木质素酚醛树脂的研究进展

综述酚醛树脂发展史、种类、合成机理及进展,由于木质素分子中有酚羟基和醛基,因此使用木质素既可改善胶粘剂的性质,又可节约苯酚的用量,降低甲醛释放量,达到废物利用与保护环境的目的。重点论述了新型改性酚醛树脂的研究进展,尤其木质素改性酚醛树脂,并对新型酚醛树脂复合材料的发展方向和前景作了展望。     

棉籽渣粕制备L—精氨酸盐酸盐

<正> 精氨酸(Arginine)是组成蛋白质的基本单位之一,它参与生物体内的新陈代谢过程中的乌氨酸循环以及其它生理机能。因此,它是治疗血氨中毒、肝昏迷的有效约物。它对治疗一般的肝病、清除疲劳、提高智力及男性不育,也有一定的疗效。过去,我国精氨酸的生产仅有少数厂以明胶作原料,进行小规模的生产。伟大的无产阶级文化大革命,推动了科研和生产的发展。目前除了用明胶作原料生产精氨酸外,尚有利用水解猪毛提取胱氨酸后的废液生产精氨酸,使精氨酸除了供应国内医药部门的需要外,开始     

L-酪氨酸合成L-多巴的研究

<正> L-酪氨酸是许多农副产品的蛋白质的组成之一,在利用某些农副产品作原料生产所需产品时,往往有大量酪氨酸从废液、废渣中被丢弃,例如:用毛发制备胱氨酸,国内已年产胱氨酸几百吨,而毛发中含2—3％的酪氨酸,大都从废液中排掉,茧丝工业的废水中和蚕蛹中都含有不少酪氨酸。L-多     

利用味精生产废液生产饲料酵母

我们以味精生产过程中离子交换工序排出的废液作原料,直接用碱调pH3.5—4后,接入热带假丝酵母(Candida tropicalis),于30—32℃摇瓶培养16小时,可得干菌体8克/升。用50升发酵罐培养时,以半连续法进行酵     

玉米秸秆和异Vc钠生产废液固态发酵生产高蛋白饲料研究

以玉米秸秆为原料,以麸皮和异Vc钠生产废液(WEP)为辅料进行生物蛋白饲料固态发酵研究.通过菌种配伍试验,确定了混菌发酵菌种为白地霉、产朊假丝酵母和枯草芽孢杆菌.在此基础上通过单因素优化试验确定了秸秆蛋白饲料的最优发酵条件:以玉米秸秆(5 g)和麸皮(1 g)为基料,4%WEP营养液,固液比1:4(g/mL),初始pH值4.5;以麸皮浸汁作种子培养液,种龄24 h,各菌接种比例为产朊假丝酵母∶白地霉∶枯草芽孢杆菌=3:1:1,接种量2 mL;28℃、静置发酵2 d,在此条件下,秸秆饲料中真蛋白含量为6.21%,比对照提高了23.95%.该研究为秸秆和异Vc钠生产废液的高质化利用提供了新的思路和途径.     

酒精废液用于单细胞蛋白的生产

本文采用蔗糖蜜生产酒精后得到的蒸馏废液来培养Candida和Paecilomyes菌株,生产单细胞蛋白。报导了用两种菌株进行的小型和大型的试验结果以及细胞材料中有关的化学成分,氨基酸、维生素含量和生理价值的数据。在产糖国家中所得到的酒精废液的数量是相当大的。每立方米酒精废液可生产干酵母约15公斤。 培养基的制备:在1升酒精废液中加入2—3.5克硫酸铵和0.2—0.3克磷酸氢铵。每升加入20克琼脂来制备斜面培养基。调P~H4.5—5。培养温度为30℃。     

使用硅藻土处理发酵废液、提高丁醇发酵废液回用率

以生物柴油为萃取剂耦联丁醇发酵,能以最为节能的方式生产"改良型"生物柴油、提高发酵性能,但却也产生了大量发酵废液、萃余液回用率超过50%次轮发酵就无法正常进行.探讨了使用硅藻土处理发酵废液、提高废液回用率的可能性和最适条件,在使用40目硅藻土、用量3%(w/v)的条件下,废液回用率可以提高至75%;对提高废液回用率的原因进行了初探,利用少量硅藻土可以吸附发酵残液中的丁醇,减少因美拉德反应所生成的不同分子量的增殖抑制型色素物质.原位添加微量硅藻土有利于丁醇发酵的进行,在使用油醇的萃取发酵条件下,丁醇总生产强度提高了8%.     

