α-Amylolysis of Large Barley Starch Granules

The α-amylolysis of large (volume average 16 μm) barley starch granules was studied by measuring the amount of carbohydrates solubilizing during hydrolysis, and the changes in morphology and molecular structure of the granule residues by scanning electron microscopy, particlesize analysis, size-exclusion chromatography, X-ray diffraction, and differential scanning calorimetry. X-ray diffraction showed that, in the earlier stages of α-amylolysis, both amorphous and crystalline parts of the granules were equally solubilized. More extensive hydrolysis caused a gradual decrease in A-type crystallinity and degradation of the granular structure. Scanning electron microscopy revealed that hydrolysis proceeded through pinholes, and pitted and partially hollow granule residues were formed. The lipid-complexed amylose was less susceptible to α-amylolysis than free amylose and amylopectin. Lipid-complexed amylose started leaching out of the granule residues only after half of the starch had solubilized due to the α-amylase treatment. Even though scanning electron microscopy indicated that there were intact granules left throughout the hydrolysis, the results obtained suggested that α-amylolysis of large barley starch granules proceeded rather evenly among the granules.     

Effects of glucose,cellulose, and humic acids on soil microbial eco‐physiology

Microbial eco‐physiology in soils is regulated by substrate quality of the organic matter. This regulation was studied for a forest and an agricultural soil by the combination of activity and biomass techniques. Soil respiration was stimulated by the substrate quality in the order, humic acid < cellulose < glucose over 20 days. Concurrently, substrate addition increased the respiratory quotient (RQ), defined as the ratio of mol CO₂ evolution per mol O₂ uptake. Anabolic processes were mainly induced by glucose addition. Soil preconditioned with glucose showed a decrease in the RQ value during glucose‐induced microbial growth in comparison to non‐amended control. The decrease in the RQ value induced by preconditioning with cellulose and humic acid was lower. Glucose, cellulose, and humic acid addition modified the microbial biomass as estimated by fumigation‐extraction (FE), substrate‐induced respiration (SIR), and ATP content. Since each biomass estimate refers to specific microbial components, shifts in microbial eco‐physiology and community structure induced by substrate quality were reflected by SIR : FE and SIR : ATP ratios. The active and glucose‐responsive biomass in the forest soil which was earlier suggested as being dominated by K‐strategists was increased in the order, humic acid < cellulose < glucose.     

Efficient sugar release by the cellulose solvent-based lignocellulose fractionation technology and enzymatic cellulose hydrolysis

Efficient liberation of fermentable soluble sugars from lignocellulosic biomass waste not only decreases solid waste handling but also produces value-added biofuels and biobased products. Industrial hemp, a special economic crop, is cultivated for its high-quality fibers and high-value seed oil, but its hollow stalk cords (hurds) are a cellulosic waste. The cellulose-solvent-based lignocellulose fractionation (CSLF) technology has been developed to separate lignocellulose components under modest reaction conditions (Zhang, Y.-H. P.; Ding, S.-Y.; Mielenz, J. R.; Elander, R.; Laser, M.; Himmel, M.; McMillan, J. D.; Lynd, L. R. Biotechnol. Bioeng. 2007, 97 (2), 214- 223). Three pretreatment conditions (acid concentration, reaction temperature, and reaction time) were investigated to treat industrial hemp hurds for a maximal sugar release: a combinatorial result of a maximal retention of solid cellulose and a maximal enzymatic cellulose hydrolysis. At the best treatment condition (84.0% H3PO4 at 50 degrees C for 60 min), the glucan digestibility was 96% at hour 24 at a cellulase loading of 15 filter paper units of cellulase per gram of glucan. The scanning electron microscopic images were presented for the CSLF-pretreated biomass for the first time, suggesting that CSLF can completely destruct the plant cell-wall structure, in a good agreement with the highest enzymatic cellulose digestibility and fastest hydrolysis rate. It was found that phosphoric acid only above a critical concentration (83%) with a sufficient reaction time can efficiently disrupt recalcitrant lignocellulose structures.     

