Transformation microorganism

For those pesticides that are cometabolized, ie, not utilized as a growth substrate, the assumption of first-order kinetics is appropriate. The more accurate kinetic expression is actually pseudo-first-order kinetics, where the rate is dependent on both the pesticide concentration and the numbers of pesticide-degrading microorganisms. However, because of the difficulties in enumerating pesticide-transforming microorganisms, first-order rate constants, or half-hves, are typically reported. Based on kinetic constants, it is possible to rank the relative persistence of pesticides. Pesticides with half-hves of <10 days are considered to be relatively nonpersistent pesticides with half-hves of >100 days are considered to be relatively persistent. 

A BDS method using a transformed microorganism containing a recombinant DNA molecule of Rhodococcus origin. This transformed microorganism expresses a BDS-active biocatalyst. (Use in BDS of the biocatalyst protected in Refs. [37-39])... 

Application of molecular biology to obtain transformed microorganisms. cells, or animals having new and/or enhanced capabilities to generate bioproducts. 

Insoluble, inactive inclusion bodies are frequently formed upon recombinant protein production in transformed microorganisms. These inclusion bodies, which... 

R Okamoto, T Fukumoto, K Imafuku, T Kubo, K Kiyoshima, A Takamatsu, T Takeuchi. Screening for 16-membered macrolide-transforming microorganisms. J Ferment Technol 57 519-528, 1979. 

Wink, M. (1989) Genes of secondary metabolism differential expression in plants and in vitro cultures and functional expression in genetically transformed microorganisms, in Primary and Secondary Metabolism of Plant Cell Cultures (ed. WG.W Kurz). Springer-Verlag, Berlin, pp. 239-51. 

B. Lawlis, W. Rastetter, and R. Snedecor, Recombinant process for preparing Lramino adds, recombinant expression vectors and transformed microorganisms for use in the process, European Patent Application No. 84305532.8, 1985. 

Propylene glycol (1,2-propanediol) is a commodity chemical. U.S. 6,087,140 (to Wisconsin Alumni Research Foundation) describes a process for fermentation of sugars to propylene glycol using transformed microorganisms. Estimate the maximum price that could be charged for the microorganisms. 

The rate and extent of pesticide metaboHsm can vary dramatically, depending on chemical stmcture, the number of specific pesticide-degrading microorganisms present and their affinity for the pesticide, and environmental parameters. The extent of metaboHsm can vary from relatively minor transformations which do not significantly alter the chemical or toxicological properties of the pesticide, to mineralisation, ie, degradation to CO2, H2O, NH" 4, Cf, etc. The rate of metaboHsm can vary from extremely slow (half-life of years) to rapid (half-life of days). 

Hydrodechlorination has long been recogni2ed as an important chemical transformation. However, the en2ymatic hydrodechlorination of atra2ine (3) by soil microorganisms has also been demonstrated (eq. 15) (21). 

Persistence of pesticides in the environment is controlled by retention, degradation, and transport processes and their interaction. Retention refers to the abihty of the soil to bind a pesticide, preventing its movement either within or outside of the soil matrix. Retention primarily refers to the sorption process, but also includes absorption into the soil matrix and soil organisms, both plants and microorganisms. In contrast to degradation that decreases the absolute amount of the pesticide in the environment, sorption processes do not affect the total amount of pesticide present in the soil but can decrease the amount available for transformation or transport. 

Biotin is produced by a multistep pathway in a variety of fungi, bacteria, and plants (50—56). The estabUshed pathway (50,56) in E. coli is shown in Figure 6. However, Htde is known about the initial steps that lead to pimelyl-Co A or of the mechanism of the transformation of desthiobiotin to biotin. Pimelic acid is beheved to be the natural precursor of biotin for some microorganisms (51). 

Since the microbiological degradation is a rather specialized reaction, no experimental details are given in this chapter. The success of such a reaction depends not only on the proper choice of substrate and proper duplication of the fermentation medium, but also on obtaining the proper strain of microorganism reported to perform a particular transformation. 

Bioprocess plants are an essential part of food, fine chemical and pharmaceutical industries. Use of microorganisms to transform biological materials for production of fermented foods, cheese and chemicals has its antiquity. Bioprocesses have been developed for an enoimous range of commercial products, as listed in Table 1.1. Most of the products originate from relatively cheap raw materials. Production of industrial alcohols and organic solvents is mostly originated from cheap feed stocks. The more expensive and special bioprocesses are in the production of antibiotics, monoclonal antibodies and vaccines. Industrial enzymes and living cells such as baker s yeast and brewer s yeast are also commercial products obtained from bioprocess plants. 

F. H. Stodola, Chemical Transformations by Microorganisms, John Wiley Sons, New York 1958. 

In freshwater systems, the only biodegradation product detected was 4-nitrophenol, which was rapidly utilized and transformed to undetectable metabolites by the microorganisms present. In seawater, the main initial product was methyl aminoparathion, formed by reduction of the nitro group (Badawy and El-Dib 1984). Studies in raw river water showed that 4-nitrophenol and dimethyl thiophosphoric acid are the main degradation products (Eichelberger and Lichtenberg 1971). 

Lewis DL, Holm HW. 1981. Rates of transformation of methyl parathion and diethyl phthalate by aufwuchs microorganisms. Appl Environ Microbiol 42 698-703. 

Endosulfan is released to the environment mainly as the result of its use as an insecticide. Significant contamination is limited to areas where endosulfan is manufactured, formulated, applied, or disposed of. The compound partitions to the atmosphere and to soils and sediments. Endosulfan can be transported over long distances in the atmosphere, but the compound is relatively immobile in soils. It is transformed by hydrolysis to the diol and by microorganisms to a number of different metabolites. It is bioconcentrated only to low levels and does not biomagnify in terrestrial or aquatic food chains. 

---