Thursday, October 6, 2011

New partnership looks to industrialize spider silk production

For thousands of years, human beings have looked with envy upon the silk webs spun by spiders; not only are they stronger than steel but they are tougher too (a vest made of spider web material can stop bullets better than Kevlar) and can be stretched farther than rubber before breaking. It’s only in recent years however, that anyone has been able to recreate the webs made naturally by spiders, and now, the company that did it, AMSilk, is teaming up with the Fraunhofer Institute for Applied Polymer Research to figure out a way to mass produce the stuff.

The problem with trying to mass produce spider web material up to now was in building and maintaining spider farms that could produce in sufficient quantities to make it cost effective. AMSilk took another approach, in that they embarked on a mission to figure out how to create spider without having to use actual spiders.

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AMSilk has developed a unique process for producing biopolymers such as spider silk on an industrial scale.

To do that, they began studying the genes of , which is essentially a protein, and then sought out a means for manipulating a harmless variant of the E. Coli bacteria to reproduce it for them in what is known as a bio-reactor (a similar process has been used for years to make other proteins such as insulin).

And that’s exactly what they did; they embedded the spider silk gene into the bacteria causing it to produce the spider silk protein; as the bacterium multiplies so too does the spider silk protein. Thus to produce their silk product all they have to do is cultivate a bunch of the bacteria and then feed it a solution of sugar, salt and a few other micronutrients, then reap the rewards of their efforts. Though this method, they’ve been able to produce products for clients on a semi-custom basis rather than as a means of mass production.

To get around this problem AMSilk is teaming up with Fraunhofer's (who have expertise in creating spin processes for development of biopolymers) hoping that together they can figure out a way to produce their home-grown material in quantities large enough to compete with other synthetic products, such as Kevlar.

The partnership is expected to run two years, by which time, both companies expect to be mass producing spider silk for applications ranging from medical implant coatings, to spring-back type automobile parts.

More information: Press release

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Study finds more effective way to dry ethanol, reduce costs

 Purdue University researchers have found an alternative environmentally friendly and energy-efficient way to dry corn ethanol, and their proof is in the pudding.

Michael Ladisch, a distinguished professor of agricultural and ; Youngmi Kim, a Purdue research scientist; and Ahmad Hilaly, director of process research at Archer Daniels Midland, found that the shape and structure of tapioca pearls are ideal for removing from ethanol. Their findings were reported in the July issue of the journal Industrial & Engineering Chemistry Research.

After fermentation, ethanol contains between 6 percent and 12 percent water, which must be removed to make it fuel-grade. Many ethanol plants use corn grits, which absorb water, or molecular sieves, silica-based particles with tiny pores that only retain water molecules. Ladisch and Kim found that tapioca pearls work better than the conventional corn grit adsorbents.

"Any starch will absorb water. That's how you cook rice or pasta," Kim said. "The tapioca pearl is made of aggregated cassava starch granules that can adsorb more water."

Ladisch said tests found tapioca collected about 34 percent more water than corn. Molecular sieves, while effective, eventually wear out and create waste that must be disposed of. The tapioca can be dried and reused, and when they wear out, they can be used to make more ethanol.

"Tapioca is very efficient, and it's all-natural," Ladisch said. "There are no disposal issues. It's much more environmentally friendly."

Tapioca pearls, essentially spherical, are structured differently than corn grits, Ladisch said. While corn grits are solid, irregularly shaped particles, tapioca pearls contain a gelatin starch core upon which dry starch granules are aggregated, significantly increasing surface area.

While tapioca pearls are 100 percent starch, corn grits also contain fiber, protein and other substances that are not efficient for absorbing water.

Starch-based adsorbents like tapioca pearls also take up the heat created during drying, allowing that heat to be reused to evaporate water during regeneration of the drying bed.

"This combines fundamental biochemistry, biology and engineering with thermodynamics to obtain an efficient separation system," Ladisch said.

After trying several options to maximize water absorption, including corncobs and wood chips, inspiration struck Ladisch while watching his mother-in-law fix Thanksgiving dinner. As she started mixing up homemade tapioca pudding, Ladisch noticed that the tapioca pearls looked similar to the beads used in molecular sieves.

"I started thinking, 'It's a starch. Might this work?'" Ladisch said.

Ladisch said tapioca pearls may be used effectively in U.S. ethanol facilities, but he believes they could be more significant in facilities in South America and Africa where the plant used to create tapioca - cassava - is grown.

Ladisch and Kim said they would continue to test uses for tapioca pearls, including drying other alcohols. They also plan to create synthetic, starch-based adsorbents from other cheaper materials to lower the cost.

Ladisch is chief technology officer at Mascoma, a renewable fuels company based in New Hampshire. He received no funding from the company for this research. Archer Daniels Midland funded the work.

More information: ABSTRACT

Cassava Starch Pearls as a Desiccant for Drying Ethanol

Youngmi Kim, Rick Hendrickson, Nathan Mosier, Ahmad Hilaly,
and Michael R. Ladisch

The fuel ethanol industry uses corn grits packed in fixed bed adsorption towers to dry hydrous ethanol vapors in an energy efficient manner. Spherical micropearl cassava starch exhibit a higher adsorption capacity than corn grits of the same size and may be a viable replacement for ground corn. Adsorption equilibrium curves, BET surface area measurements, and SEM images provide an explanation for the enhanced performance of cassava micropearls based on particle architecture and the surface area available to water molecules. The SEM images show that the micropearls form a core–shell structure with pregel starch acting as the scaffold that holds starch granules in an outer layer. This layer determines the BET surface area and the measured equilibrium adsorption capacity. The core–shell microstructure results in a shortened diffusion path-length and enhanced adsorption rates. These microstructural and operational characteristics provide a template for microfabrication of enhanced capacity starch based spherical adsorbents that could replace ground corn for the drying of ethanol.

