生物技术在制浆造纸中的应用

生物技术在制浆造纸方面具有广阔的应用前景.文章介绍了生物技术在制浆、漂白、脱墨、消除树脂障碍及在打浆中的应用目的、原理和工艺.生物技术不仅能改善制浆性能和成浆性质,还能从根本上减轻或减少污染物的发生量,使生态环境质量得以改善的同时,促进造纸企业走向可持续发展道路.     

微生物制剂处理制浆造纸废水的技术动向

制浆造纸废水排放量大,污染严重,需要二次处理.随着国家对环境保护的重视以及民众环保意识的不断提高,制浆造纸行业已将降低有害物质作为重要课题.生物处理是常用的制浆造纸废水处理技术,已被许多工厂采用.由于制浆造纸废水排放负荷逐年增加,开发进一步提高生物处理能力的技术显得至关重要.由于生物处理是利用细菌(酶)的生物化学反应来降低污染物,所以稳定性较差.     

对生物制浆几个问题的思考和对策

对生物制浆过程中的几个问题进行了讨论.在看到生物制浆的良好应用前景下,也不应忽视生物预处理制浆存在预处理时间较长、酶预处理化学制浆过程中酶催化效率较低的问题.并针对上述问题初步提出一些相应的改善措施.     

用活性污泥吸附助凝处理棉秆半化学浆废液

用硫酸铝钾和阳离子聚丙烯酰胺对棉秆半化学浆制浆废液进行混凝处理实验.利用生物活性污泥对有机污染物的吸附作用,将好氧生物剩余活性污泥加入到棉秆半化学浆制浆废液中,可有效提高制浆废水的絮凝处理效果.对生物污泥的加入量、吸附反应时间、反应温度、反应pH值等影响因素进行了研究和优化.结果显示,CODcr去除率达到:82.5%,比不加生物污泥提高了约18个百分点,助凝效果显著.     

对生物制浆几个问题的思考和对策

对生物制浆过程中的几个问题进行了讨论。在看到生物制浆的良好应用前景下,也不应忽视生物预处理制浆存在预处理时间较长、酶预处理化学制浆过程中酶催化效率较低的问题。并针对上述问题初步提出一些相应的改善措施。     

木质素生物调控及其对制浆的影响

原料中木质素的种类、含量与组成不同,直接影响制浆的经济性和污染程度.若能利用生物技术(反义调控)的方法调控木质素在植物体内的合成过程及其合成量,制浆的第一道工序将移到林场、农田,会真正从源头上控制与减少污染物的产生.     

制浆和造纸工厂废水的厌氧处理

20世纪80年代初期,制浆和造纸工业已经广泛应用厌氧法处理废水,目前,全世界有200多家各种类型的大型制浆和造纸工厂应用厌氧法处理废水.最常用的厌氧反应器是上流式污泥返回槽(uASB),适合于厌氧处理的废水为:用废纸制浆的造纸厂废水、机械制浆(过氧化物漂白)、半化学制浆废水以及亚硫酸盐和硫酸盐制浆厂的蒸发器冷凝液.该法优点:生产能量(生物气)、产生的生物固体最少、设备紧凑占地面积小、减少二氧化碳气体的排放.通过在线应用厌氧处理造纸车间封闭循环工艺用水,可以进一步节约新鲜水用量和减少废水排放.     

化学机械法制浆中段废水中有机污染物的降解

采用水解酸化-接触氧化法处理广西某制浆厂化学机械法制浆中段废水,出水CODCr,为352 mg/L,SS为84 mg/L.运用GCMS联用仪对制浆中段废水中的有机物进行测定,共测得有机污染物41种,其中10种有机污染物被列入美国EPA环境优先控制污染物,在进水的30种有机物中,15种有机物被完全去除.通过分析制浆中段废水有机污染物在工艺流程中相对组分变化的规律,揭示了水解酸化-接触氧化法处理制浆中段废水过程中的污染物迁移和降解规律.     

《制浆造纸工业水污染物排放标准》的特点及企业应对策略

介绍了我国制浆造纸工业技术水平及污染治理现状.分析了制浆造纸工业水污染物排放新标准(GB3544-2008)的特点,并与原有旧标准和欧美等国相关标准进行了比较.提出了制浆造纸企业在新标准实施后,在废水处理工艺和设备上应当采取的应对措施.总结了制浆造纸废水深度处理的常见方法,对新标准下废水处理的经济效益进行了分析.     

