生物高分子的纺织应用

随着人们对纺织工业影响环境问题的不断关注,越来越多的纺织学者、生产商及制造商开始寻求生物可降解和可持续发展的生物高分子纤维,并将其作为减少纺织品对环境影响的一种有效方法。生物高分子是一种可以生物降解的聚合物。用于生产这类聚合物的原料可以是天然的,也可以是人工合成的。用于纺织领域的生物高分子主要有4种,分别为淀粉、多糖、纤维素及合成材料。所有的天然纤维都是生物可降解材料。纤维素是地球上最常见的生物高分子和有机化合物。除一些传统的纤维素纤维(如棉纤维)外,还存在很多特殊的生物高分子(如海藻、甲壳素或壳聚糖、淀粉、角蛋白,以及生物合成的纤维素)纤维。     

淀粉基生物可降解材料的研究进展

淀粉基生物可降解材料是一种可再生、可降解的高分子共混物质,它具有来源广、成本低、性能良好的特点,是一种理想的塑料替代品。主要详细阐述了热塑性淀粉(TPS)的性质,以及热塑性淀粉和不同的合成聚合物、天然高分子共混体系的研究现状,分析了淀粉基生物可降解材料目前存在的问题,并对其今后的发展方向进行了展望。     

轻工业科技发展指南──行业研究试制重点

一、发酵行业发酵工业是生物技术应用的重要领域,因此将当代重组DNA、细胞融合、酶工程、发酵工程等生物高新技术应用于发酵工业研究开发发酵新产品,始终是发酵工业的方向。采用电子、新材料、节能、清洁生产等高新技术改造发酵工业,使之生产现代化也是当今科技工作的重点。─—微生物发酵法生产功能型甜味剂和盐味剂的研究（包括糖醇、肽类等）;─—新型微生物聚合物研制和应用研究（包括具有食品和环保应用价值的,具有材料亲和性多糖的研究）;─—具有高活性、低毒性新型微生物乳化剂的研制与开发;─—微生物法生产天然香精、香…     

大肠杆菌代谢工程生产芳香族化合物研究进展

芳香族化合物广泛应用于化工、食品及医药等领域,多来自于化工合成或天然产物提取。天然微生物也具有合成芳香族化合物的能力,以维持自身生命活动代谢需求,但其积累能力较低。近几年利用代谢工程的方法对微生物特别是大肠杆菌进行途径优化、设计、改造等方法在提高其芳香族化合物的发酵产量方面取得了显著成效,并且创新地生产出多种有价值的芳香族衍生物。这些研究成果对于未来以合成生物学和细胞工厂为基础利用可再生资源进行工业生物制造,解决化石能源危机和天然产物提取等问题具有重要意义。     

利用生物传感器测定氨基酸

生物传感器由酶和微生物等的生体触酶和物理化学装置构成。物理化学装置用各种离子选择性电极、半导体元件、热敏电阻、光子计算机等。根据用物理化学装置测定与生体有关的生物化学反应生成或消耗的化学物质、热、光等这一原理。生物传感器采用共有结合法把生物体触媒固定在合成高分子膜上或天然高分子膜上的方法和生物体触媒包括埋在高分子凝胶膜中的方法。     

微生物生产天然虾青素的合成途径及其研究进展

虾青素是一种天然存在的类胡萝卜素，具有重要的生物活性，如着色功能、高抗氧化性、抗癌、抗炎等。动物机体对反式虾青素吸收利用率、着色能力和抗氧化活性更高。微生物生产天然虾青素成为研究热点，一是利用藻类生产，二是利用酵母发酵生产。文章着重阐述了微生物生产天然虾青素的合成途径、红酵母产虾青素的研究进展及其功效与应用，为红酵母发酵生产虾青素提供一定的理论基础和参考。     

