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PubMed1992

Adsorption of polycyclic aromatic hydrocarbons (PAHs) by soil particles: influence on biodegradability and biotoxicity.

Polycyclic aromatic hydrocarbon (PAH) biodegradation was investigated in contaminated soils from two different industrial sites under simulated land treatment conditions. Soil samples from a former impregnation plant (soil A) showed high degradation rates of PAHs by the autochthonous microorganisms, whereas PAHs in material of a closed-down coking plant (soil B) were not degraded even after inoculation with bacteria known to effectively degrade PAHs. As rapid PAH biodegradation in soil B was observed after PAHs were extracted and restored into the extracted soil material, the kind of PAH binding in soil B appears to completely prevent biodegradation. Sorption of PAHs onto extracted material of soil B follows a two-phase process (fast and slow); the latter is discussed in terms of migration of PAHs into soil organic matter, representing less accessible sites within the soil matrix. Such sorbed PAHs are suggested to be non-bioavailable and thus non-biodegradable. By eluting soil B with water, no biotoxicity, assayed as inhibition of bioluminescence, was detected in the aqueous phase. When treating soil A analogously, a distinct toxicity was observed, which was reduced relative to the amount of activated carbon added to the soil material. The data suggest that sorption of organic pollutants onto soil organic matter significantly affects biodegradability as well as biotoxicity.

Adsorption↗
PubMedDate not supplied

Multiresidue determination of 19 fungicides in processed fruits and vegetables by capillary gas chromatography after gel permeation chromatography.

A gas chromatographic (GC) method was developed for simultaneous determination of 19 fungicides (chlorothalonil, vinclozolin, dichlofuanid, triadimefon, penconazole, chlozolinate, captan, procymidone, triadimenol, folpet, hexaconazole, myclobutanil, cyproconazole, propiconazole, nuarimol, captafol, iprodione, fenarimol, and bitertanol) and the acaricide tetradifon in tomato puree, peach nectar, orange juice, and canned peas. Samples were extracted with acetone, partitioned with ethyl acetate-cyclohexane (50 + 50, v/v), and cleaned using gel permeation chromatography with ethyl acetate-cyclohexane (50 + 50, v/v) as eluant. The final extract was analyzed by GC with ion trap mass spectrometry (ITMS) using a DB5 capillary column. Recoveries from fortified samples ranged from 74.6 to 99.3%, except for triadimenol and bitertanol. Quantitation limits for most analytes were between 0.005 and 0.050 mg/kg. The purified extracts were analyzed further by GC with electron capture and nitrogen phosphorus detection, and the results were compared with those obtained by ITMS.

Chromatography, Gas↗
PubMed2006

Recent advances in polyhydroxyalkanoate production by mixed aerobic cultures: from the substrate to the final product.

Numerous bacteria have been found to exhibit the capacity for intracellular polyhydroxyalkanoates (PHA) accumulation. Current methods for PHA production at the industrial scale are based on their synthesis from microbial isolates in either their wild form or by recombinant strains. High production costs are associated with these methods; thus, attempts have been made to develop more cost-effective processes. Reducing the cost of the carbon substrates (e.g., through feeding renewable wastes) and increasing the efficiency of production technologies (including both fermentation and downstream extraction and recovery) are two such examples of these attempts. PHA production processes based on mixed microbial cultures are being investigated as a possible technology to decrease production costs, since no sterilization is required and bacteria can adapt quite well to the complex substrates that may be present in waste material. PHA accumulation by mixed cultures has been found under various operational conditions and configurations at both bench-scale and full-scale production. The process known as "feast and famine" or as "aerobic dynamic feeding" seems to have a high potential for PHA production by mixed cultures. Enriched cultures submitted to a transient carbon supply can synthesize PHA at levels comparable to those of pure cultures. Indeed, the intracellular PHA content can reach around 70% of the cell dry weight, suggesting that this process could be competitive with pure culture PHA production when fully developed. Basic and applied research of the PHA production process by mixed cultures has been carried out in the past decade, focusing on areas such as microbial characterization, process configuration, reactor operational strategies, process modeling and control, and polymer characterization. This paper presents a review of the PHA production process with mixed cultures, encompassing the findings reported in the literature as well as our own experimental results in relation to each of these areas.

