Biologically available organic compounds

Biologically available organic contaminants may find their way into the food chain and be toxic, but they are also more easily decomposed and are thus removed from the environment. Slowly decomposed biologically available organic compounds, such as pesticides, may have long lifetimes in soil and thus pose a hazard to animals and humans. Biologically unavailable compounds, such as tars, produce undesirable characteristics in soil, such as water... 

The present chapter includes commercially available organic chemicals. Most of the organo- phosphorus, boron, silicon, alkali metal compounds and metal ion salts are in Chapter 4. Naturally occurring commercially available organic compounds of use in biochemistry, molecular biology and biology are included in Chapter 5. Abbreviations of words and some journal names are listed in Chapter 1, pages 1 and 2. 

Several dozens of aldolases have been identified so far in nature [23,24], and many of these enzymes are commercially available at a scale sufficient for preparative applications. Enzyme catalysis is more attractive for the synthesis and modification of biologically relevant classes of organic compounds that are typically complex, multifunctional, and water soluble. Typical examples are those structurally related to amino acids [5-10] or carbohydrates [25-28], which are difficult to prepare and to handle by conventional methods of chemical synthesis and mandate the laborious manipulation of protective groups. 

The biological availability of contaminating and naturally occurring organic compounds can be estimated by finding their solubility in water. The more soluble the compound, the more available it is for decomposition. While this is true for most organic compounds, there are some that are soluble but also recalcitrant to decomposition. This is the result of complex, sometimes multi-cyclic, structures that inhibit decomposition, such as those of polysaccharides and lignins [2],... 

Wang et al. [42,67,68] have developed innovative biological process and sequencing batch reactors (SBR) specifically for removal of volatile organic compounds (VOCs) and surfactants. Related analytical procedures [57-64,71-91] available for process monitoring and control are available in the literature. 

The most variable aspect of carbon tetrachloride analysis is the procedure used to separate carbon tetrachloride from the medium and prepare a sample suitable for GC analysis. As a volatile organic compound of relatively low water solubility, carbon tetrachloride is easily lost from biological and environmental samples, so appropriate care must be exercised in handling and storing such samples for chemical analysis. Brief summaries of the methods available for extraction and detection of carbon tetrachloride in biological and environmental samples are provided below. 

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