《制浆造纸工业水污染物排放标准》的特点及企业应对策略

介绍了我国制浆造纸工业技术水平及污染治理现状.分析了制浆造纸工业水污染物排放新标准(GB3544—2008)的特点,并与原有旧标准和欧美等国相关标准进行了比较.提出了制浆造纸企业在新标准实施后,在废水处理工艺和设备上应当采取的应对措施,总结了制浆造纸废水深度处理的常见方法,对新标准下废水处理的经济效益进行了分析.     

Natural pigments: carotenoids, anthocyanins, and betalains--characteristics, biosynthesis, processing, and stability

Pigments are present in all living matter and provide attractive colors and play basic roles in the development of organisms. Human beings, like most animals, come in contact with their surroundings through color, and things can or cannot be acceptable based on their color characteristics. This review presents the basic information about pigments focusing attention on the natural ones; it emphasizes the principal plant pigments: carotenoids, anthocyanins, and betalains. Special considerations are given to their salient characteristics; to their biosynthesis, taking into account the biochemical and molecular biology information generated in their elucidation; and to the processing and stability properties of these compounds as food colorants.     

Hormones, metabolites, and reproduction in Holsteins, Jerseys, and their crosses

Holsteins (HH), Jerseys (JJ), and their crosses in first (n=157) and second (n=107) lactation were used to determine if reproduction, progesterone (P4), insulin-like growth factor 1 (IGF-1), insulin, nonesterified fatty acids (NEFA), and milk production differed between genetic groups. Thirty-four cows were Holstein-Jersey (HJ) crosses, 46 were Jersey-Holstein (JH) crosses, 48 were purebred Holsteins (HH), and 29 were purebred Jerseys (JJ) in first lactation, whereas the second-lactation animals included 23 HJ, 35 JH, 35 HH, and 14 JJ. Blood samples were collected weekly for the first 10 wk postpartum. Analyses were conducted using the MIXED, chi-square, and GLIMMIX procedures (SAS Institute Inc., Cary, NC). Seasons of calving were cold (November to May) and hot (June to October) and were combined with year to form 8 year-seasons. Days open and number of services were affected by genetic group. The HH were open 169±8 d, which was greater than HJ (143±9 d), JJ (132±10 d), and JH (127±8 d). The HH had 2.4±0.1 services per pregnancy, which was greater than JH (1.9±0.1), but not different from HJ (2.1±0.2) or JJ (2.1±0.2). Concentrations of NEFA were greater in lactation 2 (0.52±0.02 mEq/L) than in lactation 1 (0.45±0.02 mEq/L) and decreased over the 10-wk period. Concentrations of NEFA were greater in the cold season except in yr 3. Insulin in lactation 1 (0.81±0.03 ng/mL) was greater than in lactation 2 (0.72±0.03 ng/mL); insulin decreased to wk 2 then gradually increased. The HJ had the greatest insulin concentrations (0.87±0.04 ng/mL) and the JJ had the lowest (0.66±0.04 ng/mL), and IGF-1 gradually increased over the 10-wk period. Milk production (actual yield in the first 305 d, not adjusted for fat and protein) was affected by genetic group, lactation number, year-season, and wk 1 insulin. The HH produced 10,348±207 kg of milk, which was greater than the HJ (9,129±230 kg), the JH (9,384±190 kg), and the JJ (7,080±240 kg). Milk production in lactation 2 (9,676±163 kg) was greater than that in lactation 1 (8,294±160 kg). The JJ (10.3±4.7%) had the highest frequency of mastitis. The chance of getting mastitis for HH (1.1±0.9%) differed from that for HJ (9.4±4.1%), JH (8.1±3.4%), and JJ (10.3±4.7%). Genetic group affected hormones and metabolites, which may partially explain differences in reproductive measures and milk yield.     

