Degradation by strain

Figure 1. Time courese of PEA degradation by strain lU-3. The strain was cultured at 30 °C. Growth ( O), PEA ( ), water-soluble TOC (a), ethylene glycol (A) and pH ( ) are shown.

Figure 14. Proposed pathway of Propachlor degradation by strains DAKS and MAB2 of Moraxella and Xanthobacter, respectively [234].

Figure 3.115 Epothilones A and B degradation by strains of S. cellulosum. (a) epothilone A/B monooxygenase (b) epothilone A/B esterase (c) epothilone E/F esterase (d) epothilone A/B monooxygenase.

Poly(butylene succinate-co-bntylene adipate) (PBSA)-degrading bacteriirm was isolated from soil and identified as Bacillus pumilus [80]. It also degraded poly (butylene succinate) (PBS) and poly( -caprolactone) (PCL). On the other hand, poly (butylene adipate tereph-thalate) and poly(lactic acid) were minimally degraded by strain. The NMR spectra of degradation products from PBSA indicated that the adipate imits were more rapidfy degraded than 1,4-butanediol and succinate units. It was proposed to be one of the reasons why Bacillus pumilus degraded PBSA than PBS. 

Speculation about the stability of Ceo centered on the extent to which the aromaticity associated with its 20 benzene rings is degraded by their non planarity and the accompanying angle strain It is now clear that Ceo is a relatively reactive substance reacting with many substances toward which ben zene itself is inert Many of these reactions are char acterized by addition to buckminsterfullerene converting sp hybridized carbons to sp hybridized ones and reducing the overall strain... 

RABOT s, GUERIN c, NUGON-BAUDON L and SZYLIT o (1995) Glucosinolate degradation by bacterial strains isolated from a human intestinal microflora , Proc. 9th International Rapeseed Congress, 1 212-14. 

Pure cultures growing anaerobically with catechol and sulfate were isolated,and the carboxylation of catechol was proposed to be the initial reaction of anaerobic catechol degradation by Desulfobacterium sp. strain Cat2. Zhang and Young" proposed that the initial key reaction for anaerobic degradation of naphthalene and phenanthrene was also carboxylation. 

The a-isomer of hexachlorocyclohexane exists in two enantiomeric forms, and both are degraded by Sphingomonas paucimobilis strain B90A by dehydrochlorination to 1,3,4, 6-tetrachlorocyclohexa-l,4-diene that is spontaneously degraded to 1,2,4-trichlorophenol. 

Nitrotoluene is degraded by a strain of Mycobacterium sp. via the corresponding 4-amino-3-hydroxytoluene (Spiess et al. 1998) this is dimerized abiotically to form a dihydrophenox-azinone, and after extradiol cleavage to 5-methylpyridine -2-carboxylate (Figure 2.2d). 

This can be degraded by several mycobacteria including Mycobacterium aurum strain MOl (Combourieu et al. 1998), Mycobacterium strain RPl (Poupin et al. 1998), and Mycobacterium chelonae (Swain et al. 1991). The reaction is initiated by a cytochrome P450 monooxygenase that is also active against pyrrolidine and piperidine (Poupin et al. 1998). 

The oxidation by strains of Pseudomonas putida of the methyl group in arenes containing a hydroxyl group in the para position is, however, carried out by a different mechanism. The initial step is dehydrogenation to a quinone methide followed by hydration (hydroxylation) to the benzyl alcohol (Hopper 1976) (Figure 3.7). The reaction with 4-ethylphenol is partially stereospecific (Mclntire et al. 1984), and the enzymes that catalyze the first two steps are flavocytochromes (Mclntire et al. 1985). The role of formal hydroxylation in the degradation of azaarenes is discussed in the section on oxidoreductases (hydroxylases). 

Strains may be able to regulate the pathway of degradation of toluene to the availability of oxygen aerobic degradation by dioxygenation and under denitrifying conditions in the absence of oxygen by the benzylsuccinate pathway. 

There may be several reasons why an analog substrate cannot be metabolized by an organism. This is well illustrated by 4-ethylbenzoate that could not be used by strains that degraded 3- and 4-methylbenzoate (Ramos et al. 1987). There were two reasons ... 

Dejonghe W, E Berteloot, J Goris, N Boon, K Crul, S Maertens, M Hofte, P de Vos, W Verstraete, EM Top (2003) Synergistic degradation of linuron by a bacterial consortium and isolation of a single linuron-degrading Variovorax strain. Appl Environ Microbiol 69 1532-1542. 

Folsom BR, PJ Chapman, PH Pritchard (1990) Phenol and trichloroethylene degradation by Pseudomonas cepacia G4 kinetics and interactions between substrates. Acinetobacter sp. strain A-CBl. Appl Environ Microbiol 56 1279-1285. 

Gilbert ES, DE Crowley (1997) Plant compounds that induce polychlorinated biphenyl degradation by Arthro-bacter sp. strain BIB. Appl Environ Microbiol 63 1933-1938. 

Shinoda Y, Y Sakai, H Uenishi, Y Uchihashi, A Hiraishi, H Yukawa, H Yurimoto, N Kato (2004) Aerobic and anaerobic toluene degradation by a newly isolated denitrifying bacterium, Thauera sp. strain DNT-1. Appl Environ Microbiol 70 1385-1392. 

There are two pathways for the degradation of nitriles (a) direct formation of carboxylic acids by the activity of a nitrilase, for example, in Bacillus sp. strain OxB-1 and P. syringae B728a (b) hydration to amides followed by hydrolysis, for example, in P. chlororaphis (Oinuma et al. 2003). The monomer acrylonitrile occurs in wastewater from the production of polyacrylonitrile (PAN), and is hydrolyzed by bacteria to acrylate by the combined activity of a nitrilase (hydratase) and an amidase. Acrylate is then degraded by hydration to either lactate or P-hydroxypropionate. The nitrilase or amidase is also capable of hydrolyzing the nitrile group in a number of other nitriles (Robertson et al. 2004) including PAN (Tauber et al. 2000). 

Hage JC, S Hartmans (1999) Monooxygenation-mediated 1,2-dichloroethane degradation by Pseudomonas sp. strain DCAl. Appl Environ Microbiol 65 2466-2470. 

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