Non‐edible oil seed producing Calophyllum inophyllum ideal for India's future biofuel development

The impending climate change crisis has stimulated enormous interest in the development of biofuel globally. The supporters of biofuel hail that it is naturally carbon‐neutral whereas the critiques argue that the large‐scale plantations and production of biofuel based on Jatropha can not only strain agricultural resources but also threaten future food security. India's subsistence farmers are often faced with challenges and constraints of poverty. Foremost among the challenges are the marginal environmental conditions for agriculture often influenced by erratic rainfall, drought, poor soil quality, and unreliable irrigation water supply. In this article, we have presented a case study on the potential to use nonedible seeds from naturally occurring tree species, Calophyllum inophyllum to meet the increasing demand for biofuel production in India.     

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Microalgae have been shown as a potential bioresource for food, biofuel, and pharmaceutical products. During the growth phases with corresponding environmental conditions, microalgae accumulate different amounts of various metabolites. We quantified the neutral lipids accumulation and analyzed the swimming signatures (speed and trajectories) of the motile green alga, Dunaliella primolecta, during the lag–exponential–stationary growth cycle at different nutrient concentrations. We discovered significant changes in the neutral lipid content and swimming signatures of microalgae across growth phases. The timing of the maximum swimming speed coincided with the maximum neutral lipid content and both maxima occurred under nutrient stress at the stationary growth phase. Furthermore, the swimming trajectories suggested statistically significant changes in swimming modes at the stationary growth phase when the maximum intracellular neutral lipid content was observed. Our results provide the potential exploitation of microalgal swimming signatures as possible indicators of the cultivation conditions and the timing of microalgal harvest to maximize the lipid yield for biofuel production. The findings can also be implemented to explore the production of food and antibiotics from other microalgal metabolites with low energy costs.     

植物木质素合成调控与生物质能源利用

植物木质素生物合成调控研究已在造纸树种与饲草品质的改良中取得了许多进展。随着对木质纤维原料乙醇发酵研究的兴起,植物木质素合成调控再次成为研究热点。该文总结了目前生物质能源利用的现状,同时针对木质素在木质纤维乙醇发酵中的限制作用,综述了近年来植物木质素合成调控的研究进展,提出了今后的研究方向和内容,并展望了木质素合成调控在木质纤维乙醇发酵中的应用。