Hydrolysis Rate of Resistant Pentosan of White Birch Wood in Sulfuric Acid of Medium Strength

The purpose of this study is to find optimal conditions for pre-hydrolysis in the new wood saccharification process with strong sulfuric acid. In the experiment, the hydrolysis rate of resistant fraction of pentosan of white birch (Shirakamba, Betula platyphylla Sukatchev var. japonica Hara) wood and the decomposition rate of xylose are measured in acid concentrations ranging from 30 to 60% at temperatures ranging from 30 to 90°C. The hydrolysis of resistant pentosan of white birch and the decomposition of xylose are the first-order reactions. The first-order reaction constant of hydrolysis of resistant pentosan, k_B min^-1, is expressed by the following empirical equations as the function of percentage concentration of sulfuric acid, C, and reaction temperature described by absolute temperature, T°K, ranging from 40 to 80°C:

where sulfuric acid concentrations range from 30 to 50%;

where sulfuric acid concentration is 60%.

The first-order reaction constant of decomposition of xylose, k₂ min^-1, is expressed by the following empirical equation as the function of sulfuric acid strength described by acidity function, H₀, and reaction temperature described by absolute temperature, T°K, in sulfuric acid concentrations ranging from 30 to 60% at temperatures within the range of 40 to 100°C.

where C is sulfuric acid strength described by acidity function, H₀.     

Study of the Ultrastructure of <Emphasis Type="Italic">Eucalyptus globulus</Emphasis> Wood Substrates Subjected to Auto-Hydrolysis and Diluted Acid Hydrolysis Pre-treatments and Its Influence on Enzymatic Hydrolysis

Dilute acid hydrolysis (DAH) and auto-hydrolysis (AU) have demonstrated to be optimal pre-treatments for the generation of biofuels from wood. Recent studies have highlighted the importance of ensuring the accessibility of cellulose enzymes during the enzymatic hydrolysis (EH) of pre-treated materials. In this work, the microscopic and nanoscopic structures of Eucalyptus globulus samples pre-treated by AU and DAH were evaluated by different techniques to understand the effect of the ultrastructure of samples on the enzymatic conversion and cellulose accessibility for bioethanol production. Microscopic techniques revealed changes in the physical characteristics of pre-treated fibers, coalescence at microscopic level, and differences in the chemical distribution of lignocellulosic components depending on the severity and type of pre-treatment. The atomic force microscopy-based nanoscopic study of samples showed differences in the effect of the pre-treatments on the ultrastructure of samples, with DAH pre-treatment producing major changes in the secondary cell wall with respect to AU samples at comparable severities, and a positive effect of the DAH ultrastructure changes to increase the EH yield.     

东宁县废柞木屑制备活性炭工艺研究

研究了氯化锌活化废柞木屑制备活性炭的工艺条件,探讨了浸渍比、活化剂浓度、活化时间和活化温度对活化效果的影响.结果表明最佳工艺条件为:浸渍比为1:2.5,活化剂浓度为60%,活化温度为650℃,活化时间为120 min.产品各项吸附指标均超过中国国家标准要求.     

Effect of Urea on the Enzymatic Hydrolysis of Lignocellulosic Substrate and Its Mechanism

Effect of hydrogen bond breaker (urea) addition on the enzymatic hydrolysis of Avicel and eucalyptus pretreated by dilute acid (Eu-DA) was investigated. Urea enhanced the enzymatic hydrolysis of Eu-DA at 50 or 30 °C when the concentration of urea was below 60 g/L, while it inhibited the hydrolysis of Avicel. Low concentration urea (<?240 g/L) had little effect on the cellulase spatial structure and its activity. But it decreased cellulase binding to cellulose surface to inhibit the cellulose hydrolysis. Meanwhile, urea obviously prevented the adsorption of cellobiohydrolase I (CBHI) on the lignin in spite of little effect on the adsorption of β-glucosidase (BGL) and two endoglucanases (EGIII and EGV) on lignin. It was proposed that urea enhanced the enzymatic efficiency of Eu-DA by decreasing the cellulase adsorption on lignin surface.     