Capsicum--production, technology, chemistry, and quality. Part V. Impact on physiology, pharmacology, nutrition, and metabolism; structure, pungency, pain, and desensitization sequences

The spice Capsicum is the fruit of the cultivated species of the genus Capsicum (family, Solanaceae), C. annuum principally, and C. frutescens L. to a lesser extent. A third variety of C. annuum var. annuum fruits, the large-sized, fleshy bell capsicum is used as a fresh vegetable and valued for its aroma, color, and crisp texture, but with no pungency. This variety is not considered in this series of reviews covering primary processing, production, international trade, chemistry, and biochemistry of functional components--the red keto carotenoids, the aromatic volatiles and the pungent capsaicinoids in Parts I to III. The valid qualitative aspects correlating the specific components of capsicum and their sensory responses are critically covered in Part IV. In this the concluding part of the series of reviews, the significant preference of the spice for initially evoking an aversive response, its potent physiological and pharmacological effects, and the aspects of structure-activity relationships of the pungent stimuli of the capsaicinoids are reviewed. The beneficial effects particularly associated with long usage by some ethnic groups and its safe consumption levels, with a critical review of the studies on the gastrointestinal tract, the cardiovascular system, the sensory system, thermoregulation, nutritional impacts, and an overview of the five series is also detailed.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

Simultaneous and Direct Determination of As, Bi, Pb, Sb, and Se and Co, Cr, Cu, Fe, and Mn in Milk by Electrothermal Atomic Absorption Spectrometry

Tungsten permanent modifier with coinjection of Pd(NO₃)₂ and W–Ru permanent modifiers are proposed for the direct and simultaneous determination of As, Bi, Pb, Sb, and Se (group 1) and Co, Cr, Cu, Fe, and Mn (group 2), respectively, in milk by graphite furnace atomic absorption spectrometry. The performance of modifiers was evaluated by means of thermal behavior of analytes, sensitivity, atomic signal profile, repeatability, graphite tube lifetime, and background intensity. An air-assisted pyrolysis step was necessary to quantitative elimination of the organic matter. After methods optimization, 14 commercial milk samples were analyzed. The found concentrations of As, Bi, Pb, Sb, Se, Co, and Cr were lower than their limit of detection (2.13, 2.21, 1.49, 1.63, 2.05, 1.0, and 1.2 μg L⁻¹, respectively). Concentrations of Cu, Fe, and Mn were in the 1.58–5.74 μg L⁻¹, 9.79–49.3 μg L⁻¹, and 2.25–4.08 μg L⁻¹ intervals, respectively. The limits of detection for Cu, Fe, and Mn were 1.7, 5.3, and 2.0 μg L⁻¹, respectively. The accuracy of methods was checked after analysis of two milk standard materials. Results for Cr, Cu, Fe, Mn, Pb, and Mn were in agreement with certified values of SRMs at the 95% confidence level. Accuracy was also evaluated by addition–recovery tests and recoveries in the 86–127% range were obtained for all elements. The use of pretreat platform of graphite tubes with W or W–Ru allowed enlarging the lifetime of atomizer in 750 heating cycles.     

Polyphenols, Anthocyanins, Ascorbic Acid, and Radical Scavenging Activity of Rubus, Ribes, and Aronia

ABSTRACT: Total polyphenols, total anthocyanins, and reduced ascorbic acid were evaluated in berries belonging to the genera Rubus, Ribes, and Aronia by means of spectrophotometric and high-performance liquid chromatography (HPLC) techniques. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the fruit extracts was tested. Total polyphenols ranged from 140.6 to 888.5 mg/100 g fresh weight (FW), total anthocyanins ranged from 22.0 to 460.5 mg/100 g FW, and reduced ascorbic acid ranged from 12.4 to 153.8 mg/ 100 g FW. The average EC50 values for Aronia melanocarpa, Ribes nigrum, Ribes rubrum, Rubus fruticosus, and Rubus idaeus were 1.8, 2.8, 5.3, 6.4, and 8.2 mg FW, respectively. The results indicate that the fruits tested are good sources of natural antioxidants.     

Tyrosinase, Laccase, and Peroxidase in Mushrooms (Agaricus, Crimini, Oyster, and Shiitake)

Enzyme assays and electrophoresis were used to monitor the activity of tyrosinase, laccase, and peroxidase in Agaricus bisporus (common cultivated button mushrooms and Crimini mushrooms), Oyster, and Shiitake mushrooms. The three enzymes could be differentiated using specific substrates and inhibitors. Tyrosinase seemed to be the major phenol oxidase in the Agaricus strains, while Oyster and Shiitake mushrooms had much lower levels. Peroxidase activity was low or undetectable in all types examined. Control of enzymatic browning in different mushroom types may depend upon the distribution of different oxidases within any given type.