Plant-derived materials

Production of Metal Nanoparticles by Plants and Plant-Derived Materials... 

Currently, nanotechnology research is propelled by the need to develop strategies for the synthesis of nanoparticles with controlled shape and size distributions. The aim of this chapter is to provide some insight into the recent advances in nanoparticle synthesis using plants and plant derived materials. 

At the end of the century there was general acceptance that HS are complex compounds of a synthetic nature formed as the result of decomposition involving two or more plant-derived materials. For example, Deherain (1902) considered that HS synthesis involves interactions between proteins and encrusting substances, mainly lignin. This concept was later developed as the ligno-protein complex of Waksman and Iyer (1932,1933) (see Section 1.4.5) and as described by Waksman (1936). 

Despite the general move towards use of fossil hydrocarbon feedstocks, some plant-derived materials have continued to provide economic or technical benefits that ensure they remain the preferred source of raw materials for industry. For example, cotton still accounts for 38% of all textile production due to its airflow- and temperature-regulating capabilities, which are difficult or costly to replicate with man-made fibres. Linseed oil remains a key feedstock in surface coating and linoleum flooring applications. Plant oils are still widely used in the oleochemicals sector, where coconut and palm oils are widely used in detergent... 

There are a number of economic, environmental and other factors affecting consumer purchasing and industry response to such pressures, and other legislative developments that are prompting reassessment of the opportunities and properties that plant-derived materials can offer. Pressures include ... 

Clearly such approaches are only suited to high-value outlets, but there are still other developing opportunities to access lower-value bulk-market applications for plant-derived materials. 

The petrochemical industry typically works on a build-up approach where the base oil feedstock is fractionated, and complex materials are built up from simpler ones, producing a wide array of materials in the process, for a range of market outlets. The future exploitation of plant materials is seen in a somewhat similar fashion, although in contrast to the petrochemical industry, there will typically be an initial breaking up of more complex materials into simpler building blocks that can then be utilised and built on with the support of chemical, biochemical and catalytic processes, to produce more complex products synonymous with those produced by today s petrochemical industry. This whole crop approach to industrial use of plant-derived material is typically termed biorefining (see Chapter 1). 

Tannic acid has been reported to inhibit the formation of hydroxyl radical by chelation of Fe2+ [16], Because tannic acid is a plant-derived material, it and other natural polyphenols may be important for subsurface applications of Fenton chemistry. A study of 50 different iron chelators assessed the affect of each chelator on the Fenton process initiated with Fe3+ and hydrogen peroxide [17]. Among the nine classes of chelators tested, results indicated that the chelators ranged from inactive to highly active in terms of hydroxyl radical formation. 

It is possible to generate vanillin from other plant-derived materials by biotransformation. 

Lignocellulosic biomass refers to plant-derived material such as bagasse, com stover, wheat straw, rice straw, wood chips and switch grass. It is an abundant and renewable resource which is also potentially carbon-neutral and potentially economically viable if appropriate processing methods can be developed to extract and... 

Hemicellulases endo- and exoxylanases, pentosanases, mannases, arabinases, galactanases Bread and biscuit making, brewing, processing of plant derived materials, starch and gluten processing, coffee manufacturing, animal feed... 

Using the advanced bioethanol technology available, it is possible to produce ethanol from any cellulose/hemicellulose material, which means any plant or plant-derived material. Many of these materials are not just underutilized and inexpensive, but also create disposal problems. For example, rice straw and wheat straw are often burned in the field, a practice that is becoming limited by air pollution concerns. Also, much of the material now going into landfills is cellulose/hemicellulose material and could be used... 

The content of aromatic carbon varies considerably in marine and estuarine humic acids, but is, in all cases, greater than that of Mangrove Lake humic acids. This is probably a reflection of the greater contribution of vascular plant-derived material which can be expected to provide lignin-like components rich in aromatic structures. Note that the humic acids from fluvial sediments of the Potomac River are the most aromatic. Peaks at 150 and 55 ppm are characteristic of oxygen-substituted aromatic carbons typically associated with lignin of vascular plants. Humic acids from New York... 

Due to the relative ease of access to plants, plant-derived materials have been in the majority as far as sources are concerned, with microbial sources being especially important in the antibiotic area. Recent work suggests that marine organisms will play an increasingly important role in the future, especially with the increasing power of organic synthesis to address the supply problems inherent with this source material. In the future, with the advent of genetic techniques that permit the isolation and expression of biosynthetic cassettes, microbes and their marine invertebrate hosts may well be the new frontier for natural products. 

Over the last 30 years, the paint industry has become almost completely dependent on materials manufactured from hydrocarbons. Paints made from plant-derived materials such as linseed oil are still produced but latex, epoxy, and urethane-based coatings are made from hydrocarbons. Most of the solvents used in formulating both (plant-derived) oil based and, synthetic paints are extracted or synthesized from hydrocarbons. In many cases the plant derived product, still in use, is reacted with hydrocarbon derived chemicals to improve the film strength, cut the drying time or alter the plant material in some other desirable manner. 

Herbal medicines, plant-derived materials, or products with therapeutic or other human health benefits that contain either raw or processed ingredients from one or more plants (1) have been utilized to treat various diseases for thousands of years, especially in Far Eastern countries. It is estimated that traditional herbal preparations account for 30%-50% of the total medicinal consumption in China (2). However, The quantity and quality of the safety and efficacy data on traditional medicine are far from sufficient to meet the criteria needed to support its use worldwide. The reasons for the lack of research data are due not only to health-care policies, but also to a lack of adequate or... 

Ethanol is being hailed as the fuel of the future. Interest in the production of fuel ethanol from renewable sources has increased significantly. For fuel ethanol production to become a practical reality, cheaper substrates and more efficient production processes are needed [1,2]. Biomass, which includes all plant and plant-derived material, forms a potential renewable source of sugars that can be fermented to produce fuel ethanol and a variety of other fuels and chemicals. In addition to the many benefits common to renewable energy, biomass is particularly attractive because it is currently the only renewable sustainable energy source for liquid transportation fuel. 

Due to ease of access, plant-derived materials have been in the majority as far as sources are concerned. Now, with the advent of genetic techniques that permit the isolation and expression of biosynthetic cassettes, microbes and their marine invertebrate hosts may well be the new frontier for natural products. 

The khapra beetle, T. granarlum, inhabits an environment more similar to that of the confused flour beetle than to the usual environment of other members of the family Dermestidae to which the khapra beetle belongs. However, with respect to utilization of dietary sterols, the khapra beetle Is more similar to other dermestids such as the hide beetle, Dermestes maculatus, (31) which usually feeds on animals or animal products rather than plant derived material. Apparently, the khapra beetle has not had to alter Its sterol metabolism to adapt to living In Its stored product environment. It will be of Interest to examine the ecdysterolds of the khapra beetle to see If the synthesis of molting hormones In this species has been modified to utilize other than a C27 sterol as an ecdysterold precursor. 

The first major vitamin to be recognised in terms of its influence was vitamin C. This emerged as it was realised that scurvy, a disease of sailors in the days of journeys of many months in sailing ships, was the result of a severely restricted diet, and that it could be relieved or prevented with plant-derived material. Jacques Cartier gave his men a decoction of pine needles James Cook took the simpler option of taking citrus fruit on board and to this day Americans refer to British servicemen as limeys . It was another 150 years before the actual substance responsible for these remarkable effects was isolated from another rich source, green peppers, and identified. Indeed the word vitamin was only introduced in 1912. 

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