Feulgen Hydrolysis with Perchloric Acid

In tissue fixed with Carnoy's acetic alcohol (1:3), the hydrochloric acid hydrolysis performed as part of the Feulgen reaction is optimal for only a very short period of time. When 10% perchloric acid is used as the hydrolytic agent, the same color maximum is obtained, and the optimal hydrolysis time at 25°C. extends from 12 hours to 24 hours. During this time the intensity of color does not change. The events which take place during the period of suboptimal hydrolysis are the same as diose which take place during the corresponding period of hydrochloric acid hydrolysis. Part of the decrease in ultraviolet extinction of nuclei during the first 12 hours is due to the splitting off of purine bases from the desoxyribose nucleic acid. This is consistent with the increase in the amount of Feulgen dye bound by nuclei during this period of time. Between 12 hours and 24 hours no ultraviolet absorbing material is lost from nuclei, which is consistent with the fact that during this time the Feulgen color produced remains at a maximum.     

复合诱变对米曲霉产曲酸的影响

发酵法生产曲酸还未实现大规模工业化生产的原因之一是曲酸菌种产酸率较低,本文以平展米曲霉（Aspergillus oryzae effusus)AS32为出现菌株,经UV和^60Co诱变处理,筛选获得一株高产曲酸变异株AUR163,以葡萄糖为碳源,酵母膏为氮源,32℃摇瓶和30L罐发酵培养4天,产酸达6．8g/100mL。平均生产效率为17．0g/L.d最高可达30．5g/L.d比出发菌AS32提高190％以上,这表明UV和^60Co作诱剂,可以大幅度提高米曲霉的曲酸生产效率。     

猪皮胶原蛋白水解产物中的抗氧化活性肽的分离及其氨基酸组分

利用不同蛋白酶水解猪皮胶原蛋白,根据水解产物对自由基的清除率,筛选最适蛋白酶的组合,筛选抗氧化活性较高的肽类,并进行氨基酸分析.结果表明:胃蛋白酶→木瓜蛋白酶→菠萝蛋白酶为酶解胶原蛋白的最佳组合;分离纯化得到了三种具有较高抗氧化活性的肽;氨基酸组分分析显示:P1′、P2′和P3′组分具有自由基清除作用的关键氨基酸甲硫氨酸、酪氨酸和组氨酸等.     

工业废羊毛酸解工艺条件选择

毛发蛋白盐酸水解提取胱氨酸时 ,温度、毛酸比、时间等因素影响到毛发蛋白的水解率和产品胱氨酸的总收率。通过正交试验法 ,进行了废羊毛酸解工艺参数的试验研究 ,确定了最佳酸解工艺参数为 :温度 1 0 5℃ ,毛酸比(W/V) 1∶1 .7,连续水解时间 7.0h。     

Effect of Dimethylsulfoxide on Hydrolysis of Lipase

To establish an industrially feasible reaction process, the effect of dimethylsulfoxide (DMSO) added to an aqueous solution on the hydrolysis of lipase was investigated using fluorescent substrates. Several lipases from microorganisms were improved in their hydrolysis activities against 4-methylumbelliferyl oleate by DMSO. Variation was found in the effect of DMSO depending on the species of lipase. After the high stability of the lipase from Pseudomonas fluorescens in DMSO solution was confirmed, hydrolysis by this lipase of four acyl-4-methylumbelliferones was studied kinetically at different DMSO concentrations. DMSO added to an aqueous solution increased the V_max of this lipase for a substrate with strong hydrophobicity, and decreased that value for a substrate with an opposite property. On the other hand, DMSO had a very small effect on K_m for each substrate. A fluorometric study suggested that DMSO induced a change of the chemical environment that surrounded tryptophan residues of the lipase. Such conformational change would be one of the causes of the DMSO-induced alteration of its reactive property. These results suggest that the addition of DMSO may be a novel method of ‘solvent engineering’ of this enzyme.     

氨基酸微素络合物对水稻的生物效应初探

为了配制氨基酸金属络合肥,使用其主组分进行初步田间对比试验,结果表明：氨基酸微素络合物能明显提高水稻根系活力,缩短从秧田到大田的适应期,促进植株生长,改善库源关系,增加干粒重和谷秆比,从而有效提高产量。以（ＦｅＣｕＺｎ）ＡＡ２增产效果最好,达２１．２９％,蘸根及喷施是有效施用方式。     

复方氨基酸胶囊与整蛋白型肠内营养合用对慢性支气管炎患者的应用观察

为了了解应用复方氨基酸胶囊联合整蛋白型肠内营养制剂对慢性支气管炎患者疗效的影响,将70例需进行治疗的慢性支气管炎患者随机分为治疗组和对照组.治疗组35例,在常规饮食的基础上,服用复方氨基酸胶囊联合应用整蛋白型肠内营养制剂;对照组35例,进行常规饮食,不进行肠内营养治疗.分别观察两组患者治疗前1d、治疗第20 d症状改善...     