超低浓度马来酸水解玉米芯纤维素

为考察超低浓度马来酸对玉米芯纤维素的水解性能,该文采用高温液态水预处理和超低马来酸水解相结合的两步法。3,5-二硝基水杨酸(DNS)比色法和高效液相色谱法(HPLC)分析表明,第一步预处理(200℃,10min,4MPa,500r/min,液固比20:1mL/g)玉米芯可获得12.24g/L还原糖,半纤维素转化率91.76%,损失3.61%的纤维素;其残渣进行第二步酸水解(质量分数0.1%,220℃,20min,4MPa,500r/min,液固比20:1mL/g)可获得9.94g/L还原糖,纤维素转化率达95.17%,约1/3转化为糖。气相色谱-质谱联用(GC-MS)分析表明,第二步水解液中含有多种木质素降解副产物,如苯酚、苯甲酸等,带有多种活泼基团,可能与糖降解物反应,加快葡萄糖降解正反应的进行。改进反应器,使得糖降解物和木质素降解物及时排出,可提升马来酸水解性能,为马来酸在生物质水解领域的应用提供参考。     

化学预处理提高酒糟生物质酶解糖化效果

为促进酒糟生物质的酶解糖化,筛选适宜的预处理方法,以脱除木质素,提高综纤维素（纤维素和半纤维素之和）保留率为目标,研究比较了酸-超声波耦合（ultrasound-assisted acid pretreatment,UAAP）、液氨（pretreatment by soaking in aqueous ammonia,PSAA）、碱性双氧水（alkaline hydrogen peroxide pretreatment,AHPP）和酸性亚硫酸氢盐（bisulfite pretreatment,BP）4种预处理法对酒糟化学组分、结构特性和酶解得率的影响。结果表明,与其余3种方法相比,BP法处理后酒糟的纤维素和半纤维素保留率最高,分别为84.59%和84.87%,即综纤维素保留率为84.68%。与未处理酒糟（unpretreatment,UP）相比,4种方法预处理后酒糟的综纤维素酶解得率分别提高了49.12%（酸-超声波,UAAP）、55.48%（液氨,PASS）、92.79%（碱性双氧水,AHPP）和99.15%（酸性亚硫酸氢盐,BP）,其中BP法对酒糟酶解糖化的促进作用最有效。扫描电镜（scanning electron microscope,SEM）和X-衍射（X-ray differaction,XRD）结果显示,酒糟经不同方法预处理后表观结构发生了明显变化,木质纤维网络结构遭到破坏,表面呈现无规则或形状各异的膨松状态,沟壑明显,孔隙率增加,比表面积增大,有利于提高水解酶的可及性。化学组分和结构特性的变化说明酒糟的酶解得率与综纤维素的保留、木质素的去除、表面微观形貌变化以及纤维素结晶度等因素直接相关。总之,酸性亚硫酸氢盐（BP）法是适用于酒糟生物质糖化预处理的一种有效可行方法。     

Granule structure and distribution of allomorphs in C-type high-amylose rice starch granule modified by antisense RNA inhibition of starch branching enzyme

