William N. Marmer

Lipase-catalyzed production of biodiesel

Lipases were screened for their ability to transesterify triglycerides with short-chain alcohols to alkyl esters. The lipase fromMucor miehei was most efficient for converting triglycerides to their alkyl esters with primary alcohols, whereas the lipase fromCandida antarctica was most efficient for transesterifying triglycerides with secondary alcohols to give branched alkyl esters. Conditions were established for converting tallow to short-chain alkyl esters at more than 90% conversion. These same conditions also proved effective for transesterfying vegetable oils and high fatty acid-containing feedstocks to their respective alkyl ester derivatives.

Reaction of Thiourea with Hydrogen Peroxide: 13C NMR Studies of an Oxidative /Reductive Bleaching Process

Thioureas reaction with hydrogen peroxide in solution under bleaching conditions at three different pH values has been investigated using 13C NMR spectroscopy. Since this reaction is fast and exothermic, it is essential that short total acquisition times be used to accumulate sufficient data to detect different species formed during the reaction. As the abundance of 13C in the reactants in the concentration range studied is very low, 13C-labeled thiourea was used as the starting material. Sufficient data were accumulated in short acquisition times (2–4 minutes) to identify different species formed during the reaction. The results showed that different intermediate products are formed during the reactions, depending on the pH of the medium and the molar ratio of the reactants. The reaction goes through a thiourea dioxide intermediate; this then hydrolyzes under heat and neutral or alkaline conditions to yield sulfonate anion and urea if the initial reaction of thiourea with hydrogen peroxide is allowed to take place in acidic/neutral medium (pH = 4.0–7.0). Because thiourea dioxide hydrolyzes in solution, there is a rapid change in redox potential from a positive value to a high negative value. The species causing the negative redox potential, and hence the species responsible for reductive bleaching, is believed to be the sulfinate anion. The reaction of thiourea with hydrogen peroxide in hydrochloric acid at pH < 1 results in the formation of formamidine disulfide dihydrochloride, which decomposes at pH values greater than 1.

Prion Infected Meat-and-Bone Meal Is Still Infectious after Biodiesel Production

The epidemic of bovine spongiform encephalopathy (BSE) has led to a world-wide drop in the market for beef by-products, such as Meat-and-Bone Meal (MBM), a fat-containing but mainly proteinaceaous product traditionally used as an animal feed supplement. While normal rendering is insufficient, the production of biodiesel from MBM has been suggested to destroy infectivity from transmissible spongiform encephalopathies (TSEs). In addition to producing fuel, this method simultaneously generates a nutritious solid residue. In our study we produced biodiesel from MBM under defined conditions using a modified form of alkaline methanolysis. We evaluated the presence of prion in the three resulting phases of the biodiesel reaction (Biodiesel, Glycerol and Solid Residue) in vitro and in vivo. Analysis of the reaction products from 263K scrapie infected MBM led to no detectable immunoreactivity by Western Blot. Importantly, and in contrast to the biochemical results the solid MBM residue from the reaction retained infectivity when tested in an animal bioassay. Histochemical analysis of hamster brains inoculated with the solid residue showed typical spongiform degeneration and vacuolation. Re-inoculation of these brains into a new cohort of hamsters led to onset of clinical scrapie symptoms within 75 days, suggesting that the specific infectivity of the prion protein was not changed during the biodiesel process. The biodiesel reaction cannot be considered a viable prion decontamination method for MBM, although we observed increased survival time of hamsters and reduced infectivity greater than 6 log orders in the solid MBM residue. Furthermore, results from our study compare for the first time prion detection by Western Blot versus an infectivity bioassay for analysis of biodiesel reaction products. We could show that biochemical analysis alone is insufficient for detection of prion infectivity after a biodiesel process.

Sequential Oxidative and Reductive Bleaching of Stained and Pigmented Wool in a Single Bath

A new process applicable to bleaching of both stained and pigmented wool combines a conventional bleaching process for pigmentation with a recently reported single- bath oxidative/reductive bleaching process. Conventionally, pigmented fibers in wool are selectively bleached by a three-step process: mordanting with ferrous ions, thorough and specific rinsing, and then bleaching with hydrogen peroxide. The process is de pendent on selective retention of ferrous species on melanin pigmentation, but some nonselective retention of ferrous ions on wool following rinsing leads, upon subsequent treatment with hydrogen peroxide, to an undesirable light brown discoloration from ferric species. The recently reported single-bath bleaching process, which was developed for stained wool, converts the unspent hydrogen peroxide of the initial oxidative bleaching step to a reductive substance in situ by reaction with thiourea followed by an appropriate pH adjustment to 7-8. When this process is combined with the ferrous mordanting procedure, pigmented and stained fibers are bleached, and any discoloring ferric species formed within the wool as a result of hydrogen peroxide are reduced to ferrous ions. Ferrous ions have a much lower affinity for wool than ferric ions and may be washed away easily. Overall, much superior bleaching with less physical damage is achievable by the new process than with conventional single- or multi-bath processes.

