Performance of four mixed-mode solid-phase extraction columns applied to basic drugs in urine.

Four different mixed-mode cation exchange solid-phase extraction columns were compared for extraction of basic drugs from urine using HPLC-DAD analysis: Isolute HCX-3, ABN, Bond Elut Certify and Oasis MCX. With one exception, all the studied drugs attained recoveries exceeding 50 % for all columns. We considered the following drugs: amphetamine, amlodipine, chlorprothixene, fentanyl, haloperidol, ketobemidone, methadone, mirtazapine, olanzapine, quetiapine, sertraline and zopiclone. The average recoveries for the four column types ranged from 68.5 % to 92.1 % in the experiments. In conclusion, the basic compounds performed reasonably well in all columns, and other factors, such as availability and price, may be decisive in regard to choice of column.

Wet oxidation treatment of organic household waste enriched with wheat straw for simultaneous saccharification and fermentation into ethanol.

Organic municipal solid waste enriched with wheat straw was subjected to wet-oxidation as a pre-treatment for subsequent enzymatic conversion and fermentation into bio-ethanol. The effect of temperature (185-195 degrees C), oxygen pressure (3-12 bar) and sodium carbonate (0-2 g l(-1) ) addition on enzymatic cellulose and hemicellulose convertibility was studied at a constant wet oxidation retention time of 10 minutes. An enzyme convertibility assay at high enzyme loading (25 filter paper unit (FPU) g(-1) dry solids (DS) added) showed that up to 78% of the cellulose and up to 68% of the hemicellulose in the treated waste could be converted into respectively hexose and pentose sugars compared to 46% for cellulose and 36% for hemicellulose in the raw waste. For all wet oxidation conditions tested, total carbohydrate recoveries were high (> 89%) and 44-66% of the original lignin could be converted into non-toxic carboxylic acids mainly (2.2-4.5 % on DS basis). Simultaneous saccharification and fermentation (SSF) of the treated waste at 10% DS by Saccharomyces cerevisae yielded average ethanol concentrations of 16.5 to 22 g 1(-1) for enzyme loadings of 5 and 25 FPU g(-1) DS, respectively. The cellulose to ethanol conversion efficiency during SSF was 50, 62, 65 and 70% for a total enzyme loading of 5, 10, 15 and 25 FPU g(-1) DS, respectively. Hence, this study shows that wet oxidation is a suitable pre-treatment for the conversion of organic waste carbohydrates into ethanol and that compatible conversion yields (60-65%) can be achieved at moderate enzyme loadings.

Inhibition of ethanol-producing yeast and bacteria by degradation products produced during pre-treatment of biomass.

An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible for ethanol fermentation. The resulting hydrolyzsates contain substances inhibitory to fermentation-depending on both the raw material (biomass) and the pre-treatment applied. An overview of the inhibitory effect on ethanol production by yeast and bacteria is presented. Apart from furans formed by sugar degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (Q(EtOH)) but not the ethanol yields (Y(EtOH)) in Saccharomyces cerevisiae. Within the same phenol functional group (aldehyde, ketone, and acid) the inhibition of volumetric ethanol productivity was found to depend on the amount of methoxyl substituents and hence hydrophobicity (log P). Many pentose-utilizing strains Escherichia coli, Pichia stipititis, and Zymomonas mobilis produce ethanol in concentrated hemicellulose liquors but detoxification by overliming is needed. Thermoanaerobacter mathranii A3M3 can grow on pentoses and produce ethanol in hydrolysate without any need for detoxification.

Potential inhibitors from wet oxidation of wheat straw and their effect on ethanol production of Saccharomyces cerevisiae: wet oxidation and fermentation by yeast.