C-type starch, which is a combination of both A-type and B-type crystal starch, is usually found in legumes and rhizomes. We have developed a high-amylose transgenic line of rice (TRS) by antisense RNA inhibition of starch branching enzymes. The starch in the endosperm of this TRS was identified as typical C-type crystalline starch, but its fine granular structure and allomorph distribution remained unclear. In this study, we conducted morphological and spectroscopic studies on this TRS starch during acid hydrolysis to determine the distribution of A- and B-type allomorphs. The morphology of starch granules after various durations of acid hydrolysis was compared by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that amorphous regions were located at the center part of TRS starch subgranules. During acid hydrolysis, starch was degraded from the interior of the subgranule to the outer surface, while the peripheral part of the subgranules and the surrounding band of the starch granule were highly resistant to acid hydrolysis. The spectroscopic changes detected by X-ray powder diffraction, 13C cross-polarization magic-angle spinning NMR, and attenuated total reflectance Fourier transform infrared showed that the A-type allomorph was hydrolyzed more rapidly than the B-type, and that the X-ray diffraction profile gradually changed from a native C-type to a CB-type with increasing hydrolysis time. Our results showed that, in TRS starch, the A-type allomorph was located around the amorphous region, and was surrounded by the B-type allomorph located in the peripheral region of the subgranules and the surrounding band of the starch granule. Thus, the positions of A- and B-type allomorphs in the TRS C-type starch granule differ markedly from those in C-type legume and rhizome starch.     

纤维素超低酸水解产物的分析

基于木质纤维素类生物质水解为人类提供乙醇等能源、化工产品的重要性，该文以定量滤纸模拟生物质的主要组分－纤维素，以其超低酸水解试验得到的最佳工况下液体产物和固体残渣为研究对象，通过高效液相色谱(HPLC)结合KS-802糖柱对产物质中糖的种类进行了划分，以GC-MS对副产物进行定性，并通过扫描电镜(SEM)及热重和工业分析元素分析对固体残渣作了从表观到内部的研究，发现纤维素超低酸水解主要生成纤维四糖、三糖和二糖等低聚糖和葡萄糖及果糖，反应副产物有糠醛、羟甲基糠醛、乙酰丙酸及一些小分子酮、醛类和酸类极性化合物，水解残渣已完全改变了原始形貌，热裂解活性增强，残留物中碳和灰分含量有较大增加，最后根据分析结果探讨了纤维素超低酸水解的反应途径，为木质纤维素类生物质水解技术的规模化利用打下基础。     

甜菜细胞壁界面特征显著影响纤维素酶解效率

生物质不同器官、组织理化性质各异,这种异质性对纤维素酶解效率的影响有待深入研究。该研究以甜菜为研究对象,系统分析不同器官理化性质与酶解效率间的关系,探究细胞壁与纤维素酶的吸附特点及在酶解过程中的形态变化。结果表明,甜菜根、茎、叶酶解还原糖得率不同,根和茎的还原糖得率相近且高于叶,分别为14.64%和14.26%,叶还原糖得率较低为10.15%;酶解还原糖得率与木质素（P<0.01）、半纤维素（P<0.01）呈极显著负相关,而与比表面积（P<0.01）呈极显著正相关;甜菜根、茎、叶的薄壁组织更容易与纤维素酶结合,并且更易被降解。甜菜细胞壁界面理化特征是影响酶与底物有效吸附,进而影响纤维素酶解效率的关键因素。研究结果可为甜菜农业废弃物的利用提供参考。     

Nutritional value of Mediterranean sheep's burnet (Sanguisorba minor ssp. muricata).

A survey of compositional characteristics of the aerial part of sheep's burnet (Sanguisorba minor ssp. muricata) growing in Mediterranean French pastures has been undertaken. Investigations with scanning electron microscopy gave the morphological structure of this plant, in particular for akene ornamentation. Taxonomic characters confirmed the identification of the muricata subspecies. Moisture, ash, free sugars, cellulose, amino acids, and fatty acids of the whole aerial part were determined. Besides the major component, cellulose (20.4%), amino acid analysis showed that proteins contained mainly glutamic acid plus glutamine (0.67%) and aspartic acid plus asparagine (0.56%). The main fatty acids were palmitic (29.1%), linoleic (22.6%), and linolenic (21.4%).     