谷氨酸脱盐废液培养普通小球藻(Chlorella vugaris)C9-JN2010

研究小球藻在谷氨酸脱盐废液中生长,藻细胞组分及废液中营养利用的效果。结果表明:停留时间10 d,小球藻在体积分数为2%脱盐废液中生长最佳,对总糖、总氮及总磷的消耗率分别为99.1%、96.0%和97.0%;细胞干质量、比生长速率和最大生产强度分别为5.60 g/L、0.223 d-1和560.0 mg/(L.d),细胞中粗蛋白质、粗脂肪、粗纤维、粗灰分及总磷含量(以质量百分数计)分别为50.0%±5.0%、10.0%±2.0%、4.0%±0.5%、6.0%±0.5%和0.80%±0.10%。     

冻胶法提取杜仲胶的研究

采用物理方法暴露杜仲胶丝,用混合溶剂ML提取,滤液冷却后形成冻胶并与溶剂分离,成为提取杜仲胶的一种独特方法。本法无废液污染,提取效率高,操作简单。     

猪毛中胱氨酸的分离和复合氨基酸的制备

本文研究了以猪毛为原料,经过水解、赶酸、中和、结晶、精制提取出胱氨酸纯品;并从分离胱氨酸后的母液中,经过脱色、离子交换、浓缩、结晶、精制,制备出复合氨基酸.在本工艺条件下,胱氨酸产品的收率为4.8%,纯度在99%以上;复合氨基酸产品的收率为41%,纯度在83%以上.本文为扩大试验打下了基础.     

Flexible biorefinery for producing fermentation sugars, lignin and pulp from corn stover

A new biorefining process is presented that embodies green processing and sustainable development. In the spirit of a true biorefinery, the objective is to convert agricultural residues and other biomass feedstocks into value-added products such as fuel ethanol, dissolving pulp, and lignin for resin production. The continuous biomass fractionation process yields a liquid stream rich in hemicellulosic sugars, a lignin-rich liquid stream, and a solid cellulose stream. This paper generally discusses potential applications of the three streams and specifically provides results on the evaluation of the cellulose stream from corn stover as a source of fermentation sugars and specialty pulp. Enzymatic hydrolysis of this relatively pure cellulose stream requires significantly lower enzyme loadings because of minimal enzyme deactivation from nonspecific binding to lignin. A correlation was shown to exist between lignin removal efficiency and enzymatic digestibility. The cellulose produced was also demonstrated to be a suitable replacement for hardwood pulp, especially in the top ply of a linerboard. Also, the relatively pure nature of the cellulose renders it suitable as raw material for making dissolving pulp. This pulping approach has significantly smaller environmental footprint compared to the industry-standard kraft process because no sulfur- or chlorine-containing compounds are used. Although this option needs some minimal post-processing, it produces a higher value commodity than ethanol and, unlike ethanol, does not need extensive processing such as hydrolysis or fermentation. Potential use of low-molecular weight lignin as a raw material for wood adhesive production is discussed as well as its use as cement and feed binder. As a baseline application the hemicellulosic sugars captured in the hydrolyzate liquor can be used to produce ethanol, but potential utilization of xylose for xylitol fermentation is also feasible. Markets and values of these applications are juxtaposed with market penetration and saturation.     

Consumption of water-insoluble phenolic products of lignin pyrolysis by the strain Penicillium tardum H-2

Abstract-Physiological and biochemical properties of the strain Penicillium tardum H-2, a degrader of phenolic compounds formed during lignin pyrolysis, have been characterized. The micromycete P. tardum H-2 can consume phenol, pyrocatechol, p-cresol, vanillin, and guaiacum resin. When grown in a medium containing the water-soluble fraction of lignin pyrolysis waste at concentrations from 0.5 to 2%, it consumes 62-72% of the phenolic components of the waste. According to gas-liquid chromatography, cultivation of P. tardum H-2 in a medium with liquid pyrolysis products results in a complete consumption of the phenol-cresol fraction.     

