Biological recovery methods

The technologies used in the control of gaseous organic compound emissions include destruction methods such as thermal and catalytic incineration and biological gas treatment and recovery methods such as adsorption, absorption, condensation, and membrane separation. The most common control methods are incineration, adsorption, and condensation, as they deal with a wide variety of emissions of organic compounds. The most common types of control equipment are thermal and fixed-bed catalytic incinerators with recuperative heat recovery, fixed-bed adsorbers, and surface condensers. The control efficiencies normally range between 90% and 99%. 

For trace level analyses, acceptance criteria include 60-110% recovery for concentrations below 100 ppb, 80-100% recovery for concentrations above 100 ppb, and 70-120% for concentrations below 1 ppm. In biological samples, method accuracy for discovery phase investigations should be 20% of actual, with recoveries of 10% being necessary in preclinical and clinical smdies. Alternatively, it is recommended that the mean recovery value should be within 15% of actual, except at the quantitation limit where 20% is acceptable. 

Flavonoids can be determined quantitatively by direct (in glycoside or conjugated form) or indirect (after hydrolysis) analysis. However, sample preparation (e.g., particle size) and solvents used in extraction steps can significantly affect the results [99]. Method development for quantitation is often validated in terms of selectivity, accuracy, precision, recovery, calibration curve, and reproducibility. Biological sample methods have to comply with the Food and Drug Administration (FDA) guidelines for validation of bioanalytical method [100]. 

Biological products are normally produced in fermentation processes. The product is expressed in some type of organism and can i) be excreted and collected, ii) remain inside the cell as a soluble product and the cell must be broken open and the product extracted from the broth, or iii) remain as an insoluble product where again the cell must be broken and particulate recovery methods are also required. There are many choices to be made in the production. Many host organisms are used to express the product ... 

The purpose of this subsection is to introduce the reader to the tech-niqiies and methods used to recover materials, conversion products, and energy from solid wastes. Topics to be considered include (I) processing techniques for solid waste, (2) processing techniques for hazardous wastes, (3) materials-recoveiy systems, (4) recovery of biological conversion products, (5) therm processes, and (6) waste-to-energy systems. 

Initially fermentation broth has to be characterised on the viscosity of the fluid. If the presence of the biomass or cells causes trouble, they have to be removed. Tire product is stored inside the cells, the cells must be ruptured and the product must be freed. Intracellular protein can easily be precipitated, settled or filtered. In fact the product in diluted broth may not be economical enough for efficient recovery. Enrichment of the product from the bioreactor effluents for increasing product concentration may reduce the cost of product recovery. There are several economical methods for pure product recovery, such as crystallisation of the product from the concentrated broth or liquid phase. Even small amounts of cellular proteins can be lyophilised or dried from crude solution of biological products such as hormone or enzymes.2,3... 

Purge-and-trap methods have also been used to analyze biological fluids for the presence of trichloroethylene. Breast milk and blood were analyzed for trichloroethylene by purging onto a Tenax gas chromatograph to concentrate the volatiles, followed by thermal desorption and analysis by GC/MS (Antoine et al. 1986 Pellizzari et al. 1982). However, the breast milk analysis was only qualitative, and recoveries appeared to be low for those chemicals analyzed (Pellizzari et al. 1982). Precision (Antoine et al. 1986) and sensitivity (Pellizzari et al. 1982) were comparable to headspace analysis. 

Cold-pressed essential oils from the peel are some of the most important by-products recovered during the processing of Citrus fruits. The presence of limonene in the aqueous discharges, with its antimicrobial activity [1], decreases the effectiveness of the waste treatment system and increases the time necessary for the biological breakdown of the organic matter produced in the peel oil recovery system [2,3]. Additional recovery of essential oils from waste water would increase industry s returns and reduce the pollution problems associated with the disposal of waste water [4,5]. Several methods for reducing the levels of residual essential oils in the aqueous effluent have been developed over the years [6-11]. 

In Chapter 7, approaches for visualization of zones in chromatograms are discussed, including use of nondestructive and destructive dyeing reagents, fluorescence quenching on layers with a fluorescent indicator, and densitometry. In Chapter 8, additional detection methods, such as those used for biologically active and radioactive zones, as well as the recovery of separated, detected zones by scraping and elution techniques are covered. 

An internal standard method gives more reliable results when elaborate sample preparation is required, as in extraction of a drug substance from biological fluids, or extraction of pesticides and herbicides from soil and plant matter. The addition of internal standard (IS) to the sample and standard acts as a marker to give accurate values of the recovery of the desired compound(s). Since the determination of wt% involves the ratio of the detector responses in the two chromatograms, the injection volume is not critical as in an external standard method. 

Subczynski, W. K., J. Widomska, A. Wisniewska, and A. Kusumi. 2007a. Saturation-recovery electron paramagnetic resonance discrimination by oxygen transport (DOT) method for characterizing membrane domains. In Methods in Molecular Biology Lipid Rafts, ed. T. J. McIntosh, Vol. 398, pp. 145-159, Totowa, NJ Humana Press. 

Ibrahim et al. [30] described a fluorimetric method for the determination primaquine and two other aminoquinoline antimalarial drugs using eosin. Powdered tablets or ampule contents containing the equivalent of 50 mg of the drug was extracted with or dissolved in water (100 mL). A 10 mL aliquot was mixed with 10 mL of aqueous ammonia, 1 mL of 0.001% eosin (C.I. acid red 87) in dichloro-ethane, and dichloroethane was added to volume. Primaquine was determined fluorimetrically at 450 nm (excitation at 368 nm). Calibration graphs were rectilinear for 0.1-5 pg/mL of primaquine. Recoveries were quantitative. The method could be readily adapted for determination of the drug in biological fluids. 

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