NaOH协同辐照预处理提高稻草纤维素酶解转化率

为降低预处理成本,提升稻草纤维素的酶解效果,采用NaOH协同⁶⁰Co-γ射线辐照处理稻草,研究其对稻草中纤维素酶解转化率的影响,利用扫描电镜(SEM)、红外光谱(FT-IR)分析协同预处理对稻草微观结构的影响,并通过正交试验对协同预处理条件参数进行优化。结果表明,NaOH协同辐照预处理能显著提高稻草纤维素酶解转化率,优化后的预处理条件为400 kGy辐照剂量的稻草结合2%NaOH溶液,固液比1:15,50℃条件下处理4 h,按照10 FPU·g^-1加入纤维素酶溶液,于50℃、130 r·min^-1条件下气浴恒温振荡,酶解24 h后,其稻草纤维素转化率达到78.54%±1.20%。本研究结果为农业废弃物资源能源化高效利用提供了技术支撑和理论依据。     

稻草秸秆的碱性臭氧预处理效果

为了研究碱性臭氧预处理对稻草秸秆酶水解、表观结构及成分的影响,将稻草秸秆碱性臭氧预处理后进行酶水解,对处理前后的稻草秸秆进行了扫描电镜观察及成分分析,并对处理后溶液进行了紫外光谱分析。结果表明：碱性臭氧预处理能将稻草秸秆中的木质素氧化降解为小分子的有机酸,降低了稻草秸秆中木质素的含量,提高了纤维素的含量。扫描电镜观察显示经碱性臭氧预处理过的稻草秸秆,机械组织暴露,孔隙度大,酶解的有效比表面积大。在pH值5.0、每单位底物加酶量31.2 mg/g、45℃条件下,碱性臭氧预处理稻草秸秆酶水解120 h时还原糖达到了902 mg/g,糖化率为92.57%。在相同酶解条件下,碱性预处理与未处理稻草秸秆的糖化率分别为74.90%与53.53%。碱性臭氧预处理稻草秸秆的糖化率明显高于碱性预处理与未处理稻草秸秆的糖化率。     

Determination of Plant-Available Nutrients in Two Wood Ashes: The Influence of Combustion Conditions

Wood ashes were traditionally used as a fertilizing agent from the very beginning of working land but the fertilizing quality varies according to the combusted biomass and also the industrial burning equipment. The differences between wood ash originated from fluid and classic boiler were investigated by X-ray powder diffraction (XRD), X-ray fluorescence spectrometry (XRF), differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and Mehlich 3 and deionized water extraction procedures in relation to extraction time. The results, especially of the SEM and chemical extractions, have demonstrated that the type of burning boiler determines the portions of the leachable nutrient elements. The silica and alumina ash content conducted by the elevated temperature transforms the main proportion of calcium and potassium into the insoluble feldspars. Due to this effect only a small amount of nutrients could be released and served as a fertilizing matter.     

微生物预处理油菜秸秆对提高沼气产量的影响

为研究微生物预处理技术对秸秆发酵制沼气的影响,采用混合菌剂对油菜秸秆进行预处理,利用红外光谱分析仪和扫描电子显微镜对预处理前后的秸秆进行分析。结果表明,混菌共发酵预处理11 d后油菜秸秆的纤维素、木质素、半纤维素降解率分别达到了37.4%、28.9%和29.9%。混菌共发酵预处理使油菜秸秆的木质纤维素内部结构发生较大改变,产生很多裂缝和空洞。以油菜秸秆为原料进行沼气发酵试验,发现预处理后的秸秆日产气量最高峰值较未处理的提高了37.6%,累计产气量提高了17.8%。由此可见,通过混合菌剂降解油菜秸秆中的纤维素、木质素和半纤维素,可促进秸秆生物质转化为沼气。     

新型肥料对棉花产量及土壤物化性质的影响

为了探究PPMn型水溶肥混合棉粕腐植酸肥施用对棉田土壤和棉花产量的影响,通过红外光谱和扫描电镜分析两种新型水溶肥的官能团特征和外观特征,并利用田间小区试验研究了两种新型水溶肥对棉田土壤物理性质及团聚体、棉花产量和肥料利用率的影响。结果表明:施用棉粕腐植酸肥(H)、PPMn型水溶肥(P)和两种新型水溶肥混合(HP)对改善土壤物化结构和提升棉花产量均优于常规水溶肥(S)和不施肥(CK),其中HP处理效果最好。HP处理使土壤容重降低8.15%,土壤孔隙度增加7.49%,有效降低了0.25mm土壤团聚体所占比例,显著提升氮磷钾的农学利用效率,棉花产量相对于其他处理增加7.5%~41.0%。     

Bestimmung cellulosisch und nichtcellulosisch gebundener Neutralzucker in Bodenhydrolysaten mit Hilfe von Hochleistungsdünnschichtchromatographie

Determination of cellulosic and noncellulosic neutral sugars occurring in soil hydrolysates by means of high-performance thin-layer chromatography Analytical methods for soil samples are described, which allow the differentiation between monosaccharides bound in cellulosic and noncellulosic polysaccharides of the plant cell wall. The four step procedure includes hydrolysis of total polysaccharides (72 % H₂SO₄, 2N H₂SO₄), hydrolysis of the noncellulosic fraction (2N trifluoroacetic acid), separation of the monomers by high-performance thin-layer chromatography (HPTLC) and scanning of the plates for quantification. The amount of cellulose can be calculated by the difference of total glucose and glucose hydrolyzed by trifluoroacetic acid. Hydrolysis of soil samples by trifluoroacetic acid is a simple method for the determination of noncellulosic cell wall polysaccharides. Losses of sugars during the whole analytical procedure (hydrolysis, separation by HPTLC and quantification) are below 10 % for all sugars studied (galactose, glucose, mannose, arabinose, xylose). Standard deviations do not overstep this value, too. By HPTLC a large number of samples are chromatographed together; therefore, the total analysis time per sample is very short. As example the depth functions of hydrolyzed sugars in a Lithic Borofolist are discussed.     

Biosorption of Toxic Metals by Water Lettuce (<Emphasis Type="Italic">Pistia stratiotes</Emphasis>) Biomass

Adsorption isotherms were constructed to evaluate the potential use of water lettuce (Pistia stratiotes) dry biomass for the biosorption of zinc and cadmium. One gram of dry biomass of this plant was treated with five increasing doses of zinc (1.8, 18, 50, 79, and 105 mg L^?1) and four doses of cadmium (0.01, 0.1, 1, and 10 mg L^?1), for nine collection times (1, 3, 6, 12, 24, 36, 48, 60, and 72 h). The levels of these metals were determined by atomic absorption spectrophotometry. To evaluate changes in the surface morphology of the dry biomass, scanning electron microscopy (SEM) images were taken of the samples subjected to the greatest contamination, and these were compared with the images of the samples without zinc and cadmium (control). The ISOFIT software was used to select the isotherm model that best fit the biosorption of metals by water lettuce dry biomass. The linear model was determined to be the best-fitting isotherm model, because it had the lowest corrected Akaike information criterion (AICc) value and a Akaike weight (AICw) value closest to one, which indicates the high affinity of the biosorbent for the adsorbates evaluated. The results for both metals demonstrated greater than 70% reductions in the concentrations of the metals in the contaminated solutions. The SEM images indicated changes in the morphology of the contaminated biomass, thus demonstrating the biosorption mechanisms and confirming the potential of the dry biomass of this plant for use in the remediation of solutions contaminated with zinc and cadmium.     