Biodegradation and Decolorization of Pulp and Paper Mill Effluent by Anaerobic and Aerobic Microorganisms in a Sequential Bioreactor

Summary Paecilomyces sp. and Pseudomonas syringae pv myricae (CSA105) were isolated from sediment core of drainage of the pulp and paper mill industry. Fungi and bacteria were applied for treatment of pulp and paper mill effluent in a two-step and three-step fixed film sequential bioreactor containing sand and gravel at the bottom of the reactor for immobilization of microbial cells. Degradation of chlorinated phenols and formation of their metabolites were determined by high performance liquid chromatography. The microbes exhibited significant reduction in colour (88.5%), lignin (79.5%), chemical oxygen demand (87.2%) and phenol (87.7%) in two-step aerobic sequential bioreactor, and colour (87.7%), lignin (76.5%), chemical oxygen demand (83.9%) and phenol (87.2%) in three-step anaerobic-aerobic sequential bioreactor.     

Colour removal of anaerobically treated pulp and paper mill effluent by microorganisms in two steps bioreactor

In the present study sequential anaerobic and aerobic treatment in two steps bioreactor was performed for removal of colour in the pulp and paper mill effluent. In anaerobic treatment, colour (70%), lignin (25%), COD (42%), AOX (15%) and phenol (39%) were reduced in 15 days. The anaerobically treated effluent was separately applied in bioreactor in presence of fungal strain, Paecilomyces sp., and bacterial strain, Microbrevis luteum. Data of study indicated reduction in colour (95%), AOX (67%), lignin (86%), COD (88%) and phenol (63%) by Paecilomyces sp. where as M. luteum showed removal in colour (76%), lignin (69%), COD (75%) AOX (82%) and phenol (93%) by day third when 7 days anaerobically treated effluent was further treated by aerobic microorganisms. Change in pH of the effluent, and increase in biomass of microorganisms substantiated results of the study, which was concomitant to the treatment method.     

Effects of directly soluble and fibrous rapidly acidifying chemical oxygen demand and reactor liquid surface tension on granulation and sludge-bed stability in upflow anaerobic sludge-blanket reactors

 In recent years, it has become clear that the rapidly acidifying chemical oxygen demand (RACOD) content of the waste water and the surface tension of the reactor liquid contribute to the phenomenon of granular growth in upflow anaerobic sludge-blanket reactors (UASB). By adding 20% of directly soluble RACOD, in the form of a sucrose/starch mixture, on top of the original COD load and by adjusting the reactor liquid surface tension below 50 mN m⁻¹ with linear alkylbenzenesulphonate, granular growth and sludge-bed stability could be enhanced significantly within 40 days. Carrot pulp, a waste product having a high short-chain fatty acid precursor potential, was applied as an alternative fibrous RACOD source. Best results were obtained when adding the carrot pulp freshly to the laboratory-scale UASB reactor in an in-recycle liquefying chamber. This concept of adding carrot pulp waste product as a granular growth supplement by means of an in-recycle liquefying chamber therefore merits testing in practice. Received: 30 October 1996 / Received version: 3 February 1997 / Accepted: 10 February 1997     

Hydrothermal treatment and ethanol pulping of sunflower stalks

The influence of temperature in the hydrothermal treatment of sunflower stalks on the composition of the liquid fraction obtained was examined. The remaining solid fraction was subjected to ethanol pulping in order to obtain pulp that was used to produce paper sheets. The pulp was characterized in terms of yield, kappa index, viscosity, and cellulose, hemicellulose and lignin contents; and the paper sheets in terms of breaking length, stretch, burst index and tear index. Hydrothermal treatment of the raw material at 190 degrees C provided a liquid phase with maximal hemicellulose-derived oligomers and monosaccharide (glucose, xylose and arabinose) contents (26.9 and 4.2 g/L, respectively). Pulping the solid fraction obtained by hydrothermal treatment at 180 degrees C, with 70% ethanol at a liquid/solid ratio of 8:1 at 170 degrees C for 120 min provided pulp with properties on a par with those of soda pulp from the sunflower stalks, namely: 36.3% yield, 69.1% cellulose, 12.6% hemicellulose, 18.2% lignin and 551 ml/g viscosity. Also, paper sheets obtained from the ethanol pulp were similar in breaking length (3.8 km), stretch (1.23%), burst index (1.15 kN/g) and tear index (2.04 m Nm(2)/g) to those provided by soda pulp.     