可降解塑料的研究进展

添加光敏剂型的光降解塑料以及改性淀粉添加型的生物降解塑料成为各国开发的重点，技术已日趋成熟，进入商品化阶段，并向光－生物聚合降解的方向发展。光降解塑料正进入用结构合成方法来制备光降解聚合物的阶段，以天然高分子、微生物合成高分子、化学合成高分子制备完全生物降解塑料，愈来愈受到重视，从合成技术上展示出生物技术在新材料领域的应用前景。     

静电纺丝法制备聚乙烯醇复合纳米纤维的研究进展

聚乙烯醇(PVA)是一种亲水性聚合物,其因具有良好的化学稳定性、热稳定性、生物相容性、低毒性等优点而被广泛应用于各领域。综述国内外静电纺丝法制备PVA复合纳米纤维的研究现状,重点介绍PVA/碳纳米材料、PVA/金属纳米粒子、PVA/无机氧化物纳米粒子、PVA/天然高分子、PVA/合成高分子等复合纳米纤维的研究进展,以及它们在组织工程支架、过滤材料、纳米传感器、药物传递系统、生物医学工程等领域的应用,分析潜在应用,展望发展前景。     

具有抗菌功能的可降解复合包装材料的制备

合成高分子材料是目前市面上常用的包装材料,如聚乙烯、聚丙烯等.这些合成高分子具有成膜性高、可塑性高等优点,但难以降解,大量使用后易造成"白色污染"等严重的环境问题.制备可降解的包装材料是当前减少环境中"白色污染"的重要方法.以生物可降解的天然高分子玉米淀粉为主要原料,将其与生物相容性的聚乙烯醇进行有效复合,并引入抗菌单...     

ε-聚赖氨酸发酵工艺的研究进展

ε-聚赖氨酸(ε-poly-L-lysine,ε-PL)是由白色链霉菌产生的一种新型天然聚合物,由25～35个L-赖氨酸通过α-羧基和ε-氨基连接形成。现代生物技术基因工程、基因组重排和响应面法已经在工业规模上显著提高了这种新型同源多聚氨基酸的合成效率,并扩展了其工业应用。ε-PL已被广泛用作食品和化妆品行业的防腐剂,生物可降解材料,基因转运载体等。近年来的研究主要集中在微生物技术生产ε-PL和生物合成机理方面。文章着重介绍了ε-PL发酵工艺的研究进展,包括培养基的优化、p H控制策略、溶解氧控制策略、生物反应器和其他生产工艺;概述了ε-PL生物合成和产ε-PL菌株分离改造。这将有助于这种新型聚合氨基酸的发展,同时为其他生物聚合物的研究提供参考。     

Exopolysaccharides produced by Lactobacillus sp.: Biosynthesis and applications

Lactobacillus sp. synthesize exopolysaccharides (EPS), including both homo- and heteropolysaccharides, which play an important role in the production of fermented foods, and especially in the dairy industry, improving the gustatory and rheological properties of the finished products. These polymers are generated by starter cultures in situ in fermented foods, and so they are treated as natural thickening agents. As some Lactobacillus strains are generally recognized as safe and have been shown to exhibit probiotic activity, EPS from those bacteria can be used as functional food ingredients, conferring both health and economic benefits to the consumers. However, their industrial applications are hindered by the low yield of EPS from Lactobacillus and high costs of their purification. This review focuses on the latest reports concerning the biosynthesis and properties of Lactobacillus EPS.     

