国际生物制氢相关研究的知识图谱分析

氢气是一种理想的洁净能源。生物制氢技术具有能耗低、环保等优势,是目前国内外研究的热点。从能源和环境角度考虑,发展生物制氢技术都具有重要的意义。通过ISI Web of Knowledge网络数据库检索2000~2008年8月期间生物制氢的相关研究,利用作者共引分析方法,并绘制了知识图谱。该图谱显示出此研究领域存在两大主流学术群体：群体1,其研究焦点为光解水制氢两大类,包括藻类光合制氢和蓝细菌等光合细胞制氢;群体2,其研究聚集在厌氧发酵制氢研究方面,又分为暗发酵制氢和光发酵制氢。其中厌氧发酵制氢的研究人员比较密集,说明这方面的研究是目前该领域的重点。     

厌氧发酵产氢微生物的研究进展

厌氧发酵法生物制氢在国内外受到了普遍关注, 对产氢起核心作用的微生物又成为了研究的重点课题。论述了厌氧发酵产氢微生物的研究进展, 分别对厌氧产氢细菌的发酵类型、产氢能力、菌种选育、基因改良等进行了介绍, 结合国内外研究现状, 对厌氧发酵产氢微生物研究目前存在的问题进行了总结和展望。     

厌氧发酵产氢微生物的研究进展

厌氧发酵法生物制氢在国内外受到了普遍关注, 对产氢起核心作用的微生物又成为了研究的重点课题。论述了厌氧发酵产氢微生物的研究进展, 分别对厌氧产氢细菌的发酵类型、产氢能力、菌种选育、基因改良等进行了介绍, 结合国内外研究现状, 对厌氧发酵产氢微生物研究目前存在的问题进行了总结和展望。     

新型厌氧生物技术的研发现状与前景

伴随人类社会的进步和繁荣,环境污染、能源紧张和资源短缺问题迎面而来。由于在净化水体的同时还可产生能量或电能,也可生产有价值的化学品,厌氧生物技术已成为环境工程与能源及资源工程中的一项重要技术,越来越受到人们的重视。本文分别对厌氧发酵生物制氢技术、厌氧膜生物反应器技术、微生物燃料电池技术以及厌氧生物技术生产化学品4种新型厌氧生物技术进行综述．     

生物制氢的现状与发展趋势

氢能是一种理想的能源。生物制氢技术在氢能的研究和开发中占着非常重要的位置。该文介绍了生物制氢的方法和机理,综述了国内外生物制氢的现状和发展趋势并提出了作者的看法。     

联合生物制氢方法及发展趋势

为了在生物制氢过程中最大限度提高产氢量和产氢速率,增大底物的利用率以及更好地发挥菌种间的协同作用,联合生物制氢技术成为近年来人们关注的焦点。综述了目前国内外几种联合生物制氢方法的研究现状。并从产氢机理的角度对几种联合制氢技术进行了分析比较,重点强调光合发酵和暗发酵联合生物制氢技术具有广泛的发展前景,并指出其存在的问题和未来的发展趋势。     

微生物制氢工艺优化与生物反应的调控

氢作为一种清洁高效的可再生能源日益受到人们的重视。本文从微生物制氢的条件与代谢调控方面探讨了生物制氢的最新进展。目前常用产氢细菌进行了总结,分析了细菌的培养方式和工艺方法,探讨了影响生物制氢的各种因素(pH,温度,基质,离子浓度,反应器等)。在此基础之上,阐述了分子生物学技术在生物制氢中的应用及系统代谢调控。最后,对生物制氢今后的主要研究方向及前景进行了展望。     

生物制氢及其与以海水为介质的高盐有机废水处理的耦合研究

当前,全球能源系统的主体是＂碳基能源＂——石油和煤等。这些不可再生的资源已日渐枯竭,而且大量使用会破坏地球生态系统。因此,用＂氢基能源＂逐步取代＂碳基能源＂已成为发达国家能源战略的首选目标,有的国家甚至将这一目标定在本世纪中叶。对于中国等发展中国家,大力开发生物质能等新的可再生＂碳基能源＂,同时加速发展＂氢基能源＂,争取提前进入氢能时代,才能实现可持续发展,甚至跨越式发展。制氢技术包括非生物制氢和生物制氢。非生物制氢目前已小量生产和应用,生物制氢的研究也有相当长的时间,其中影响生物制氢进入实用的主要因素是能耗和生产成本过高。因此,如果作为一个孤立的技术系统,生物制氢只能作为战略性项目。首先介绍了生物制氢的主要原理、目前限制生物制氢产业化的关键限制因子;提出了从系统论的原理出发,通过技术集成,突破生物制氢成本的＂瓶颈＂,达到环保和资源利用的双重目的,使其提前实用化;最后,重点阐述了以海水为介质的高盐有机废水的生物制氢技术的研究进展,尤其介绍我国在相关方面的研究进展。     