Bacteria, Aerobic↗
PubMed1989

Relationship of byssinosis to the generation of oxygen radicals by bract tissues of cotton plants.

Byssinosis is a hazardous respiratory disorder of workers in natural fiber processing industries and, in the case of cotton, is caused by exposure to respirable dust generated from leafy trash associated with raw fibers. To understand the chemical characteristics of involucral trash components that might contribute to bysinosis, we examined the human airway constricting activity and oxygen radical generating activity of dry, frost-killed cotton bracts. In response to inhalation of aerosolized bract extracts, the expiratory flow rates of human volunteers at 40% of vital capacity during partial forced expiration decreased by 3 to 32%. These values enabled us to identify two potentially byssinogenically active bract specimens, a specimen virtually inactive, and a fourth intermediately so. Using spin trapping techniques of electron spin resonance spectrometry, we found that all specimens catalyzed the generation of hydroxyl (preponderantly) and superoxide radicals from hydrogen peroxide. However, the weakest constrictor was the most potent catalyst, and vice versa. This was consistent with transition metal content of the specimens; the most potent catalyst also contained the largest amounts of those metals, suggesting a Fenton-type reaction mechanisms. Other possibilities for the inverse relationship of airway constricting (byssinogenic) activity with oxygen radical generation are discussed. We also found that neither aflatoxin nor endotoxin, contingent contaminants of bracts, catalyzed oxygen radical production from hydrogen peroxide.

Aflatoxin B1↗
PubMed2001

Evaluation of immobilized metal affinity chromatography for purification of penicillin acylase.

The aim of this work was to test immobilized metal affinity chromatography (IMAC) for the purification of penicillin acylase. After evaluation of different metals, Cu2+ was selected. Different samples were tested: pure penicillin acylase, industrial clarified feedstock and crude extract. After comparing two eluents, NH4Cl and imidazole, it appeared that although both gave good results for recovery and activity, NH4Cl was a more selective eluent with a higher fold purification than imidazole (4.64 versus 2.04). Moreover, we shown that a multistep gradient of NH4Cl, greatly increased the degree of purification (12.36) compared with the one-step process as control (4.64). In addition, good recovery was obtained (97-100%).

Animal Feed↗
PubMed2000

Diacetyl and alpha-acetolactate overproduction by Lactococcus lactis subsp. lactis biovar diacetylactis mutants that are deficient in alpha-acetolactate decarboxylase and have a low lactate dehydrogenase activity.

Lactococcus lactis subsp. lactis biovar diacetylactis strains are utilized in several industrial processes for producing the flavoring compound diacetyl or its precursor alpha-acetolactate. Using random mutagenesis with nitrosoguanidine, we selected mutants that were deficient in alpha-acetolactate decarboxylase and had low lactate dehydrogenase activity. The mutants produced large amounts of alpha-acetolactate in anaerobic milk cultures but not in aerobic cultures, except when the medium was supplemented with catalase, yeast extract, or hemoglobin.

Aerobiosis↗
PubMed2004

Evaluation of vinification lees as a general medium for lactobacillus strains.

Lactobacillus species present high nutritional requirements, so it is necessary to find new low-cost nutrient components for fermentation media. This work compares the utilization of vinification lees (an important residue of wineries) from red and white winemaking technology, distilled or not. An amount of 20 g of lees/L was used as the unique nutrient to obtain lactic acid from glucose using Lactobacillus strains with different properties: L. plantarum CECT-221, L. pentosus CECT-4023, L. casei CECT-5275, and L. coryniformis subsp. torquens CECT-25600. Only L. casei using distilled lees showed values (Pmax = 92.1 g/L and Y(P/S) = 1.05 g/g) similar to those obtained with the MRS broth. The UV spectra of white and red lees, distilled or not, allowed an interpretation of the different phenolic compounds present and their influence on the fermentation. Their detoxification by extraction with organic compounds and fermentation with L. pentosus was also considered. Time courses of glucose and lactic acid were modeled according to reported models to obtain more information about the process.

Culture Media↗
PubMed2004

Doping-control urinalysis of a ginseng extract, Cold-FX, in athletes.

Nutraceuticals may induce doping infractions through contamination of the product itself or their ingestion might be metabolized within the body to create a positive doping control test. We tested this possibility using a commercially available, proprietary ginseng root extract (Cold-FX, CV Technologies Inc., Edmonton, AB). After athletes ingested Cold-FX for 28 d at 400 mg/d, urine samples were collected and processed under strict IOC doping control guidelines and then analyzed for a full screen of IOC banned/restricted substances by an IOC-approved laboratory. There were no positive tests for any banned substances in any of the subjects. Our study demonstrates that ingestion of Cold-FX for 28 d at 400 mg/d does not represent a doping concern for athletes. Carefully controlled clinical studies like this one are necessary to provide the athlete, the nutraceutical industry and IOC regulatory bodies with information to avoid inadvertent exposure to banned/restricted or potentially unhealthy substances.

Adolescent↗
PubMed2002

Impacts of fly-ash on soil and plant responses.

Coal combustion produces carbon dioxides, SO x, NO x and a variety of byproducts, including fly-ash, flue gas and scrubber sludge. Fly-ash consists of minute glass-like particles and its deposition on leaves inhibits the normal transpiration and photosynthesis of plants. Fly-ash also affects the physicochemical characteristics of soil because it is generally very basic, rich in various essential and non-essential elements, but poor in both nitrogen and available phosphorus. The massive fly-ash materials have been a potential resource for the agricultural activities as well as the other industrial purposes. Practical value of fly-ash in agriculture as an 'effective and safe' fertiliser or soil amendment can be established after repeated field experiments. Here remains to be disclosed the biological processes and interactions due to 'lack and excess' of the fly-ash exposures along with abiotic and biotic factors. These may involve the symbiotic fixation of nitrogen and the biological extraction of metals following immobilisation of toxic heavy metal ions, as well as other neutralisation and equilibration processes during weathering. Nitrogen-fixing plants with an apparent heavy metal-tolerance can be helpful as the early colonisers of fly-ash dumps and nearby areas.

Journal Article↗
PubMed2000

Beef allergy in children.

Beef allergy was poorly known before the '90s. Since then, a number of papers appeared elucidating the nature, epidemiology, and symptoms of beef allergy in children allergic to cow's milk and children suffering from atopic dermatitis. It is now clear that beef allergy is not an infrequent occurrence, with an incidence between 3. 28% and 6.52% among children with atopic dermatitis, its incidence may be as much as 0.3% in the general population. A diagnosis of beef allergy must be supported by skin prick tests, RASTs, and challenges. The specificity and sensitivity according to type of test and the type of extract, however, remains to be evaluated. Despite the fact that other allergens can be sensitizing, the major beef allergen is bovine serum albumin (BSA). Beef-sensitive children are also sensitized to ovine serum albumin, as well as to other serum albumins; therefore, the use of alternative meats in beef-allergic children must be carefully evaluated on an individual basis. Because industrial heat processing is more efficient than domestic cooking in reducing reactivity in beef-sensitive children, freeze-drying and homogenization may support the introduction of processed beef into the diet of beef-allergic children.

Allergens↗
PubMed2002

Milk-arterial plasma transfer of PCDDs and PCDFs in pigs.

Polychlorodibenzo-para-dioxins (PCDDs) and Polychlorodibenzofurans (PCDFs) are ubiquitous in the environment. They are mainly formed as unwanted byproducts during various chemical, industrial, and combustion processes. Thus, these pollutants can be found in the food chain. The aim of this experiment was to study the transfer of PCDD/Fs from spiked milk to arterial blood in pigs, which are considered as valid models for humans. Pigs were fed with 900 mL of milk spiked with a mixture of 17 dioxins. The levels of PCDD/Fs in the serum extracts were determined using HRGC/HRMS prior to consumption of the milk, and at 3, 5, and 7 h after milk ingestion. Concentrations of PCDD/Fs in arterial plasma increased from 3 h to 5 h and decreased at 7 h. At time point 5 h, concentrations were found between 500 and 10000 pg x g(-1) fat. The transfer ratio < > was usually found between 0.7 and 3%. Related to the different milk concentrations, results of this study indicate a similar behavior of the studied molecules.

Absorption↗
PubMed2003

Fault detection and classification in chemical processes based on neural networks with feature extraction.

Feed forward neural networks are investigated here for fault diagnosis in chemical processes, especially batch processes. The use of the neural model prediction error as the residual for fault diagnosis of sensor and component is analyzed. To reduce the training time required for the neural process model, an input feature extraction process for the neural model is implemented. An additional radial basis function neural classifier is developed to isolate faults from the residual generated, and results are presented to demonstrate the satisfactory detection and isolation of faults using this approach.

Algorithms↗
PubMed1998

[Methods for extracting chitin from shrimp shell waste].

Shrimp shell waste obtained from several industrial freezing-purchasing plants of Guaymas, Sonora, Méx., was studied as a source of value-added chitin biopolymers. In part I, the effect of different isolation conditions on the chitin yield and chemical characteristic, was investigated. Protein and mineral matter were removed with alkali and acid treatment respectively. A 2x2x3 factorial a way of a completely randomized design was used in order to evaluate the effect of the process variables, namely, NaOH concentration (0.4 and 2%) during the deproteinization and HCl concentration (3 and 5%) carried out at 40, 50 and 60 degrees C. The best processing conditions were desproteinization with 2% NaOH, and demineralization with 5% HCl at 50 degrees C, in terms of final ash and chitin content and yield. In part II, a selection of methods of isolation of chitin and chitosan was studied in order to establish the best conditions for scaling up a process to pilot plant level. The processing conditions were selected from reported methods as well as from those defined in part I. Purity of chitin samples was determined in terms of residual protein, ash and chitin each one to produce high quality chitin (0.00% protein, 0.01% ash, 99.99% chitin) and standard grade chitin (0.00% protein, 0.09% ash, 99.13% chitin). Both products were considered as of adequate quality and their manufacture process could be scaled up by further optimization of the processing conditions.

Analysis of Variance↗
PubMed2005

Chemical and microbiological stability of waste sludge from paper industry intended for brick production.

Due to its chemical composition, waste sludge generated in the paper industry may be used as a raw material for brick production. Brick manufacture is limited to the warmer months of the year whereas sludge is produced continuously by different effluent treatment devices. Therefore, it has to be stored until further processing. For this reason, it is essential that it is not subject to significant chemical and microbiological decomposition during storage. In the experiment, sludge from a tissue paper mill was tested for its stability. It was stored for several weeks during winter and summer periods in a pile, 2 m in height, in an open but covered store. Different leachable organic and inorganic compounds indicating possible ongoing deterioration processes, as well as pH value, redox potential, temperature, humidity and dry matter content were evaluated weekly in water extracts of homogenized sludge samples. According to the test results, the material may be considered to be chemically and microbiologically stable as there was practically no emission of odorous and toxic compounds such as H2S, NH3 and butyric acid despite prolonged storage times and elevated environmental temperatures. All the microbial species identified in the sludge during storage belong to the typical microflora of the environment.

Bacteria, Aerobic↗
PubMed2001

Urinary concentrations of trichloroacetic acid in Danish workers exposed to trichloroethylene, 1947-1985.

BACKGROUND: Since 1947, the National Labour Inspection Service in Denmark has relied upon urinary measurements of trichloroacetic acid (TCA) in surveys of the occupational exposure to trichloroethylene (TCE). METHODS: We examined the paper files relating to 2397 TCA measurements to extract information about the year, the company, the work process and the worker. We used multiple regression models to analyze the effects of various factors on the urinary concentration of TCA. RESULTS: The regression analyses showed that (1) a four-fold decrease in TCA concentrations occurred from 1947 to 1985; (2) the highest concentrations were observed in the iron and metal, chemical, and dry cleaning industries; (3) TCA levels were two times higher among men compared with women in the iron and metal and dry cleaning industries; (4) TCA concentrations were higher among younger compared with older workers; and (5) persons working in an area in which TCE was used, but not working with TCE themselves, also showed urinary TCA levels indicative of exposure. CONCLUSIONS: Calendar year, type of industry, degree of contact with TCE, sex and age were predictors of TCA concentration in the urine of Danish workers.