Chitosan-based biodegradable functional films for food packaging applications

Chitin is the structural material of crustaceans, insects, and fungi, and is the second most abundant biopolymer after cellulose on earth. Chitosan, a deacetylated derivative of chitin, can be obtained by deacetylation of chitin. It is a functionally versatile biopolymer due to the presence of amino groups responsible for the various properties of the polymer. Although it has been used for various industrial applications, the recent one is its use as a biodegradable antimicrobial food packaging material. Much research has been focused on chitosan-based flexible food packaging and edible food coatings to compete with conventional non-biodegradable plastic-based food packaging materials. Various strategies have been used to improve the properties of chitosan - using plasticizers and cross-linkers, embedding the polymer with fillers such as nanoparticles, fibers, and whiskers, and blending the polymer with natural extracts and essential oils and also with other natural and synthetic polymers. However, much research is still needed to bring this biopolymer to industrial levels for the food packaging applications.Industrial relevanceAs a major by-product of the seafood industry, a massive amount of crustacean shell waste is generated each year, which can be used to produce value-added chitin, which can be converted to chitosan using a relatively simple deacetylation process. Being extracted from a bio-waste product using many energy-efficient methods, chitosan is much cheaper as compared to other biopolymers. Nevertheless, the exceptional properties of chitosan make it a relatively stronger candidate for food packaging applications. Chitosan has already been used in various industries, such as biomedical, agriculture, water treatment, cosmetics, textile, photography, chromatography, electronics, paper industry, and food industry. This review article compiles all the essential literature up to the latest developments of chitosan as a potential food packaging material and the outcomes of its practical utilization for this purpose.     

淀粉基生物降解塑料的研究进展

我国淀粉资源丰富、价格低廉，淀粉作为可完全生物降解的天然高分子材料日益受到人们的重视。本文综述了当今淀粉基生物降解塑料的分类、研究方法、发展状况，以及当今淀粉基生物降解塑料发展中存在的一些问题和应用前景。     

两性高分子絮凝剂的制备与应用

两性高分子絮凝剂是一类性能优异的多功能高分子聚合物,在造纸废水处理中得到广泛的应用,具有诱人的开发前景。该文介绍了两性高分子絮凝剂的制备方法及其在造纸废水处理中的应用现状。     

Composites from Bast Fibres-Prospects and Potential in the Changing Market Environment

Abstract

Composite materials reinforced with natural fibres, such as flax, hemp, kenaf and jute, are gaining increasing importance in automotive, aerospace, packaging and other industrial applications due to their lighter weight, competitive specific strength and stiffness, improved energy recovery, carbon dioxide sequestration, ease and flexibility of manufacturing and environmental friendliness besides the benefit of the renewable resources of bast fibres. The market scenario for composite applications is changing due to the introduction of newer biodegradable polymers, such as PLA synthesized from corn, development of composite making techniques and new stringent environmental laws requiring improved recyclability or biodegradability for industrial applications where stress bearing capacities and micro-mechanical failures dictate serviceability. Bast fibre reinforced composites, made from biodegradable polymers, will have to compete with conventional composites in terms of their mechanical behaviour. Biocomposites, in which natural fibres, such as kenaf, jute, flax, hemp, sisal, corn stalk, bagasse or even grass are embedded in a biodegradable matrix, made as bioplastics from soybean, corn and sugar, have openedup new possibilities for applications in automotive and building products. Obviously, new approaches to research and development will be required to improve their mechanical properties, such as tensile, bending and impact resistance to match their performance and commercial competitiveness against petroleum based products. The research community has to look at the various possibilities of combining natural fibres, such as sisal, flax, hemp and jute with polymer matrices from non-renewable and renewable resources to develop cost effective biocomposites. This paper will review the newer products and techniques that can improve the properties of bast fibre based composites as well as potential structural and non-structural applications which can increase their market share.     

端氨基蔗渣纤维素对水中重金属离子微污染吸附的研究进展

在重金属污染日益严重的今天,重金属污染的治理已经越来越受到广泛的关注。纤维素分子含有大量的羟基,但天然纤维素吸附能力并不好,通过化学改性后可成为性能良好的吸附剂。纤维素无污染、易生物降解、且来源广泛价格低廉,对其研究已成为该领域的热点,并已被广泛应用于重金属污染治理领域。超支化聚合物大分子作为一类制备工艺并不繁琐且容易得到树状高分子聚合物,其最大特点就是准球形的分子结构及末端官能团的可控性,其研究愈加受到关注。本文在文献综述的基础上,提出合成一种含有端氨基超支化合物结构的蔗渣改性重金属吸附剂的可行性技术设想。     