Biodegradability of lignin—Polypropylene composite films

Biological degradation of composite lignin-polypropylene films containing 4% organocell lignin was confirmed by treatment with lignin-degrading enzymes produced by the white-rot fungusPhanerochœte chrysosporium. The kinetics ofP. chrysosporium culture in the presence of lignin-containing and lignin-free polypropylene films show that the fungus produced lignin-degrading enzymes into the liquid medium during incubation with the lignin-polypropylene film. The degree of biodegradation of both types of film was followed by monitoring their mechanical properties. Correlation was found between the decrease of elongation at break and the amount of released lignin fragments into the extracellular fluid in the course of microbial treatment. The incorporation of lignin into polyolefins represents a new way of using wastes from pulp and paper industry to reduce the environmental impact factor of waste plastics.     

Differential and synergistic effects of xylanase and laccase mediator system (LMS) in bleaching of soda and waste pulps

AIMS: Investigation of waste pulps and soda pulp bleaching with xylanase (X) and laccase mediator system (LMS) alone and in conjunction (one after the other) (XLMS). METHODS AND RESULTS: Soda and different grades of waste pulp fibres [used for making three-layered duplex sheets - top layer (TL), protective layer (PL) and bottom layer (BL)] when pretreated with either xylanase (40.0 IU g(-1)) or LMS (up to 200.0 U g(-1)) alone and in combination (one after the other) (XLMS) exhibited an increase in release of reducing sugars [up to 881.0% soda pulp; up to 736.6% (TL), up to 215.7% (PL) and up to 198.0% (BL) waste pulp], reduction in kappa number [up to 17.6% soda pulp; up to 14.0% (TL), up to 25.3% (PL) and up to 10.9% (BL), waste pulp], improvement in brightness [up to 20.4% soda pulp; up to 23.6% (TL), up to 8.6% (PL) and up to 5.0% (BL), waste pulp] when compared with the respective controls. The usage of XLMS along with 15% reduced level of hypochlorite at CEHHXLMS/EHHXLMS bleaching stage reduced kappa number [5.5% soda pulp; 11.4% (TL), 7.9% (PL), waste pulp] and improved brightness [1.0% soda pulp; 0.9% (TL), 1.4% (PL) waste pulp] when compared with the controls. Scanning electron microscopic studies revealed development of cracks, flakes, pores and peeling off the fibres in the enzyme-treated pulp samples. These modifications of the fibre surface during enzymatic bleaching in turn indicated the removal of lignin and derived compounds from the fibre cell wall. CONCLUSIONS: The work describes synergistic action of xylanase with LMS for bleaching of waste and nonwood pulps for eco-friendly production of paper and thus reveals a new unexploited arena for enzyme-based pulp bleaching. SIGNIFICANCE AND IMPACT OF THE STUDY: The drastic improvement in pulp properties obtained after xylanase and LMS treatment would improve the competitiveness of enzyme-based, environmentally benign processes over chemicals both economically and environmentally.     

Application of laccase-natural mediator systems to sisal pulp: An effective approach to biobleaching or functionalizing pulp fibres?

The effects of laccase-natural mediator systems (LMS) on sisal pulp and their potential for either biobleaching or functionalizing (via radical-coupling) its fibres were investigated. The enzyme treatment (L stage) was followed by extraction with hydrogen peroxide in order to determine whether observable effects could be enhanced by removing LMS-modified lignin. Four different plant phenols [viz. the p-hydroxycinnamic compounds sinapic acid (SNC), ferulic acid (FRC), coniferyl aldehyde (CLD) and sinapyl aldehyde (SLD)] were used as laccase redox mediators and their effects on pulp and effluents compared with those of the synthetic compound 1-hydroxybenzotriazole (HBT). During the L stage performed with HBT, laccase underwent a loss of 99% and 78% of the initial activity, in the absence and presence of pulp, respectively. With natural mediators inactivation was markedly reduced, being the residual activity between 65% and 100% of the initial one, in the presence of pulp. The pulp was found to protect the enzyme against inactivation: the activity was only reduced by 45% in its presence. Under the operating conditions used the natural mediators proved less efficient than HBT in facilitating pulp bleaching; rather, they tended to bind to pulp fibres. This effect could be used to functionalize fibres in order to improve intrinsic properties of pulp or introducing novel ones (e.g. antimicrobial, antioxidant, optical properties, etc.). This paper shows for the first time the application of laccase-mediator systems to sisal pulp.