Strategies of Prior-Fractionation for the Graded Utilization of Lignocellulose

木质生物质是地球上最丰富的一类生物质资源,主要由碳水化合物高分子(纤维素、半纤维素)和芳族聚合物(木质素)组成。木质纤维组分的清洁高效分离,是实; 现多元化、高值化生物精炼的重要基础。本文首先讨论了基于分级利用的组分分离技术与基于制备纤维素乙醇的预处理技术的不同之处;其次,梳理归纳了五种木质; 纤维组分优先分级分离策略:纤维素优先分离,木质素优先分离,半纤维素优先分离,木质素和半纤维素优先分离以及纤维素和半纤维素优先分离;再次,基于半纤; 维素优先分离策略,对国内相关的产业化应用进行了评述;最后,对木质生物质组分分离技术的当下定位和发展前景进行了总结与展望,以期对木质生物质的三大组; 分有较全面的价值观念和利用思路,并对木质生物质精炼技术的发展提供借鉴与参考。Lignocellulosic materials contributing the large proportion to the biomass resource are mainly composed of carbohydrate polymers (cellulose, hemicellulose), and aromatic macromolecules (lignin). Pre-fractionating lignocellulose is considered as the foundational step to establish an economical and sustainable lignocellulosic biorefinery. Firstly, the distinction between lignocellulose fractionation technologies and pretreatment methods for cellulosic ethanol production is discussed. Afterwards, five prior-fractionating strategies of lignocellulose for the biorefinery process are elaborated, including cellulose-first processing, lignin-first processing, hemicellulose-first processing, lignin & hemicellulose-first processing, and cellulose & hemicellulose-first processing. And then industrial applications of hemicellulose-first processing in our country are reviewed. Ultimately, the future perspective on lignocellulose fractionation technologies are given. The aim of this review is to provide new insights into the lignocellulosic biorefinery based on the fractionating of lignocellulose.National Natural Science Foundation of China [21676223, 21506177];; Fujian Provincial Development and Reform Commission, China [2015489];; Fundamental Research Funds for the Central Universities [20720160087,; 20720160077, 20720170062]; Natural Science Foundation of Fujian Province; of China [2016J01077, 2015J05034]; Education Department of Fujian; Province [JZ160398

Cooking with active oxygen and solid alkali for the pretreating and fractionating of lignocellulose

随着环境问题的日益突出和化石资源的逐渐枯竭，对可持续生物质资源的开发利用越来越引起人们的重视。由于木质生物质具有天然的抗降解屏障，有效预处理和组分分离被认为是实现生物质高值化利用的必要步骤，也是难点所在。近年来，基于生物质资源全组分、多元化综合利用的“生物精炼”理念兴起。基于生物精炼理念和绿色化学原则，笔者团队开发了一种新型的固体碱活性氧蒸煮预处理体系，并最终发展形成了系统的各组分高值化利用工艺路线。固体碱活性氧蒸煮工艺避免使用传统工艺常用到的水溶性强碱和含硫化合物，并以廉价的水为溶剂，成本低廉，环境友好，有很好的产业化利用前景。围绕固体碱活性氧作用机制、蒸煮工艺优化和各分离组分性质进行了概括总结，以期为该工艺的深入研究和木质生物质精炼技术的发展提供经验与参考。With fossil energy resource increasingly drying up and aggravating environmental deterioration,extensive studies have recently been focused on the utilization of sustainable biomass energy.Developing an effi cient,clean method for the separation of lignocellulose components is the basis for the effective use of biomass resources,which remains a challenge.Recently,the idea of biorefi nery,aiming at comprehensive utilizing of all components of biomass,is widely recognized.Based on the notion of biorefi nery and principles of green chemistry,via cooking with solid alkali and active oxygen(CAOSA),a new process for the separation of lignocellulose components has been developed.Compared with traditional chemical pulping methods,the new process,without using strong alkali nor metal sulfi des,is novel,effi cient and environmentally friendly.This paper presents possible mechanisms involved in CAOSA process,the optimum processing conditions and properties of three isolated fractions,intended for providing reference for further study.国家自然科学基金项目(21676223、21506177)、福建省发展和改革委员会重大产业化资金项目(2015489),福建省自然科学基金(2016J01077、2015J05034)及福建省高校青年基金重点项目(JZ160398