Provided by Purdue University (news : web)

Reverse engineering materials with a rapid, non-destructive laser-based technique can aid the fight against counterfeits

In business, protecting a company’s intellectual property can mean the difference between market success and bankruptcy. As the threat of competition from illegal copies of patented technology grows, high-tech firms are themselves turning to reverse engineering to spot potential patent infringements. Effendi Widjaja and Marc Garland from the A*STAR Institute of Chemical and Engineering Sciences have now developed a technique that promises to revolutionize reverse-engineering protocols—a rapid, non-destructive approach for mapping the composition of multilayered materials.

Multilayer films are used in the lamination of electronic components as well as sport equipment, providing multifunctional protection that single-layer films cannot, such as water and corrosion resistance, for example. Identifying the composition of these films, however, usually involves chopping the sample up and dissolving it in solvents, a destructive and labor-intensive process. Widjaja and Garland have developed a non-destructive reverse-engineering strategies based on vibrational spectroscopy and advanced signal processing.

Scientists have long known that when excited by light, molecules emit vibrational signals that provide detailed information on their chemical and structural environments. Raman spectroscopy is a laser-based version of such a techniques that can be used with very little sample preparation and provides high precision. The difficulty in applying such analyses to multilayer films has been the volume of data generated—particles in a multilayer films have a wide range of overlapping vibrational signals, resulting in a complex readout that is hard to assign to individual substances.

Widjaja and Garland overcame this challenge by developing an algorithm called band-target entropy minimization (BTEM), in which rigorous statistical equations are used to ascertain the simplest sets of ‘pure’ component patterns within a vibrational spectrum. The program is extraordinarily sensitive to trace components within a material: it has been show in previous studies that even substances contributing less than 1% to the total vibrational signal information can be recovered by BTEM.

The team tested their strategy by attempting to reverse engineer the multilayer structure of a commercial packaging envelope. After shining the Raman beam onto the sample, the BTEM algorithm detected seven underlying patterns in the spectra. These patterns correspond to two forms of paper fiber, three inorganic crystalline materials and two polymers. By distributing each pure signal across the sample’s dimensions, the team successfully reconstructed the spatial distributions of the components in each laminated layer.

The speed and precision of the Raman/BTEM analysis, Widjaja and Garland note, makes the technique a valuable weapon in the fight against patent infringement.

More information: Widjaja, E. & Garland, M. Reverse engineering of multi-layer films. Materials Today 14, 114–117 (2011).

Provided by Agency for Science, Technology and Research (A*STAR)

'Super-spaghetti' with heart-healthy label now possible

Consumers could soon see packages of pasta labeled "good source of dietary fiber" and "may reduce the risk of heart disease" thanks to the development of a new genre of pasta made with barley—a grain famous for giving beer its characteristic strength and flavor. The report appears in ACS' Journal of Agricultural and Food Chemistry.

Vito Verardo, Ana Maria Gómez-Caravaca and colleagues explain that barley, a grain that is an excellent source of fiber and antioxidants, is gaining interest as an ingredient in so-called "functional foods" — a genre of foods that are supplemented with healthful additives. The functional foods craze began in Japan in the mid-1980s and caught on around the world with health-conscious consumers, creating a fast-growing industry that is expected to reach over $176 billion by 2013. Barley is already added to some bakery products. To determine whether barley could make a new functional spaghetti by providing fiber and antioxidants, the researchers developed a barley flour, that contains the most nutritious part of the grain and used it to make pasta. This flour corresponds to the barley by-products and has been obtained by an healthy separation method such as the air classification.

They found that the barley spaghetti had more fiber and more antioxidant activity than traditional semolina-based spaghettis. Adding gluten to barley flour improved the cooking quality of the , but lowered its antioxidant activity.

More information: Development of Functional Spaghetti Enriched in Bioactive Compounds Using Barley Coarse Fraction Obtained by Air Classification, J. Agric. Food Chem., 2011, 59 (17), pp 9127–9134. DOI: 10.1021/jf202804v

Barley byproducts obtained by air classification have been used to produce a different barley functional spaghetti, which were compared to different commercial whole semolina samples. Total, insoluble, and soluble fiber and ß-glucan contents of the barley spaghetti were found to be greater than those of commercial samples. Furthermore, it was proved that barley spaghetti reached the FDA requirements, which could allow these pastas to deserve the health claims “good source of dietary fiber” and “may reduce the risk of heart disease”. When the barley coarse fraction was used, a flavan-3-ols enrichment and an increase of antioxidant activity were reported, while commercial samples showed the absence of flavan-3-ols and a higher presence of phenolic acids and tannins. Whole semolina commercial spaghetti had a significantly higher content of phenolic acids than semolina spaghetti samples. Besides, it was observed that when vital gluten was added to the spaghetti formulation, phenolic compounds were blocked in the gluten network and were partially released during the cooking process.

Provided by American Chemical Society (news : web)