植物油新材料研究与开发

植物油高分子材料是生物材料领域一个新兴研究方向.以植物油为原料可以合成聚烯烃、聚醚、聚酯以及聚氨酯等系列高分子化合物.本文总结了利用植物油合成高分子材料的各种化学反应路径,并对植物油新材料清洁生产工艺发展趋势进行了分析.     

聚羟基脂肪酸酯 (PHA) 及其共混纤维研究进展

聚羟基脂肪酸酯(PHA)是代表性的生物基可降解高分子,其种类超过150种,性能多样、可调。文中综述了PHA的研究概况及潜在应用,介绍了四代商业化PHA的性质及其与其他生物基可降解材料形成共混纤维的研究进展。     

生物基聚酰胺研究进展

介绍了各类生物基高分子材料,着重综述了生物基聚酰胺的主要合成路线以及开发应用现状,并就生物基聚酰胺的发展给出了相关建议。     

稀土化合物在农用塑料等高分子材料开发中的应用

综述了稀土化合物在高分子材料科学领域应用研究的现状和进展。     

基于愈创木酚的生物基固化剂对环氧树脂的固化性质

将生物基化合物丁二酸酐和具有芳环刚性结构的愈创木酚通过傅克反应制备得到同时具有酚羟基和羧酸基团的化合物3-(4-羟基-3-甲氧基苯甲酰)丙酸(GSA)。结果发现:GSA可以作为环氧树脂的固化剂,与常用的石油基固化剂4,4-二氨基二苯砜(DDS)相比,GSA的固化体系具有更高的固化反应速率常数。在相同的固化条件下,用GSA固化得到的双酚A型环氧树脂的玻璃化转变温度比DDS固化得到的高了40℃,5%热失重温度提高了107.8℃,显示出了更为优异的热稳定性。本研究对构筑高性能生物基高分子材料提供了借鉴思路。     

生物医用高分子材料在药物控释系统中的应用

药物控制释放体系是继传统载药体系发展起来的一种新型的疾病治疗体系。生物医用高分子材料作为药物控释载体的研究逐渐成为热点之一。近年来,随着研究的深入,生物医用高分子材料在药物控释系统中的运用得到了广泛的发展。本文简要介绍了常用天然医用高分子材料如胶原、纤维素以及环糊精和合成医用高分子材料如聚乳酸、聚酸酐等在药物控释系统中的应用,并对这类材料的应用进行了展望。     

Fe3O4/ 生物可降解复合材料研究

磁性氧化铁纳米粒子因具有尺寸小、低毒性和超顺磁性等特点,已经引起了生物化工、医药工业领域的广泛关注。生物可降解高分子材料是生物医用高分子研究中最活跃的领域之一,已广泛用于外科手术缝合线,植入体材料及药物释放载体等。将Fe3O4和生物可降解高分子材料进行复合,可以扩大两者的应用范围,达到理想的治疗效果,并有望开创临床治疗的新时代。本文介绍了磁性四氧化三铁粒子的化学制备方法,包括共沉淀法、溶胶-凝胶法、微乳液法,并对各种方法的优缺点进行了比较;重点阐述了磁性壳聚糖,磁性聚乳酸,磁性PEG,磁性PCL复合材料的制备,及它们在酶的固定化、磁靶向药物及基因载体等医学领域的应用,显示了Fe3O4/生物可降解复合材料在医学领域的广阔应用前景;最后对复合材料走向临床应用所面临的问题及发展前景进行了讨论。     

Ru基催化剂选择性催化氧化5-羟甲基糠醛制备2,5-呋喃二甲酸研究进展

2,5-呋喃二甲酸(FDCA)是一种重要的生物质基单体,有望替代对苯二甲酸(PTA)生产可降解的生物质聚酯材料,缓解对化石资源的依赖以及环境的污染。如何经济、高效、绿色地合成FDCA是目前迫切需要解决的难题。5-羟甲基糠醛(HMF)作为典型的生物质平台化合物,来源广泛且绿色可持续,以其为原料催化氧化制备FDCA近年来备受关注。负载型Ru基催化剂由于其催化活性高、选择性好、成本相对合理,被认为是HMF催化氧化制备FDCA良好的催化材料。本文基于HMF不同氧化路线及反应机制,首先概述了不同活性组分Ru基催化剂的发展历程及其在HMF氧化反应中的应用,接着详细分析了碱添加剂、溶剂及载体对反应的影响,并阐释了相应的催化机制,最后对Ru基催化剂在HMF催化氧化制备FDCA中的工业化应用进行了总结和展望。     

木质纤维素水热解聚制备能源化工平台化合物

木质纤维素是制备生物液体燃料和化工品的理想原料。介绍了近年来木质纤维素通过水热解聚途径制备能源化工平台化合物和平台化合物碳链增长途径的研究进展,重点讨论了制备5-羟甲基糠醛(HMF)平台化合物的途径、介质、催化剂,分析了水热解聚技术的优势及困难,并对该领域的研究进行了展望。     