The Temporal Distribution and Carbon Storage of Large Oak Wood in Streams and Floodplain Deposits

We used tree-ring dating and ¹⁴C dating to document the temporal distribution and carbon storage of oak (Quercus spp.) wood in trees recruited and buried by streams and floodplains in northern Missouri, USA. Frequency distributions indicated that oak wood has been accumulating in Midwest streams continually since at least the late Pleistocene, about 14,000 calibrated radiocarbon years before present (cal. BP). The median residence time of an oak bole in the study streams was 3,515 years (n = 200). More than 30% of sampled oak wood entered the floodplain sediments and stream waters within the last 1,000 years, though very few samples dated to the last 150 years. Temporal variability in the record of oak recruitment to streams suggests a potentially strong influence from shifts in climate and fluvial processes, although other possible influences are addressed. Recent human impacts on streams have altered the dynamics of oak input and sequestered carbon with unknown long-term consequences. The long duration of carbon storage (mean age = 1,960 years) in this waterlogged environment appears to be strongly limited by decreasing wood density resulting from reductions in cell wall thickness. Lack of evidence of biotic degradation may imply that wood loss is largely due to abiotic hydrolyses. These findings document a continuous and long-term form of carbon storage that is sensitive to changes in climate and anthropogenic alteration of fluvial processes.     

Isoflavones Daidzein and Genistein: Preparation by Acid Hydrolysis of Their Glycosides and the Effect on Phospholipid Peroxidation

A mixture of isoflavones was obtained by acid hydrolysis of isoflavone glycosides isolated from the products of soybean processing by successive extraction with aqueous acetone and methanol. The homogeneous isoflavones daidzein and genistein were isolated from the aglycone mixture by adsorption chromatography and identified by spectral and chromatographic methods. The effect of both isoflavones on lipid peroxidation of soy phospholipids in multilamellar vesicles was studied at various concentrations. These aglycones were found to inhibit the formation of lipid hydroperoxides and malonic dialdehyde at concentrations as low as 1 mM.     

Aroma-Forming Substances from a Culture of the Mold Fungus Penicillium roquefortiGrown on Curd

Production of aroma-forming substances by Penicillium roquefortistrains No. 31 and No. 541-A grown on curd was studied. The data showed that strain No. 541-A is the most promising producer of cheese flavor. The flavor acquired a soily scent after more than 5 days cultivation, which may hamper the use of these cultures (particularly, No. 31) in the food industry.     

Nutrients and Trace Elements Content of Wood Decay Fungi Isolated from Oak (Quercus ilex)

The presence of chemical elements and the differences in their concentration in the fruiting bodies of wood decay fungi may reflect their activity either as saprobes or parasites and the intimate physiological relation with the substrate from which they extract their nutrients. In order to test this hypothesis, we carried out a systematic sampling of eight species of wood decay fungi on oak (Quercus ilex). The data show that the concentration of some elements exhibits a very wide range of values for the species tested, which could mean that the relative content of some elements may provide clues about the nature of the substrate and, moreover, about the nutritional physiology. The comparison between the foliar analysis (FA) and the elemental content of fungi may shed light on the specific physiological behaviour of the species. Potassium is an element accumulated in fungal biomass in higher quantities than in the FA. By contrast, calcium appears in foliar analysis in much higher quantities than in fungal fruiting bodies' biomass. Concerning this element, we have also found profound differences between the two species phylogenetic groups and lifestyle. Of all elements measured, we believe that the relative accumulation of K and Ca may be related to the close connection between fungi and the substrate on which they live and may also explain their physiological role as saprobes or parasites. When the lifestyle and the systematic position of the different species sampled were compared, differences also emerged in the content of Na and Ca.     

The Amino Acid Sequence of Wood Duck Lysozyme

The amino acid sequence of wood duck (Aix sponsa) lysozyme was analyzed. Carboxymethylated lysozyme was digested with trypsin and the resulting peptides were sequenced. The established amino acid sequence had the highest similarity to duck III lysozyme with four amino acid substitutions, and had eighteen amino acid substitutions from chicken lysozyme. The valine at position 75 was newly detected in chicken-type lysozymes. In the active site, Tyr34 and Glu57 were found at subsites F and D, respectively, when compared with chicken lysozyme.