固定化技术在促进光合细菌产氢中的应用

氢气是一种新型的清洁高效能源,制氢技术的创新是目前研究的热点。将新型的技术及材料应用到生物制氢工艺中,从而促进生物制氢技术的产氢效率和工程应用是研究的重点之一。该文阐述了光合细菌在固定化生长条件下发酵产氢的最新研究进展,从固定化技术的原理、固定化方法的应用进展及影响因素几个方面进行了综述,详细阐述了包括包埋、悬浮载体附着生长及固定生物膜法等几种固定化方法对光发酵产氢的作用,介绍了国内外用于固定化的新型材料,并对今后的研究重点及方向进行了展望。     

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。     

微生物发酵产氢的影响因素分析*

随着环保要求的愈益严格和化石能源的日益短缺,氢作为清洁高效的可再生能源日益受到人们的重视。微生物发酵产氢可以利用可再生的生物质,符合可持续发展的要求。针对影响微生物发酵产氢的因素,总结了国内外在该领域的研究成果,重点介绍了产氢微生物、营养物、产物和工艺操作条件等方面对发酵产氢的影响,同时还阐述了以有机废弃物为基质时的发酵产氢影响因素。     

Fermentative butanol production by Clostridia

Butanol is an aliphatic saturated alcohol having the molecular formula of C(4)H(9)OH. Butanol can be used as an intermediate in chemical synthesis and as a solvent for a wide variety of chemical and textile industry applications. Moreover, butanol has been considered as a potential fuel or fuel additive. Biological production of butanol (with acetone and ethanol) was one of the largest industrial fermentation processes early in the 20th century. However, fermentative production of butanol had lost its competitiveness by 1960s due to increasing substrate costs and the advent of more efficient petrochemical processes. Recently, increasing demand for the use of renewable resources as feedstock for the production of chemicals combined with advances in biotechnology through omics, systems biology, metabolic engineering and innovative process developments is generating a renewed interest in fermentative butanol production. This article reviews biotechnological production of butanol by clostridia and some relevant fermentation and downstream processes. The strategies for strain improvement by metabolic engineering and further requirements to make fermentative butanol production a successful industrial process are also discussed.     

Metabolic Energy-Based Modelling Explains Product Yielding in Anaerobic Mixed Culture Fermentations

The fermentation of glucose using microbial mixed cultures is of great interest given its potential to convert wastes into valuable products at low cost, however, the difficulties associated with the control of the process still pose important challenges for its industrial implementation. A deeper understanding of the fermentation process involving metabolic and biochemical principles is very necessary to overcome these difficulties. In this work a novel metabolic energy based model is presented that accurately predicts for the first time the experimentally observed changes in product spectrum with pH. The model predicts the observed shift towards formate production at high pH, accompanied with ethanol and acetate production. Acetate (accompanied with a more reduced product) and butyrate are predicted main products at low pH. The production of propionate between pH 6 and 8 is also predicted. These results are mechanistically explained for the first time considering the impact that variable proton motive potential and active transport energy costs have in terms of energy harvest over different products yielding. The model results, in line with numerous reported experiments, validate the mechanistic and bioenergetics hypotheses that fermentative mixed cultures products yielding appears to be controlled by the principle of maximum energy harvest and the necessity of balancing the redox equivalents in absence of external electron acceptors.     

Bio-hydrogen production by biodiesel-derived crude glycerol bioconversion: a techno-economic evaluation

Global biodiesel production is continuously increasing and it is proportionally accompanied by a huge amount of crude glycerol (CG) as by-product. Due to its crude nature, CG has very less commercial interest; although its pure counterpart has different industrial applications. Alternatively, CG is a very good carbon source and can be used as a feedstock for fermentative hydrogen production. Further, a move of this kind has dual benefits, namely it offers a sustainable method for disposal of biodiesel manufacturing waste as well as produces biofuels and contributes in greenhouse gas (GHG) reduction. Two-stage fermentation, comprising dark and photo-fermentation is one of the most promising options available for bio-hydrogen production. In the present study, techno-economic feasibility of such a two-stage process has been evaluated. The analysis has been made based on the recent advances in fermentative hydrogen production using CG as a feedstock. The study has been carried out with special reference to North American biodiesel market; and more specifically, data available for Canadian province, Québec City have been used. Based on our techno-economic analysis, higher production cost was found to be the major bottleneck in commercial production of fermentative hydrogen. However, certain achievable alternative options for reduction of process cost have been identified. Further, the process was found to be capable in reducing GHG emissions. Bioconversion of 1 kg of crude glycerol (70 % w/v) was found to reduce 7.66 kg CO₂ eq (equivalent) GHG emission, and the process also offers additional environmental benefits.     