含多种天然组分保水剂的制备及其对KH2PO4的缓释效果研究

以天然产物腐植酸(HA)、羧甲基纤维素钠(CMC)、蒙脱土(MMT)为复合组分,丙烯酸为聚合单体,使用水溶液聚合法制备了一种含有多种天然组分的环境友好型保水剂,用红外光谱、扫描电镜和热重/差示扫描量热分析对保水剂的结构和热性能进行了表征。分析了聚合工艺条件如HA、MMT、CMC和交联剂用量对保水剂吸水倍数的影响规律。保水剂在蒸馏水和0.9%NaCl溶液中的吸水倍数分别为801倍和87倍。探索了保水剂对磷酸二氢钾(KH2PO4)的负载和缓释性能,结果表明,MMT的加入以及适度的交联可显著提高保水剂对KH2PO4的负载率,并有效减慢其对KH2PO4的释放率,HA可明显提高保水剂的吸水性能,但对KH2PO4的负载和释放影响不大。     

氨基酸部分替代硝态氮对小白菜产量、品质及根际分泌物的影响

采用局部无菌水培方法,研究了氨基酸部分替代硝态氮对小白菜产量、品质及根际分泌物的影响。结果表明:与单一硝态氮处理相比,20%氨基酸部分替代硝态氮处理小白菜产量下降,硝酸盐及可溶性淀粉含量也显著降低,其中以20%谷氨酸（Glu）处理最低,分别为1490.8 mg/kg、1.77 mg/g;提高了小白菜全氮、可溶性蛋白、可溶性糖、游离氨基酸的含量,改变其根系形态结构及根系活力;同时,20%甘氨酸（Gly）、20%混合氨基酸(AAS）处理显著提高根系分泌物中铵态氮、游离氨基酸、总有机碳及总氮、可溶性蛋白的含量,根系分泌物中有机氮占总氮的百分比在Gly、Glu、AAS处理中分别提高了5.6%、11.2%、12.8%。表明氨基酸部分替代硝态氮可改善小白菜的品质,其生物量与各根系分泌物呈明显的负相关(0.7     

Chemical structures of corn stover and its residue after dilute acid prehydrolysis and enzymatic hydrolysis: insight into factors limiting enzymatic hydrolysis

Advanced solid-state NMR techniques and wet chemical analyses were applied to investigate untreated corn stover (UCS) and its residues after dilute acid prehydrolysis (DAP) and enzymatic hydrolysis (RES) to provide evidence for the limitations to the effectiveness of enzyme hydrolysis. Advanced solid-state NMR spectral-editing techniques as well as 1H-13C two-dimensional heteronuclear correlation NMR (2D HETCOR) were employed. Our results indicated that dilute acid prehydrolysis selectively removed amorphous carbohydrates, increased aromatic CH/other protonated -C═C- and enriched alkyl CH and CH2 components. Cinnamic acids were increased, and proteinaceous materials and N-containing degradation or condensation compounds were absorbed or coprecipitated in RES. 2D HETCOR experiments indicated a close association between lignin and the residual carbohydrates. Ketones/aldehydes were not detected in the DAP, in contrast to a report in which an appreciable amount of ketones/aldehydes was generated from the acid pretreatment of a purified cellulose in the literature. This suggested that acid pretreatment may modify the structure of purified cellulose more than biomass and that biomass may be a better substrate than model biopolymers and compounds for assessing structural changes that occur with industrial processing. On the basis of NMR and wet chemical analyses, we found the following factors could cause the limitations to the effectiveness of enzymatic hydrolysis: (1) chemical modification of carbohydrates limited the biologically degradable carbohydrates available; (2) cinnamic acids in the residue accumulated; (3) accessibility was potentially limited due to the close association of carbohydrates with lignin; and (4) proteinaceous materials and N-containing degradation or condensation compounds were absorbed or coprecipitated.     

猪胆石显微结构与化学成分的研究

采用扫描电镜和化学分析方法，对猪胆石进行观察与分析。结果表明：胆石表面形态各异，并有许多洞穴；剖面可见形态各异的、并失去固有单体形状的晶体所组成，其中可见有缝隙或孔洞，说明胆石不是实心体；胆石中含有胆固醇５４．２％，胆汁酸１２．４％，胆红素０．８２％，钙２．７６％，镁１．８５％，锌８５０ｍｇ／ｋｇ，铜３２０ｍｇ／ｋｇ，属一种混合性胆石。