仿生黏弹性高分子水凝胶及其生物医学应用

天然细胞外基质和生物体软组织固有的黏弹性是调控细胞行为和组织修复与再生过程的关键因素.基于动态建构化学反应交联得到的动态高分子水凝胶材料可有效模拟在体细胞或组织的黏弹性力学微环境,为体外调控细胞命运、揭示其力学生物学响应机制提供了重要工具,也为组织修复与再生提供了仿生支架材料.本综述在介绍天然细胞外基质及生物体软组织黏弹性的基础上,重点对仿生黏弹性水凝胶材料的设计思路、性能表征及影响因素等进行了概括和总结,并揭示了黏弹性水凝胶调控细胞、组织行为的规律及机制,最后,分析了目前该领域研究中所存在的问题并对未来发展方向进行了展望.本综述将有助于启发高分子水凝胶的仿生功能化设计思路及材料生物学效应研究,进一步拓展高分子水凝胶材料的生物医学应用.     

Binding of Volatile Organic Compounds to Food Biopolymers

Capillary gas chromatography was used to study the influence of the composition and structure of different food polymers (polysaccharides, vegetable fibers, and animal protein gelatin) on the binding of essential oil components. The retention of volatile organic compounds on biopolymers was shown to depend on their molecule structure and the presence, type, and position of a functional group. The maximum extent of the binding was observed for nonpolar terpene and sesquiterpene hydrocarbons, and the minimum extent was observed for alcohols. The components of essential oils were adsorbed due mostly to hydrophobic interactions. It was shown that the composition and structure of a compound, its physico-chemical state, and the presence of functional groups influence the binding. Gum arabic and guar gum were found to bind nonpolar compounds to a maximum and minimum extent, respectively. It was demonstrated the minimum adsorption ability of locust bean gum with respect to all studied compounds.     

Composition and Oil-Water Interfacial Tension Studies in Different Vegetable Oils

The interfacial tension is one of the most important fundamental properties and presents crucial impacts throughout vegetable oil production, application and digestion. In this study, composition of vegetable oil including tocopherols, phytosterols, phenolic compounds, phospholipids, fatty acid composition and other constituents were determined. Furthermore, interfacial tension and its relationship with vegetable oil compositions were analyzed. Distribution and profile of composition of vegetable oil were remarkably different. The interfacial tension results showed physical refined vegetable oil exhibited an obviously lower interfacial tension than chemical refined oil attributed to abundant minor compositions. Moreover, the correlation analysis results indicated that phenolic compounds demonstrated the greatest influence on interfacial tension of vegetable oil against water with r = − 0.671, p = 0.009, followed by free fatty acid value, linoleic acid of triglyceride and phospholipids with r = − 0.639, 0.626, − 0.576 and p = 0.014, 0.017 and 0.031, respectively. No significant correlation was found between interfacial tension and other minor compositions. These results contribute to regulating lipid metabolism and evaluating oil quality more scientifically.

     

Bio-based production of C2-C6 platform chemicals

Platform chemicals composed of 2–6 carbons derived from fossil resources are used as important precursors for making a variety of chemicals and materials, including solvents, fuels, polymers, pharmaceuticals, perfumes, and foods. Due to concerns regarding our environment and the limited nature of fossil resources, however, increasing interest has focused on the development of sustainable technologies for producing these platform chemicals from renewable resources. The techniques and strategies for developing microbial strains for chemicals production have advanced rapidly, and it is becoming feasible to develop microbes for producing additional types of chemicals, including non‐natural molecules. In this study, we review the current status of the bio‐based production of major C2–C6 platform chemicals, focusing on the microbial production of platform chemicals that have been used for the production of chemical intermediates, building block compounds, and polymers. Biotechnol. Bioeng. 2012; 109: 2437–2459. © 2012 Wiley Periodicals, Inc.     

我国6种主要木本油料作物的研究进展

选择我国3种传统木本油料作物油茶(Camellia oleifera)、核桃(Juglans regia)和文冠果(Xanthoceras sorbifolium)以及3种新兴木本油料作物油用牡丹(Paeonia suffruticosa)、星油藤(Plukenetia volubilis)和元宝枫(Acer truncatum), 从种质资源概况、脂肪酸组成、活性成分以及油脂合成代谢的分子生物学等方面进行了详细综述。文章旨在引导国内生产者因地制宜地种植木本油料作物, 从而发挥木本植物油的优势, 补充草本油料供给不足。同时, 在资源保护的前提下, 增加我国植物油供给量, 丰富人们的营养来源和提高健康水平。该文还分析了我国木本油料作物利用中存在的问题, 为进一步开发利用木本油料作物指明了研究方向。     

Natural gums of plant origin as edible coatings for food industry applications

Natural plant-based gums and their derivatives are widely utilized in food industries, however, their applications as edible coatings to extend fresh fruits and vegetable shelf-life has been explored recently. These natural polymeric polysaccharides have many advantages as compared to synthetic polymers, because they are biodegradable, nontoxic, economical and easily available in the environment. Natural gums can also be semi synthetically modified to produce derivatives, which can easily compete with the synthetic preservatives available on the food market. In this review, the recent developments in the use of natural gums and their derivatives as edible coatings have been explored and discussed.     

