Production of secondary

This is as far as we want to take our discussion of the development of deep cultures for the production of penicillin in this chapter. It is an aspect of the production of secondary metabolites, such as penicillin, more appropriately dealt with in the technology texts in the BIOTOL series. 

Fig. 1-6. Roentgen s production of secondary x-rays. The secondary x-rays from zinc are most efficiently absorbed by the emulsion and give the maximum darkening.

Roentgen, definition of the, 248 Roentgen, W. C., discovery and investigation of x-rays by, 2, 9-12, 43 Nobel Prize awarded to, 2 production of secondary x-rays by, 12 x-ray absorption studies by, 11 x-ray papers of, 2... 

In classical organic chemistry, nltrosamlnes were considered only as the reaction products of secondary amines with an acidified solution of a nitrite salt or ester. Today, it is recognized that nitrosamines can be produced from primary, secondary, and tertiary amines, and nltrosamides from secondary amides. Douglass et al. (34) have published a good review of nitrosamine formation. For the purposes of this presentation, it will suffice to say that amine and amide precursors for nitrosation reactions to form N-nitroso compounds are indeed ubiquitous in our food supply, environment, and par-... 

I. PRODUCTION OF ANTIBIOTICS. The production of secondary metabolites with antimicrobial properties has long been recognized as an important factor in disease suppression (see Chap. 7). Metabolites with biocontrol properties have been isolated from a large number of rhizosphere microorganisms, including the fluorescent pseudomonads (Table 2). Further discussion is not given here since this is the subject of recent reviews (122,123). 

Table 7.6 Material fuel equivalent (MFE) for production of secondary metals.

Among all the metals listed in Table 7.6, the MFE for the production of secondary tin is as much as 91% of the MFE for the production of primary tin. This unusual situation arises from the fact that tinned steel contains only 0.2-0.3% tin, and the processing of this source involves dissolution of the tin in a caustic solution, followed by an energy-intensive electrowinning operation to obtain metallic tin. An advantage is that the detinned steel scrap is suitable for steel manufacture. 

The production of secondary zinc requires only 20-25% of the energy required for primary zinc production. Only one-fourth of the total zinc produced is the secondary metal. The reason for such limited recycling is that the major application of zinc is in castings rather than in parts. 

AOPP has been used in many studies to examine the role of PAL in the synthesis of secondary aromatic compounds. The results summarized in Table I indicate that levels of AOPP that have little or no effect on growth can strongly affect production of secondary aromatic products. Other studies have shown rapid cessation of isoflavone synthesis in Cicer ariethinum by 0.3 mM AOPP (61). 

Streptomyces strains are Gram positive [54], they have good secretion capacities and extensive fermentation knowledge has been accumulated. Mostly, they were used for the production of secondary metabolites with potent biological activities, such as antibiotics, immunosuppressors or pesticides. Constitutive [55] and inducible [56] expression is possible. Up to 40% of the total soluble cellular protein was reported in the case of inducible expression. 

Nielsen, J. (1998) The role of metabolic engineering in the production of secondary metabolites. Current Opinion in Microbiology, 1, 330—336. 

From the very successful developments of the alcohol dehydrogenase technology for production of secondary alcohols and enzymatic reductive amination of keto-acids for production of amino acids, it is expected that we will also soon see applications for other enzymatic redox chemistries for example, reduction of unsaturated carbonyl compounds with... 

These dynamic strategies also play important roles in the chemical defense of benthic organisms. Only in recent years have marine scientists started to apply methods that allow these defensive strategies to be monitored. This opens the field for the identification of signals that play a role in species-species interactions in the marine environment and for the elucidation of hormones responsible for regulating the production of secondary metabolites. 

Upon sonication in halocarbon solvents, metal carbonyls undergo facile halogenations (186). The rates of halogenation are solvent dependent, but independent of choice of metal carbonyl or its concentration, and represent the products of secondary reactions occurring from the sonolytic decomposition of the halocarbon solvent, as shown in Eqs. (16)-(20). Alkanes and other halogen atom traps suppress the halogenation of the metal carbonyls. 

It can be seen that primary and secondary R02 radicals disproportionate with the participation of the a-C—H bond. This explains why the substitution of D in the a-position for H retards the recombination of R02 [/tn//tD =1.9 for ethylbenzene, h/ d = 2.1 for styrene, and h/ d=1-37 for diphenylmethane [179]). Because of this, R02 radicals of unsaturated compounds with a double bond in the a-position to the peroxyl free valence disproportionate more rapidly than structurally analogous aliphatic peroxyl radicals (at 300 K, 2kt = 2x 107 and 3.8 x 106 L mol-1 s-1 for R02 radicals of cyclohexene and cyclohexane, respectively [180]). Among the products of secondary peroxyl radicals disproportionation, carbonyl compound and alcohol were found in a ratio of 1 1 at room temperature (in experiments with ethylbenzene [181], tetralin [103], and cyclohexane [182-184],... 

Hydrogen peroxide was identified as the product of secondary peroxyl radical disproportionation [187-192], It cannot be explained by the concerted mechanism of tetroxide decomposition. 

Scheme A. This scheme is typical of the hydrocarbons, which are oxidized with the production of secondary hydroperoxides (nonbranched paraffins, cycloparaffins, alkylaro-matic hydrocarbons of the PhCH2R type) [3,146]. Hydroperoxide initiates free radicals by the reaction with RH and is decomposed by reactions with peroxyl and alkoxyl radicals. The rate of initiation by the reaction of hydrocarbon with dioxygen is negligible. Chains are terminated by the reaction of two peroxyl radicals. The rates of chain initiation by the reactions of hydroperoxide with other products are very low (for simplicity). The rate of hydroperoxide accumulation during hydrocarbon oxidation should be equal to ...

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