Reductive Amination of Levulinic Acid to 5-Methyl-2-Pyrrolidone

以甲酸铵为氢源和氮源,N,N-二甲基甲酰胺为溶剂,探讨了甲酸铵直接还原胺化乙酰丙酸制备5-甲基-2-吡咯烷酮的反应途径及机理。通过实验分别考察了反应温度、反应时间、乙酰丙酸与甲酸铵的总质量分数和物质的量比、体系pH值等反应条件对5-甲基-2-吡咯烷酮得率的影响趋势。结果表明,适当提高反应温度、延长反应时间、提高乙酰丙酸与甲酸铵的物质的量比和总质量分数、增加体系pH值均有利于提高5-甲基-2-吡咯烷酮的得率。同时,考察了不同溶剂和乙酰丙酸衍生物在该反应体系中的应用,结果表明极性非质子溶剂甲酰胺、N,N-二甲基乙酰胺、二甲亚砜亦可作为该中体系反应的反应溶剂,乙酰丙酸甲酯、α-当归内酯可作为反应底物在该体系下制备5-甲基-2-吡咯烷酮。The reductive amination of levulinic acid with ammonium formate as hydrogen and nitrogen donor to synthesize 5- methyl-2-pyrrolidone（5-MeP） in DMF solvent was developed and the mechanism of this process was proposed. The effects of various reaction conditions including temperature, reaction time, mass fraction and molar ratio of levulinic acid with ammonium formate and pH value on 5-methyl-2-pyrrolidone yield were investigated. Meanwhile, different solvents and levulinate derivatives were investigated in this system. The results showed that the properly increasing temperature, reaction time, the molar ratio and total mass fraction of levulinic acid and ammonium formate,and the pH value of system could improve the yield of 5-methyl-2- pyrrolidone. The polar aprotic solvents including formamide, DMA, DMSO and levulinate derivatives,such as methyl levulinate and a-angelica lactone,could also be respectively used as solvents and substrates in this system,too.福建省自然科学基金资助项目（2016J01077）;厦门大学校长基金资助项目（20720160087

围栏封育对新疆亚高山草甸土壤夏季CO_2日排放的影响

利用静态暗箱法在中国科学院新疆巴音布鲁克草原生态站首次对具有代表性的新疆典型性亚高山草甸25年围栏内外土壤CO2日排放进行连续观测。分析了亚高山草甸土壤呼吸变化规律及其影响机制。结果表明,围栏封育后,围栏内土壤CO2日排放总量达到19.117 g.m-2.d-1,围栏外为14.465 g.m-2.d-1,围栏内土壤CO2日排放通量要比围栏外的多了32.16%。浅层土壤土壤温度(包括地表地下5 cm、10 cm土壤温度,p<0.01)与土壤CO2排放通量日变化呈显著正相关性,但15 cm、20 cm和25 cm地温与其无相关性。土壤含水量过低或者过高都会对土壤呼吸有抑制作用,分析发现,土水势在29 kPa~35 kPa时土壤CO2排放通量出现最大值。同时围栏内外土壤CO2排放通量日变化与土水势呈指数相关,其中,围栏内相关系数为0.486 6;围栏外相关系数为0.600 7

长期围栏封育对中天山三种类型草地土壤酶活性的影响[C]

本研究以新疆具有代表性的三种类型草地围栏年限为25年的土壤为研究对象,对围栏内外土壤酶活性以及与土壤环境因子之间的关系进行了相关性分析,结果表明:长期围栏封育可使围栏内的土壤酶活性高于围栏外,围栏可明显改善0～10cm土层中脲酶的活性和明显影响除亚高山草甸化草原土壤外的两类草地0～30cm土壤中蔗糖酶的活性;围栏内外土壤过氧化氢酶和碱性磷酸酶活性都较低,四种酶活性均随土壤深度增加,酶活性逐渐降低;在亚高山草原,酶活性与土壤含水量呈现出极显著的相关水平(P<0.01),而在亚高山草甸化草原,脲酶、碱性磷酸酶、蔗糖酶活性与土壤含水量也呈显著相关性(P<0.05)。酶活性与土壤有机质、速效磷、速效氮..

长期围栏封育对中天山草地植物群落特征及多样性的影响/Effects of enclosure on plant diversity and community characteristics in pasture of Middle Tianshan Mountain[J]

以中科院新疆巴音布鲁克草原生态站25年围封样地为对象,研究亚高山草原、亚高山草原化草甸和亚高山草甸化草原的植物群落特征及物种多样性。结果表明,长期围封对3种草地类型草地植被盖度、平均高度、地上生物量均有不同程度的提高,围栏内生物量与植株高度均表现为亚高山草原化草甸〉亚高山草甸化草原〉亚高山草原;3种草地类型围栏内外生物量和植被盖度差异呈极显著（P〈0.01）,且亚高山草原化草甸和亚高山草甸化草原围栏内外植物高度差异极显著（P〈0.01）。围封25年后,围栏外的群落丰富度指数和优势度指数均高于围栏内,而均匀度指数围栏内均高于围栏外

封育对中天山三种类型草地土壤酶活性的影响/Effects of Fencing Enclosure on Soil Enzyme Activities of Three Kinds in Pasture of Middle Tianshan Mountain[J]

以新疆中天山围封25 a的3种草地土壤为研究对象,以土壤酶活性分析结果为依据,采用常规统计方法对围栏内外土壤酶活性及其与土壤环境因子之间的关系进行了研究.结果表明,3种草地土壤中过氧化氢酶和碱性磷酸酶活性均较低,25 a围栏封育措施可提高围栏内的土壤表层酶活性,但围栏内外酶活性差异不显著；围栏内外酶活性均随土壤深度增加而逐渐降低；土壤酶活性与土壤微生物、土壤含水量、有机质、速效养分含量等指标关系密切,相关性显著(P＜0.05),亚高山草原化草甸酶活性与速效钾的相关性较低；活性与土壤微生物数量之间都有较高的正相关性,尤其是蔗糖酶和过氧化氢酶均与微生物数量相关性显著(P＜0.05)

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies