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Biosilicification: the role of the organic matrix in structure control.

Silicon (although never in the elemental form) is present in all living organisms and is required for the production of structural materials in single-celled organisms through to higher plants and animals. Hydrated amorphous silica is a mineral of infinite functionality and yet it is formed into structures with microscopic and macroscopic form. Research into the mechanisms controlling the process have highlighted proteins and proteoglycans as possible control molecules. Such molecules are suggested to play a critical role in the catalysis of silica polycondensation reactions and in structure direction. This article reviews information on silica form and function, silica condensation chemistry, the role of macromolecules in structure control and in vitro studies of silica formation using biomolecules extracted from biological silicas. An understanding of the mechanisms by which biological organisms regulate mineral formation will assist in our understanding of the essentiality of silicon to life processes and in the generation of new materials with specific form and function for industrial application in the 21st century.

Animals↗

Poly(ethylene glycol)-salt aqueous two-phase systems with easily recyclable volatile salts.

Aqueous two-phase systems (ATPSs) have great potential in the downstream processing of fermentation products. However, the consumption of large amounts of auxiliary materials limits application in industrial practice. Promising alternatives to the salts used so far are volatile salts such as ammonium bicarbonate and ammonium carbamate, which can be recycled to the extraction system as gaseous carbon dioxide and ammonia. In this work, it is demonstrated that ammonium carbamate in combination with poly(ethylene glycol) (PEG, molecular masses of 2000, 4000 and 10000) indeed produces aqueous two-phase systems (ATPSs) at a temperature of 25 degrees C and atmospheric pressure. Ammonium bicarbonate is clearly not suitable as a phase-forming salt, because of its too-low solubility in water.

Carbamates↗

Spherical alginate granules formulated for quick-release active subtilisin.

Novel attrition-resistant and spherical enzyme granules encapsulating active subtilisin were formed by emulsification of 2% alginate sol loaded with active enzyme, instantaneous gelation triggered through in situ release of Ca(2+) (internal gelation), particle separation, and finally acetone extractive drying. Granular subtilisin was highly active, readily dispersible, and mechanically robust. This technique serves as a new and attractive alternative to established enzyme granulation processes, such as fluid bed coating, extrusion followed by marumerization, drum granulation, or prilling, for use in industrial enzyme applications such as detergents, textile manufacturing, and food processing. The formulation and encapsulation conditions were optimized to maximize the resistance of the granule to compression and impact forces, consistent with enzyme release and particle dispersion in detergent solutions. Well characterized alginates, with specified guluronic/mannuronic acid (G/M) content and molecular weight, were used in the formulation. The characteristics of the resulting microspheres, including their size and distribution, morphology, shrinkage, compression resistance, impact strength, solubility and encapsulation yield, were examined. Spherical dry granules were formulated with a mean diameter of 500 microm with particle sizes ranging from 300 to 800 microm. Dry alginate granules were discrete, spherical, and glossy white and exhibited impact strength, compression resistance, and solubility difference dependent on composition. Reduced starch levels, high alginate concentration, low alginate molecular weight, and use of high guluronate alginates resulted in the lowest dust level and highest compression resistance. Subtilisin mass yields were approximately 50%, and specific activity yields ranged from 60% to 100%. A formulation consisting of 3% SG150 alginate, 10% starch, 10% TiO(2), and 1% CaCO(3) provided granules appropriate for use in detergent application.

Alginates↗

Solvent extraction employing a static micromixer: a simple, robust and versatile technology for the microencapsulation of proteins.

The potential of a static micromixer for the production of protein-loaded biodegradable polymeric microspheres by a modified solvent extraction process was examined. The mixer consists of an array of microchannels and features a simple set-up, consumes only very small space, lacks moving parts and offers simple control of the microsphere size. Scale-up from lab bench to industrial production is easily feasible through parallel installation of a sufficient number of micromixers ('number-up'). Poly(lactic-co-glycolic acid) microspheres loaded with a model protein, bovine serum albumin (BSA), were prepared. The influence of various process and formulation parameters on the characteristics of the microspheres was examined with special focus on particle size distribution. Microspheres with monomodal size distributions having mean diameters of 5-30 micro m were produced with excellent reproducibility. Particle size distributions were largely unaffected by polymer solution concentration, polymer type and nominal BSA load, but depended on the polymer solvent. Moreover, particle mean diameters could be varied in a considerable range by modulating the flow rates of the mixed fluids. BSA encapsulation efficiencies were mostly in the region of 75-85% and product yields ranged from 90-100%. Because of its simple set-up and its suitability for continuous production, static micromixing is suggested for the automated and aseptic production of protein-loaded microspheres.

Animals↗

Occupational rhinoconjunctivitis from white pepper.

A 44-year-old subject developed rhinoconjunctivitis symptoms when she was exposed to white pepper while working in the food industry. A positive skin prick test for white and black pepper extracts (1:10 w/v) were obtained. Specific IgE antibodies to white and black pepper were demonstrated by ELISA. The immunoblot analysis showed two IgE-reactive protein bands able to bind to IgE from white pepper extract of 11.8 kDa and 13.6 kDa and one band from black pepper extract of 11.8 kDa. IgE binding to blotted white and black pepper extract were inhibited by preincubation of patient serum with black pepper extract. A conjunctival provocation test was positive with a white pepper extract dilution of 1:100 w/v. We describe a patient with occupational rhinoconjunctivitis caused by hypersensitivity to white pepper.

Adult↗

[History of gelatin extraction process and debates of French academic commissions (XIXth century)].

Since Papin (XVII th century) gelatine was expected to be substituted for meat in poor peoples' food. Its nutritional value was studied by academic Commissions, from 1803 to 1841. The question has been given up after 1870 when the growth in agricultural yield owing to fertilizer use made food shortage vanish. In this paper, successive extraction methods are examined, and Chevreul's participation in the academic debates (XIX th century) is emphasized.

Food Handling↗

Carrageenans and their use in meat products.

Carrageenans are sulfated linear polysaccharides of D-galactose and 3,6-anhydro-D-galactose extracted from red seaweeds. They have been used by the food industry for their gelling, thickening, and stabilizing properties, and more recently by the meat industry for reduced fat products. Meat is a complex system of muscle tissue, connective tissue, fat, and water; during processing, numerous interactions occur among all these components. These interactions are responsible for the functional properties of the meat system. In meat products, carrageenans contribute to gel formation and water retention. Their addition is of special interest in low-fat meat products because fat reduction often leads to unacceptable, tough textures. When carrageenans are incorporated in these formulations, they improve the textural characteristics of the product by decreasing toughness and increasing juiciness. Although carrageenan interactions with milk proteins have been studied extensively, the mechanism by which carrageenans interact with meat proteins and the other meat components is not fully understood.

Carbohydrate Conformation↗

Assessment of the trace organic molecular composition of industrial and municipal wastewater effluents by capillary gas chromatography/real-time high-resolution mass spectrometry: a preliminary report.

In summary, the use of HRGC/HRMS and ECC can provide valuable information on the organic constituents of refinery wastewater samples, even when present in extremely complex mixtures. In many cases, the low-resolution (nominal mass) spectra would not have been interpretable without the availability of the corresponding high-resolution (accurate mass and elemental composition) information, since, even with the use of capillary columns, the components of these complex mixtures were not chromatographically resolved. It is apparent that additional components in these fractions could be identified if additional data processing followed by detailed analysis of the ECC data set is carried out incorporating the retention index information derivable from the series of n-alkanes present, although the incomplete chemical fractionation of the samples is a complicating factor in these particular wastewater extracts.

California↗

Heap leaching of Pb and Zn contaminated soil using ozone/UV treatment of EDTA extractants.

The feasibility of a novel EDTA-based soil heap leaching method with treatment and reuse of extractants in a closed process loop was evaluated on a laboratory scale. Ozone and UV irradiation were used for oxidative decomposition of EDTA-metal complexes in extractants from Pb (1243 mg kg(-1)) and Zn (1190 mg kg(-1)) contaminated soil. Released metals were absorbed in a commercial metal absorbent Slovakite. Six-consecutive additions of 2.5 mmol kg(-1) EDTA (total 15 mmol kg(-1) EDTA) removed 49.6 +/- 0.6% and 19.7 +/- 1.7% of initial total Pb and Zn from soil (4.6 kg) packed in 22 cm high columns. The efficiency of extraction was similar to small-scale simulations of heap leaching (15 0 g of soil), where EDTA used in the same manner removed 49.7 +/- 1.0% and 13.7 +/- 0.4% of Pb and Zn. The new heap leaching method produced discharge extractant with fairly low final concentrations of Pb, Zn and EDTA (1.98 +/- 2.17 mg l(-1), 4.55 +/- 2.36 mg l(-1), and 0.05 +/- 0.04 mM, respectively), which could presumably be reduced even further with continuation of treatment. The results of our study indicate that for soils contaminated primarily with Pb, treating the EDTA extractants with ozone/UV and reuse of extractants enables efficient soil heap leaching with very little or no wastewater generation, easy control over emissions, and lowers the requirements for process water.

Calcium↗

Extractive purification of enzymes from animal tissue using aqueous two phase systems: pilot scale studies.

Pilot scale trials have been carried out to assess the feasibility of using PEG-salt aqueous phase systems for extraction and purification of enzymes from animal tissue on an industrial scale. Comminuted bovine liver was used as a starting material, and it was easy to separate a clear upper phase containing proteins of interest from a mixture containing 20% biomass, 15% PEG and 8% phosphate using a disc separator. Similar attempts with decanters were unsuccessful. Second-phase separation was simply accomplished by the addition of salt to the separated, clear upper layer and standing or allowing passage through a disc separator. The method was tested using continuous mixing on the GBF continuous mixing aqueous phase extraction plant, with and without computer control. Good separations were achieved. The enzyme superoxide dismutase was purified using this method yielding a 4-fold purification factor with respect to soluble protein and a recovery rate of 83%, with the enzyme in a clarified solution suitable for further processing by chromatographic methods. The general applicability of this method, its economics and its potential application in industry are discussed.

Animals↗

Effects of processing on pesticide residues in peaches intended for baby food.

Peaches containing added residues of chlorpyrifos-methyl, fenitrothion, procymidone and vinclozolin were used for simulated industrial processing in the manufacture of baby food puree. Residues were determined in raw material, in intermediate products at crucial steps of the processing procedure and in final products. Determination of residues was performed by an analytical method, distinguished by high sensitivity, based on acetone extraction, a two-step clean-up/pre-concentration on graphitized carbon and SAX/PSA sorbent, and GC-ECD. The results of the study were interpreted with respect to enforcement of the stringent Maximum Residue Limit (MRL) of 0.01 mg kg-1 established by the European Commission (EC) for any pesticide in baby food. Peeling was identified as the most effective procedure in reducing residues. Thermal treatment (concentration and sterilisation) substantially reduced organophosphate (chlorpyrifos-methyl, fenitrothion) residues, whereas procymidone and vinclozolin residue levels were increased in peach puree.

Food Analysis↗

Enzyme inactivation analyses for industrial blanching applications employing 2450 Mhz monomode microwave cavities.

Browning reactions in fruits and vegetables are recognized as a serious problem for the European food industry, particularly for the mushroom sector. The major enzyme responsible for the browning reaction is polyphenoloxidase (PPO). In this paper considerable reduction has been achieved in both the time and temperature required for complete microwave enzyme inactivation compared to conventional hot-water treatments, which can be translated into both increased benefits and enhanced quality products for the food industry. Furthermore, the short exposure time required for complete inactivation of aqueous solutions of PPO irradiated with microwaves within monomode cavities is very important to reduce the browning rate of mushroom extracts, and could lead to a much greater product profitability when treating whole processed mushrooms.

Agaricales↗

[Influence of technological processing on various nutritional characteristics of sunflower protein isolates].

The composition and nutritional value of sunflower meals and protein isolates were determined. One of the meals was an ordinary industrial one (HI) and the other (HL) was prepared at the laboratory from the same batch of sunflower seeds. The protein isolates were obtained from both meals (AHI and AHL, respectively) and from the original seeds (AS), by means of a process employing water extraction and precipitation at pH 4.3. Chemical analysis of both meals showed that their moisture, protein crude fiber and fat contents had no significant difference. Sulphur amino acids (g/16 g N) were higher in the isolates than in the flours. The HL flour, and the AHL and AS isolates had a higher proportion of available lysine (96.9%, 93.0%, and 92.4% respectively) than the HI flour and AHI isolate. This improvement of protein quality was attained by the employment of less drastic thermal treatments in their preparation, as compared with the treatments to which other materials were submitted.

Amino Acids, Sulfur↗

Viral validation of the manufacturing process of high purity albumin from placentas.

We report on the viral validation of an industrial purification process which is used to manufacture high purity human albumin from frozen placentas. This process has been used without any modification since 1980 except for a progressive increase in production scale to reach a capacity of 19 tons of placentas per day. The extraction purification process includes five alcohol manufacturing steps, some with strict conditions of alcohol concentration, acid pH, temperature and one including chloroform. These steps are followed by three chromatographies. Albumin is finally submitted to pasteurization both in bulk and in the final container. Selected steps of this process have been tested for their ability to remove or inactivate viruses. Viruses used were HBV, HIV-1, HIV-2 and model viruses poliovirus, avian reovirus, MuLV, Sindbis, SV40 and Aujeszky's. In vitro infectivity titration assays were used for all viruses except for HBV where DNA and antigen titrations were performed. Reduction factors obtained were from 10 to 29 log10 depending on the viral marker. Moreover, testing done on regular production batches demonstrated the absence of HBV, HIV-1 and HCV genomic sequence in the final lots. Viral risk calculation for HBV, HIV-1 and HCV was made considering the maximal theoretically possible contamination of the starting material. This calculation showed the very large safety margin the manufacturing process with respect to virus transmission for these viruses or possibly other unknown ones.

Albumins↗

MDI Exposure for Spray-On Truck Bed Lining.

Worker exposure to MDI (methylenediphenyl isocyanate) in the sprayed-on truck bed lining industry was assessed by examining Washington State OSHA inspection files and industrial insurance records. The industry uses MDI to form a protective urethane coating on pick-up truck beds. The lining is applied by a worker using a handheld spray gun with application equipment at temperatures and pressures specified by the urethane supplier. Inspections with MDI sampling were initially identified by searching the agency's laboratory database and were further screened for the targeted process. Data for 13 employers was found and extracted from the inspection records. All were small companies with only 1 to 2 workers exposed to MDI; 10 of the 13 employers had started the bed lining service within the last 4 years. The process was found in truck bed lining specialty shops as well as in other truck-related businesses. Six different urethane products were used with reported MDI monomer concentrations of up to 75 percent along with varying concentrations of MDI pre-polymers and other reactants and solvents. Sampling for MDI by inspectors found 7 worksites with worker exposure in excess of the state and OSHA ceiling limit of 0.200 mg/M(3). Deficiencies in respirator programs and engineering controls for MDI were cited. A review of the industrial insurance records found a total of five MDI-related claims at 4 inspected worksites, two for new-onset asthma. It was concluded that workers in the urethane sprayed-on truck bed lining industry are at an increased risk of developing illnesses associated with isocyanate exposure. Interventions are needed to further assess the hazard as well as motivate and assist franchisers, distributors, and retailers to implement effective engineering controls and respiratory protection programs in this nationally emerging small employer industry.

Aerosols↗

Acute respiratory effects in the potato processing industry due to a bioaerosol exposure.

The relation between bioaerosol exposure in the potato starch industry and work related respiratory symptoms is described. One group of workers was exposed to high dust concentrations (geometric mean up to 56.0 mg/m3) with low endotoxin and antigen concentrations (geometric mean up to 12.6 ng/m3 and 90 relative antigen units (RAU) per m3). A second group was exposed to low dust concentrations (geometric mean up to 3.9 mg/m3), but the endotoxin and antigen concentrations were high (geometric means of environmental samples up to 72 ng/m3 and 2.9.10(2)RAU/m3). Twenty of the 48 workers had specific IgG4 titres to dust extract. Of these 20 workers, 14 showed an increase in IgG4 titre during the first month of the potato processing season. No specific IgE antibodies to dust extracts were found. Twenty two workers were equipped with a Mini-Wright peak flow meter during a four week period. Two workers showed a work related decline in peak flow values. It was concluded that exposure to dust made airborne during the refining process of potato starch may cause work related respiratory symptoms.

Aerosols↗

Combined use of photosynthetic enzyme complexes and microalgal photosynthetic systems for rapid screening of wastewater toxicity.

Because of the often episodic nature of wastewater toxicity, routine monitoring using expensive and time consuming tests can constitute an inefficient means of toxicity evaluation, particularly when negative results are generated. Cost-effective screening tests enabling the rapid detection of effluent toxicity are clearly needed, and they should be used to rapidly determine where in-depth investigations should be focused. The LuminoTox is a recently-developed screening test enabling the rapid determination of wastewater toxicity. This test is based on the inhibition of chlorophyll fluorescence emitted by photosynthetic systems. The combined use of photosynthetic enzyme complexes (PECs), isolated from higher plants, and whole photosynthetic organisms (algae) allows a wide range of toxic inhibitors to be detected within 10-15 min. The detection thresholds obtained for individual toxic chemicals indicate that algae are less sensitive to metal cations than PECs, because of the algal cell wall being ion selective. However, other toxic chemicals, such as phenolic compounds and nitrogen ammonia, acting on the last constituents of the photosynthetic enzyme complex that are degraded during the PEC extraction process, are more easily detected with algae after just 10 min of exposure. The combination of PECs and algae is not only useful for rapid toxicity screening, but yields results that are as sensitive as those of standard bioassays. Toxicity data generated with mining industry effluents demonstrate that PECs routinely prove to be as sensitive as daphnia, while algal sensitivity is comparable to that of the standard trout bioassay. An important feature of LuminoTox and algal photosynthetic system testing, however, resides in the production of their rapid and sensitive responses (10-15 min) in comparison with those of the more traditional tests (48-96 h for daphnia and trout, respectively).

Eukaryota↗

The role of natural product chemistry in drug discovery.

Although traditionally natural products have played an important role in drug discovery, in the past few years most Big Pharma companies have either terminated or considerably scaled down their natural product operations. This is despite a significant number of natural product-derived drugs being ranked in the top 35 worldwide selling ethical drugs in 2000, 2001, and 2002. There were 15 new natural product-derived drugs launched from 2000 to 2003, as well as 15 natural product-derived compounds in Phase III clinical trials or registration at the end of 2003. Recently, there has been a renewed interest in natural product research due to the failure of alternative drug discovery methods to deliver many lead compounds in key therapeutic areas such as immunosuppression, anti-infectives, and metabolic diseases. To continue to be competitive with other drug discovery methods, natural product research needs to continually improve the speed of the screening, isolation, and structure elucidation processes, as well addressing the suitability of screens for natural product extracts and dealing with issues involved with large-scale compound supply.

Biological Factors↗