Denmark↗
PubMed1981

Modification of technological properties of fish protein concentrates.

Fish protein concentrates are mixtures of cross-linked and aggregated molecules of different muscle proteins. The final conformation of the components of the mixtures is formed as a result of procedures applied to convert the raw materials into a product of desirable and stable sensory properties, containing less than 0.1% of lipids. To achieve this end usually extraction with hot organic solvents, mainly isopropyl alcohol and 1,2-dichloroethene, followed by air drying are employed. These conditions bring about denaturation of many of the proteins followed by aggregation of the molecules due to the interaction of reactive functional groups in extended polypeptide chains. In the final product a large proportion of hydrophobic groups is exposed to the solvent and the proteins exhibit an extremely low water affinity. Such concentrates, although valuable as protein supplements, have only limited suitability as active components of various processed foods, as they have poor technological value. They are insoluble or have a very low water dispersibility and swelling ability, do not form gels after heating, or have any significant fat-emulsifying capacity. Changing the dissociation or number of ionic groups of the molecules prior to extraction, e.g., by acidifying or acylating, can partially reduce the denaturing effect of heat and organic solvents and thus improve the functional properties of the product. An upgrading of the quality of concentrates produced by hot extraction can be achieved by partial enzymatic or chemical deaggregation, hydrolysis followed by the plastein reaction, or formation of suitable derivatives. The best results have been obtained by partial hydrolysis of acylated proteins or precipitation of the aggregated products using sodium hexametaphosphate. The functional properties of such products are comparable to those of vegetable protein isolates used as meat extenders. Various proteins of high technological value can be also obtained by enzymatic hydrolysis of the raw material, followed by separation of the lipids without organic solvent extraction. Such products, however, have a distinct odor and flavor and must be stabilized because of residual lipids.

Animals↗
PubMed2005

Inactivation of the BSE agent by the heat and pressure process for manufacturing gelatine.

Dietary exposure to the bovine spongiform encephalopathy (BSE) agent is the probable cause of variant Creutzfeldt-Jakob disease in people. The industrial manufacturing process for the production of gelatine and colloidal protein by the heat and pressure process was downscaled accurately and its capacity to remove or inactivate bse infectivity was investigated. Gelatine was made from bones experimentally contaminated with mouse brain infected with the 301V strain of mouse-passaged bse agent in which the infective titre was 10(8.7) ID50/g. No infectivity was detected in the extracted protein (> or =10(0.45) ID50/g), and the calculated clearance factor was 10(6.5) ID50 or more.

Animals↗
PubMed2004

[Validation of a method for discrimination of formaldehyde processing in textile products].

It is important to investigate a cause of formaldehyde contamination exceeding a regulation limit value in a textile product. If formaldehyde was released from a textile product itself by treatment or processing with formaldehyde, an administrative guidance is given to a manufacture. On the other hand, when the formaldehyde migrated from other textile products or a furniture stand during displaying, an improvement instruction is performed to the store. Iwama et al. [Ann. Rep. Nagoya City Public Res. Inst., 42, 11-16 (1996)] developed a method for distinguishing fabric processing and migration by additional hydrolytic extraction using hydrochloric acid solution. This study was to confirm the reliability and stability of the method for knowing formaldehyde processing on textiles. Five laboratories evaluated three samples: unprocessed textile, processed textile and unprocessed but formaldehyde-migrated textile. For a processed textile sample, amounts of formaldehyde increased by additional extractions with acidic solution, so all laboratories judged that the sample had been treated with formaldehyde. In the cases of the other two samples, such increases were not observed in the extracts using acidic solution. All laboratories reported that these samples were not processed using formaldehyde but had absorbed a different level of formaldehyde by migration. In a series of experiments, the judgement about the existence of formaldehyde processing or migration is comparatively consistent among all laboratories. This validation study concluded that the distinguishing method adopting additional extractions with acidic solution is useful to find formaldehyde processing of textile, and to deal with processing and migration separately as a cause of formaldehyde contamination.

Consumer Product Safety↗