Edible and Biodegradable Starch Films: A Review

Mainly due to environmental aims, petroleum-based plastics are being replaced by natural polymers. In the last decades, starch has been evaluated in its film-forming ability for applications in the food packaging area. Characteristics of the starch film matrices, the film formation methods, and physicochemical properties of the starch films are reviewed in this paper. The influences of different components added in casting methods and thermoplastic processes have been also analyzed. Comparison of mechanical properties of newly prepared starch films and stored films reveals that the recrystallization phenomenon made the films more rigid and less stretchable. These effects can be inhibited by adding other polymers to the starch matrix. Other approaches to improve the starch films’ properties are the reinforcement by adding organic or inorganic fillers to the starch matrix as well as the addition of functional compounds. In this way starch films have improved mechanical and barrier properties and can act as a bioactive packaging. Physicochemical properties of the starch films showed a great variability depending on the compounds added to the matrix and the processing method. Nevertheless, dry methods are more recommendable for film manufacturing because of the greater feasibility of the industrial process. In this sense, a better understanding of the nano and microstructural changes occurring in the matrices and their impact on the film properties is required.     

Metabolic engineering pathways for rare sugars biosynthesis,physiological functionalities,and applications—a review

ABSTRACT

Biomolecules like rare sugars and their derivatives are referred to as monosaccharides particularly uncommon in nature. Remarkably, many of them have various known physiological functions and biotechnological applications in cosmetics, nutrition, and pharmaceutical industries. Also, they can be exploited as starting materials for synthesizing fascinating natural bioproducts with significant biological activities. Regrettably, most of the rare sugars are quite expensive, and their synthetic chemical routes are both limited and economically unfeasible due to expensive raw materials. On the other hand, their production by enzymatic means often suffers from low space-time yields and high catalyst costs due to hasty enzyme denaturation/degradation. In this context, biosynthesis of rare sugars with industrial importance is receiving renowned scientific attention, across the globe. Moreover, the utilization of renewable resources as energy sources via microbial fermentation or microbial metabolic engineering has appeared a new tool. This article presents a comprehensive review of physiological functions and biotechnological applications of rare ketohexoses and aldohexoses, including D-psicose, D-tagatose, L-tagatose, D-sorbose, L-fructose, D-allose, L-glucose, D-gulose, L-talose, L-galactose, and L-fucose. Novel in-vivo recombination pathways based on aldolase and phosphatase for the biosynthesis of rare sugars, particularly D-psicose and D-sorbose using robust microbial strains are also deliberated.     

天然高分子水处理剂在染料废水处理中的应用

用于水处理的天然高分子及其衍生物主要有纤维素、淀粉、木质素、壳聚糖，本文简要概述了四类天然高分子水处理剂在染料废水处理中的应用研究现状。     

Microbial Starch‐Converting Enzymes: Recent Insights and Perspectives

Starch is an abundant, natural, renewable resource, and present as the major storage carbohydrate in the seeds, roots, or tubers of many important food crops, such as maize, wheat, rice, potato, and cassava. Uses of native starches in most industrial applications are limited by their inherent properties. Hence, they are often structurally modified after isolation to enhance desirable attributes, to minimize undesirable attributes, or to create new attributes. Enzymatic, rather than chemical, approaches are used in the production of starch syrups, maltodextrins, and cyclodextrins. However, the desire for starch‐active enzymes working optimally at high temperatures and low pH conditions with superior stability and activity is still not satisfied and this stimulates interest in developing novel and improved starch‐active enzymes through a variety of strategies. This review provides current information on enzymes belonging to GH13, 57, 70, and 77 that can be used in structural modifications of the starch polysaccharides or to produce starch‐derived products from them. The characteristics and catalytic mechanisms of microbial enzymes are discussed (including 4‐α‐glucanotransferase, branching enzyme, maltogenic amylase, cyclomaltodextrinase, amylosucrase, and glucansucrase). Product diversity after starch‐converting reaction and utilization in industrial applications are also dealt with.