Pyrolysis Gas Chromatography of Wool Part I : Detection and Quantitation of Commercially Applied Agents

An investigation determined the feasibility of detecting and quantitating commer cially applied agents on wool by pyrolysis gas chromatography. Characteristic peaks were generated from benzoylated wool, from wool treated with the insect-resist agent Mitin FF and from wool dyed with Lissamine yellow 2G, thus demonstrating that the technique is suitable for detecting the presence of such agents. Two approaches were used for the quantitative analysis of the treatment and the dyeing using the data from the resulting pyrograms. One approach used peak area response per microgram of treated wool and the other used peaks generated from wools tyrosine as internal standards. Although the latter approach gave a better linear fit, inverse regression analysis demonstrated that the former approach was most suitable for predicting agent add-on (percent on weight of fiber).

Sequential Oxidative and Reductive Bleaching of Wool in a Single Bath

A new bleaching process applicable to wool was developed in which an oxidative step (hydrogen peroxide) is combined with a subsequent reductive step (thiourea, thiourea dioxide, or sodium hydroxymethanesulfinate) in a single-bath process. Ox idative followed by reductive bleaching is normally a two- or three-step treatment done in separate baths. Effective bleaching with reduced time and equipment use is achieved by the new single-bath process with a specific order of reagent addition. Although the reductive stage of such a single-bath process may be achieved by the complete decomposition of unspent hydrogen peroxide and then addition of reductive substances such as thiourea dioxide or sodium hydroxymethanesulfinate with necessary pH adjustment, one may take advantage of the unspent hydrogen peroxide to form a reductive substance in situ by reaction with thiourea followed by an appropriate pH adjustment to 7-8. In all the cases above, greatly superior bleaching with less physical damage is achieved with the new process compared with conventional single- or multi- bath processes.

Effect of Urea on Bleaching of Wool with Hydrogen Peroxide Under Alkaline and Acidic Conditions

The effect of urea on the alkaline and acidic hydrogen peroxide bleaching of wool has been investigated. There was an improvement in the whiteness of the wool or, alternatively, a considerable reduction in the bleaching time using a concentration of 100-200 g/l urea in the bleaching bath. No significant differences were observed at lower concentration of urea (less than 100 g/l) in the bleach bath. Alkali solubility of wool flannel increases with urea concentration during bleaching and often remains within tolerable limits.

HPLC of plasmalogen-containing phosphatidylcholine under reverse-phase or argentation conditions.

Two approaches to the high pressure liquid chromatography (HPLC) isolation of intact plasmalogens were investigated. The first used reversed-phase HPLC and sought to take advantage of subtle differences in the hydrophobicity of the alk-1-enyl chain from the acyl counterpart. On a C-18 column, bovine heart phosphatidylcholine (PC), which was 47% plasmalogen, was separated into a number of fractions that differed in their molecular species composition. One combination of fractions amounted to a 26% yield of PC enriched to 82% plasmalogen. The second approach sought to take advantage of the uniquely electron-rich functionality of the plasmalogens, the alk-1-enyl ether double bond, and its potential to coordinate with heavy metal ions. Specificially, bovine heart PC was applied to a cation-exchange type HPLC column in the silver ion mode. Although complete exchange of all the active sites of the column with silver ion led to complete retention of PC, partial activation with silver ion resulted in the separation of the PC into fractions, according to the degree of unsaturation. Plasmalogen-rich fractions eluted last and remained intact during the process. One combination of these fractions amounted to a 49% yield of PC enriched to 72% plasmalogen. Use of a cation-exchange system in the mercuric ion mode led to on-column hydrolysis of the plasmalogen; with palladium ion, the metallic species was stripped from the column by the eluting lipid.

Pyrolysis Gas Chromatography of Wool Part III: Detection and Quantitation of Tyrosine

Pyrolysis gas chromatography was used to study the content of tyrosyl residues in wool and the depletion of those residues by chemical reaction with nitrous acid. Wool samples that had undergone nitrosation of varying duration were analyzed by Curie- Point pyrolysis coupled with capillary column GC and flame ionization detection. The inertness of phenylalanyl residues to nitrosation permitted phenylalanine to be used as an internal standard. Peak areas for phenol and para-cresol—pyrolysis prod ucts—were compared to peak areas for phenylacetonitrile—a pyrolysis product of , phenylalanine. There was a linear relationship between the ratio of those peak areas and the molar ratio of Tyr / Phe, as determined by amino acid analysis, and another linear relationship for mixtures of known composition of polypeptides poly-tyrosine and poly-phenylalanine, but with a large difference in the slope from the line generated from the wool data. The difference was probably related to the relatively high con centration of terminal phenylalanyl groups in the polypeptide, which would result in the production of relatively larger amounts of phenylacetonitrile in the synthetic ma terial than in wool. The overall results demonstrated that damage to tyrosyl residues during the chemical processing of wool may be easily assessed using pyrolysis gas chromatography.

Nondestructive Measurement of Mechanical Properties of Wool Fabrics by an Acoustic Emission Method

The mechanical properties of textiles are important because they define many of the performance characteristics of end-products. Stress-strain tests are commonly used to measure tensile properties, but stress-strain curves of woven textiles are monotonic up to the breaking point and provide little information about events during stretching. We use acoustic emission spectroscopy to characterize the mechanical properties of a wide variety of materials, including some textiles. We investigate the mechanical properties of two woolen fabrics, correlating the stress-strain curves with acoustic emission events. Our results indicate that cumulative acoustic emission is a nondestructive indicator of incipient fabric damage and can be used as a quality control test in fabric manufacturing.