A review of characterization of tocotrienols from plant oils and foods

Tocotrienols, members of the vitamin E family, are natural compounds found in a number of vegetable oils, wheat germ, barley and certain types of nuts and grains. Vegetable oils provide the best sources of these vitamin E forms, particularly palm oil and rice bran oil contain higher amounts of tocotrienols. Other sources of tocotrienols include grape fruit seed oil, oats, hazelnuts, maize, olive oil, buckthorn berry, rye, flax seed oil, poppy seed oil and sunflower oil. Tocotrienols are of four types, viz. alpha (α), beta (β), gamma (γ) and delta (δ). Unlike tocopherols, tocotrienols are unsaturated and possess an isoprenoid side chain. A number of researchers have developed methods for the extraction, analysis, identification and quantification of different types of vitamin E compounds. This article constitutes an in-depth review of the chemistry and extraction of the unsaturated vitamin E derivatives, tocotrienols, from various sources using different methods. This review article lists the different techniques that are used in the characterization and purification of tocotrienols such as soxhlet and solid–liquid extractions, saponification method, chromatography (thin layer, column chromatography, gas chromatography, supercritical fluid, high performance), capillary electrochromatography and mass spectrometry. Some of the methods described were able to identify one form or type while others could analyse all the analogues of tocotrienol molecules. Hence, this article will be helpful in understanding the various methods used in the characterization of this lesser known vitamin E variant.     

Biodiesel production from Jatropha oil by catalytic and non-catalytic approaches: an overview

Biodiesel (fatty acids alkyl esters) is a promising alternative fuel to replace petroleum-based diesel that is obtained from renewable sources such as vegetable oil, animal fat and waste cooking oil. Vegetable oils are more suitable source for biodiesel production compared to animal fats and waste cooking since they are renewable in nature. However, there is a concern that biodiesel production from vegetable oil would disturb the food market. Oil from Jatropha curcas is an acceptable choice for biodiesel production because it is non-edible and can be easily grown in a harsh environment. Moreover, alkyl esters of jatropha oil meet the standard of biodiesel in many countries. Thus, the present paper provides a review on the transesterification methods for biodiesel production using jatropha oil as feedstock.     

Conversion of acid oil by-produced in vegetable oil refining to biodiesel fuel by immobilized Candida antarctica lipase

Acid oil, which is a by-product in vegetable oil refining, mainly contains free fatty acids (FFAs) and acylglycerols, and is a candidate of materials for production of biodiesel fuel. A mixture (acid oil model) of refined FFAs and vegetable oil was recently reported to be converted to fatty acid methyl esters (FAMEs) at >98% conversion by a two-step reaction system comprising methyl esterification of FFAs and methanolysis of acylglycerols using immobilized Candida antarctica lipase. The two-step system was thus applied to conversion of acid oil by-produced in vegetable oil refining to biodiesel fuel. Under similar conditions that were determined by using acid oil model, however, the lipase was unstable and was not durable for repeated use. The inactivation of the lipase was successfully avoided by addition of excess amounts of methanol (MeOH) in the first-step reaction, and by addition of vegetable oil and glycerol in the second-step reaction. Hence, the first-step reaction was conducted by shaking a mixture of 66 wt% acid oil (77.9 wt% FFAs, 10.8 wt% acylglycerols) and 34 wt% MeOH with 1 wt% immobilized lipase, to convert FFAs to their methyl esters. The second-step reaction was performed by shaking a mixture of 52.3 wt% dehydrated first-step product (79.7 wt% FAMEs, 9.7 wt% acylglycerols), 42.2 wt% rapeseed oil, and 5.5 wt% MeOH using 6 wt% immobilized lipase in the presence of additional 10 wt% glycerol, to convert acylglycerols to FAMEs. The resulting product was composed of 91.1 wt% FAMEs, 0.6 wt% FFAs, 0.8 wt% triacylglycerols, 2.3 wt% diacylglycerols, and 5.2 wt% other compounds. Even though each step of reaction was repeated every 24 h by transferring the immobilized lipase to the fresh substrate mixture, the composition was maintained for >100 cycles.     

Technological trends and market perspectives for production of microbial oils rich in omega-3

In recent years, foods that contain omega-3 lipids have emerged as important promoters of human health. These lipids are essential for the functional development of the brain and retina, and reduction of the risk of cardiovascular and Alzheimer's diseases. The global market for omega-3 production, particularly docosahexaenoic acid (DHA), saw a large expansion in the last decade due to the increasing use of this lipid as an important component of infant food formulae and supplements. The production of omega-3 lipids from fish and vegetable oil sources has some drawbacks, such as complex purification procedures, unwanted contamination by marine pollutants, reduction or even extinction of several species of fish, and aspects related to sustainability. A promising alternative system for the production of omega-3 lipids is from microbial metabolism of yeast, fungi, or microalgae. The aim of this review is to discuss the various omega-3 sources in the context of the global demand and market potential for these bioactive compounds. To summarize, it is clear that fish and vegetable oil sources will not be sufficient to meet the future needs of the world population. The biotechnological production of single-cell oil comes as a sustainable alternative capable of supplementing the global demand for omega-3, causing less environmental impact.