Styrene degradation

Styrene-degrading bacteria from full-scale and experimental biofilters were exposed to [ HJstyrene, and analysis of fatty acids was used to distinguish the bacterial flora of the two systems (Alexandrino et al. 2001). 

Alexandrine M, C Knief, A Lipski (2001) Stable-isotope based labeling of styrene-degrading microorganisms in biofilters. Appl Environ Microbiol 67 4796-4804. 

Hartmans S, JP Smits, MJ van der Werf, F Volkering, JAM de Bont (1989) Metabolism of styrene oxide and 2-phenylethanol in the styrene-degrading Xanthobacter strain 124X. Appl Environ Microbiol 55 2850-2855. 

Still, a biocatalyst that performs this reaction with an even higher ee was desirable, which led us to investigate styrene degradation in various bacterial soil strains. One of these. Pseudomonas sp. strain VLB 120 was selected for further... 

M. Brebu, M. Azhar Uddin, A. Muto, Y. Sakata, and C. Vasile, The role of temperature program and catalytic system on the quality of acryl-onitrile-butadiene-styrene degradation oil, /. Anal. Appl. Pyrolysis, 63 (l) 43-57, March 2002. 

Figure 1. Styrene degradative pathway in Pseudomonas fluorescens [15].

The above resxUts suggest a degradative pathway of styrene involving an initial epoxidation to styrene oxide, whidi is subsequently isomerized to phenylacetaldehyde and oxidized to phenylacetic acid. The proposed pathway for styrene degradation in strain S5 is shown in Figure 2, and is based on simultaneous adaptation experiments, the transient accumulation of phenylacetic acid and the presence of the required enzymatic activities [18]. After this pathway was published, the present author became aware of a publication by Chapman [19] in which the same pathway is proposed, although no experimental results were presented. 

Cox et al. [7] report that styrene-degrading fungi can also be isolated quite readily, provided that the styrene concentration is kept low. One strain, isolated by van der Werf at pH 4.5 [18], was identified as a black yeast, Exophiala jeanselmei and studied in more detail. Based on the growth-substrate utilization pattern and oxygen-uptake experiments, Cox et al. [7] suggest that styrene oxide, 2-phenylethanol, and phenylacetate could be intermediates of the styrene degradative pathway in this eukaryote. 

Recently, it was shown that the catabolic genes for styrene degradation in P. fluorescens ST are located on the chromosome [24]. A genomic library of the ST strain was constructed and screened in P. putida PaW... 

In the polymerization of styrene, degradation studies on the polymer product suggest that reaction takes place via the phenyl nucleus to a very small extent ... 

The glass-transition temperature depends on the mobility of the chain segments and can therefore be raised by stiffening the chain (see Section 10.5.3). Thus, a-methyl styrene forms a polymer that, in contrast to poly-(styrene), does not deform at lOC C, because of a glass-transition temperature of 170°C. However, since the thermodynamic ceiling temperature for for the polymerization/depolymerization equilibrium is also simultaneously lowered (see Section 16.3), poly(a-methyl styrene) degrades more easily than poly(styrene), so that it is not so easy to work by injection molding. 

Itoh, N., Yoshida, K., and Okada, K. (1996) Isolation and identification of styrene-degrading Corynebactedum strains, and their styrene metahohsm. Biosci. Biotechnol. Biochem., 60, 1826-1830. 

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