半纤维素水解物生物转化生产木糖醇

木糖醇在食品、医药及化工行业中有着广泛的用途而深受关注。但是,传统的化学法生产木糖醇需要一系列复杂的分离纯化步骤,过高的生产成本限制了木糖醇的使用范围。发酵工艺生产木糖醇无需木糖的纯化步骤,是取代化学合成法的一条可行工艺路线。本文着重介绍产木糖醇的微生物,酵母对木糖的同化途径,半纤维素水解物的脱毒方法,影响木糖醇发酵的工艺条件等。     

Recent progress on industrial fermentative production of acetone–butanol–ethanol by Clostridium acetobutylicum in China

China is one of the few countries, which maintained the fermentative acetone–butanol–ethanol (ABE) production for several decades. Until the end of the last century, the ABE fermentation from grain was operated in a few industrial scale plants. Due to the strong competition from the petrochemical industries, the fermentative ABE production lost its position in the 1990s, when all the solvent fermentation plants in China were closed. Under the current circumstances of concern about energy limitations and environmental pollution, new opportunities have emerged for the traditional ABE fermentation industry since it could again be potentially competitive with chemical synthesis. From 2006, several ABE fermentation plants in China have resumed production. The total solvent (acetone, butanol, and ethanol) production capacity from ten plants reached 210,000 tons, and the total solvent production is expected to be extended to 1,000,000 tons (based on the available data as of Sept. 2008). This article reviews current work in strain development, the continuous fermentation process, solvent recovery, and economic evaluation of ABE process in China. Challenges for an economically competitive ABE process in the future are also discussed.     

DsrC is involved in fermentative growth and interacts directly with the FlxABCD–HdrABC complex in Desulfovibrio vulgaris Hildenborough

DsrC is a key protein in dissimilatory sulfur metabolism, where it works as co-substrate of the dissimilatory sulfite reductase DsrAB. DsrC has two conserved cysteines in a C-terminal arm that are converted to a trisulfide upon reduction of sulfite. In sulfate-reducing bacteria, DsrC is essential and previous works suggested additional functions beyond sulfite reduction. Here, we studied whether DsrC also plays a role during fermentative growth of Desulfovibrio vulgaris Hildenborough, by studying two strains where the functionality of DsrC is impaired by a lower level of expression (IPFG07) and additionally by the absence of one conserved Cys (IPFG09). Growth studies coupled with metabolite and proteomic analyses reveal that fermentation leads to lower levels of DsrC, but impairment of its function results in reduced growth by fermentation and a shift towards more fermentative metabolism during sulfate respiration. In both respiratory and fermentative conditions, there is increased abundance of the FlxABCD–HdrABC complex and Adh alcohol dehydrogenase in IPFG09 versus the wild type, which is reflected in higher production of ethanol. Pull-down experiments confirmed a direct interaction between DsrC and the FlxABCD–HdrABC complex, through the HdrB subunit. Dissimilatory sulfur metabolism, where sulfur compounds are used for energy generation, is a key process in the ecology of anoxic environments, and is more widespread among bacteria than previously believed. Two central proteins for this type of metabolism are DsrAB dissimilatory sulfite reductase and its co-substrate DsrC. Using physiological, proteomic and biochemical studies of Desulfovibrio vulgaris Hildenborough and mutants affected in DsrC functionality, we show that DsrC is also relevant for fermentative growth of this model organism and that it interacts directly with the soluble FlxABCD-HdrABC complex that links the NAD(H) pool with dissimilatory sulfite reduction.     

Modeling and optimization of fermentative hydrogen production

Biohydrogen is a sustainable energy resource due to its potentially higher efficiency of conversion to usable power, non-polluting nature and high energy density. The purpose of modeling and optimization is to improve, analyze and predict biohydrogen production. Biohydrogen production depends on a number of variables, including pH, temperature, substrate concentration and nutrient availability, among others. Mathematical modeling of several distinct processes such as kinetics of microbial growth and products formation, steady state behavior of organic substrate along with its utilization and inhibition have been presented. Present paper summarizes the experimental design methods used to investigate effects of various factors on fermentative hydrogen production, including one-factor-at-a-time design, full factorial and fractional factorial designs. Each design method is briefly outlined, followed by the introduction of its analysis. In addition, the applications of artificial neural network, genetic algorithm, principal component analysis and optimization process using desirability function have also been highlighted.     

Fermentative biohydrogen production systems integration

Acidogenic fermentation can be used to produce hydrogen from a range of biomass sources. The effluent from this process can be utilised in a number of biological processes enabling further recovery of energy from the biomass. In this review a number of candidate technologies are assessed including conventional methanogenic anaerobic digestion, dark fermentative hydrogen production, photo-fermentation, and bioelectrochemical systems. The principles, benefits and challenges associated with integrating these technologies are discussed, with particular emphasis on integration with fermentative hydrogen production, and the current state of integrative development is presented. The various system configurations for potential integrations presented here may simultaneously permit an increase in the conversion efficiency of biomass to energy, improved adaptability to varying operating conditions, and improved stability. Such integration, while increasing system complexity, may mean that these bioprocesses could be deployed in a wider range of scenarios and be used with a greater range of substrates.