Alkaline wet oxidation (WO) (using water, 6.5 g/L sodium carbonate and 12 bar oxygen at 195 degrees C) was used as pretreatment method for wheat straw (60 g/L), resulting in a hydrolysate and a cellulosic solid fraction. The hydrolysate consisted of soluble hemicellulose (8 g/L), low-molecular-weight carboxylic acids (3.9 g/L), phenols (0.27 g/L = 1.7 mM) and 2-furoic acid (0.007 g/L). The wet oxidized wheat straw hydrolysate caused no inhibition of ethanol production by Saccharomyces cerevisiae ATCC 96581. Nine phenols and 2-furoic acid, identified to be present in the hydrolysate, were each tested in concentrations of 50-100 times the concentration found in the hydrolysate for their effect on fermentation by yeast. At these high concentrations (10 mM), 4-hydroxybenzaldehyde, vanillin, 4-hydroxyacetophenone and acetovanillone caused a 53-67% decrease in the volumetric ethanol productivity in S. cerevisiae compared to controls with an ethanol productivity of 3.8 g/L. The phenol acids (4-hydroxy, vanillic and syringic acid), 2-furoic acid, syringaldehyde and acetosyringone were less inhibitory, causing a 5-16% decrease in ethanol productivity. By adding the same aromatic compounds to hydrolysate (10 mM), it was shown that syringaldehyde and acetovanillone interacted negatively with hydrolysate components on the ethanol productivity. Fermentation in WO hydrolysate, that had been concentrated 6 times by freeze-drying, lasted 4 hours longer than in regular hydrolysate; however, the ethanol yield was the same. The longer fermentation time could not be explained by an inhibitory action of phenols alone, but was more likely caused by inhibitory interactions of phenols with carboxylic acids, such as acetic and formic acid.

Potential inhibitors from wet oxidation of wheat straw and their effect on growth and ethanol production by Thermoanaerobacter mathranii.

Alkaline wet oxidation (WO) (using water, 6.5 g/l sodium carbonate, and 12 bar oxygen at 195 degrees C) was used for pre-treating wheat straw (60 g/l), resulting in a hemicellulose-rich hydrolysate and a cellulose-rich solid fraction. The hydrolysate consisted of soluble hemicellulose (9 g/l), aliphatic carboxylic acids (6 g/l), phenols (0.27 g/l or 1.7 mM), and 2-furoic acid (0.007 g/l). The wet-oxidized wheat straw hydrolysate caused no inhibition of ethanol yield by the anaerobic thermophilic bacterium Thermoanaerobacter mathranii. Nine phenols and 2-furoic acid, identified to be present in the hydrolysate, were each tested in concentrations of 10-100x the concentration found in the hydrolysate for their effect on fermentation by T. mathranii. At 2 mM, these aromatic compounds were not inhibitory to growth or ethanol yield in T. mathranii. When the concentration of aromatics was increased to 10 mM, the fermentation was severely inhibited by the phenol aldehydes and to a lesser extent by the phenol ketones. By adding the same aromatic compounds to WO hydrolysate (10 mM), synergistic inhibitory effects of all tested compounds with hydrolysate components were shown. When the hydrolysate was concentrated three- and six-fold, growth and fermentation with T. mathranii were inhibited. At a six-fold hydrolysate concentration, the total concentration of phenolic monomers was 17 mM; hence aromatic monomers are an important co-factor in hydrolysate inhibition.

[Isopods as fish parasites]. / Asseln als Fischparasiten.

In January '87 a parasitic isopod not previously described was discovered in the mouth of the fish species Cichla ocellatus from the South American river Demini, a tributary of the Rio Aracà. The parasite was classified as Telotha sp. A short description is given.

[Fish and natural protection]. / Fisch und Naturschutz.

Fish represent more than half of all vertebrates. They are the most important and most conspicuous creatures in the water. Their protection in the sense of the new animal protection law is therefore of course extremely difficult. Fish need protection just as much as other vertebrates. Fish suffer from harmful influences which should be eased or eliminated. They, like other vertebrates have highly sensitive sensory organs which react to stress through transport, encaging, pollution, and other similar factors. It is therefore an eminent task to protect them from these dangers. Possibilities are demonstrated to intensify the protection by a more thorough knowledge of their anatomy and physiology and their utilizationship with environment; cleaning the water, establishing natural protection areas, and controlling the situation within fish populations.

[A metacercarial disease in the dogfish species Umbra limi (Teleostei) and a trematode infestation in a Physa sp. (Mollusca)]. / Eine Metazerkarienerkrankung bei der Hundsfischart Umbra limi (Teleostei) und eine Trematodeninfestation bei einer Physa sp. (Mollusca).

A metacercarial infestation is reported in Canadian Umbra limi and a mass infestation by trematodes in Physa sp. from the same locality. Trials made by using parasitised snails showed that both parasites are not of the same species.