Pseudomonas fluorescens, conversion

Specific information about the optimum conditions for the synthesis and the activity of the enzyme has been reported for Pseudomonas fluorescens screening of various micro-organisms resulted in the selection of a P. fluorescens strain with an initial rate of conversion of 3 g P h 1 in an imoptimised state. The following conclusions could be made concerning the production of L-phenylalanine by P. fluorescens ... 

Figure 8.12 Conversion of benzaldehyde into enantiomerically pure (S)-mandelic acid by the sequential addition of HCN catalyzed by the (.S )-selective oxynitrilase from Manihot esculenta (MeHnL), and subsequent hydrolysis of the resultant (5)-mandelonitrile by the nitrilase from Pseudomonas fluorescens ECB 191 (PfNLase)...

Kunz DA, Nagappan O, Silva-Avalos J, et al. 1992. Utilization of cyanide as a nitrogenous substrate by Pseudomonas fluorescens NCIMB 11764 Evidence for multiple pathways of metabolic conversion. Appl Environ Microbiol 58(6) 2022-2029. 

Hoft reported about the kinetic resolution of THPO (16b) by acylation catalyzed by different lipases (equation 12) °. Using lipases from Pseudomonas fluorescens, only low ee values were obtained even at high conversions of the hydroperoxide (best result after 96 hours with lipase PS conversion of 83% and ee of 37%). Better results were achieved by the same authors using pancreatin as a catalyst. With this lipase an ee of 96% could be obtained but only at high conversions (85%), so that the enantiomerically enriched (5 )-16b was isolated in poor yields (<20%). Unfortunately, this procedure was limited to secondary hydroperoxides. With tertiary 1-methyl-1-phenylpropyl hydroperoxide (17a) or 1-cyclohexyl-1-phenylethyl hydroperoxide (17b) no reaction was observed. The kinetic resolution of racemic hydroperoxides can also be achieved by chloroperoxidase (CPO) or Coprinus peroxidase (CiP) catalyzed enantioselective sulfoxidation of prochiral sulfides 22 with a racemic mixmre of chiral hydroperoxides. In 1992, Wong and coworkers and later Hoft and coworkers in 1995 ° investigated the CPO-catalyzed sulfoxidation with several chiral racemic hydroperoxides while the CiP-catalyzed kinetic resolution of phenylethyl hydroperoxide 16a was reported by Adam and coworkers (equation 13). The results are summarized in Table 4. 

Lipases from Pseudomonas sp. [Amano PS and Pseudomonas fluorescens lipase (PFL)] are useful. Provided that the conversion is high enough, the remaining (R)-2-methylalkanols R-2 can be obtained almost enantiomerically pure. The (S)-... 

Williams employed complexes of Al, Rh, or Ir in combination with PFL (Pseudomonas fluorescens lipase) for the DKR of 1-phenylethanol. The best results were obtained using Rh2(OAc)4 as the catalyst for the racemization which gave 60% conversion of the alcohol to 1-phenylethyl acetate in 98% (Scheme 5.22) [43]. 

The Pseudomonas fluorescens KdgA was shown to accept several polar-sub-stituted aldehydes, albeit at rates much lower ( < 1%) than the phosphorylated natural substrate 12 (Table 3) [137]. Simple aliphatic or aromatic aldehydes were not converted. Synthetic utility and high stereoselectivity with unnatural substrates were demonstrated by conversion of both the D-configurated glycer-aldehyde (d-15) and lactaldehyde (d-16) to form the respective (4S)-configurated adducts 17 and 18 at the mmol scale. 

Typical kinetic resolutions of the arylpropionic acids are those of flurbiprofen 16 and ketoprofen 18 with a cell-free extract of Pseudomonas fluorescens. Note the special ester (trifluoroethyl) selected for maximum efficiency and how successful that is perfect ee in the hydrolysed products at close to 50% conversion.8 The unreacted esters 15 and 17 can of course be racemised by enolisation and added to the next resolution. 

Figure 2. A) Genetic organization of the pKAl catabolic plasmid. Genes of the upper naphthalene regulatory system encode for proteins that mediate the conversion of naphthalene to salicylate. Salicylate is then further degraded to TCA cycle intermediates. B) In Pseudomonas fluorescens HK44, genes within the lower pathway were replaced with genes of the lux cassette to produce a bioluminescent bioreporter sensitive to naphthalene and salicylate.

The correct catabolic pattern of histidine was established first in bacterial preparations and for this reason will be discussed first. Cell-free extracts of Pseudomonas fluorescens were obtained which catalyze the quantitative conversion of L-histidine to L-glutamic acid, formic acid, and 2 moles of NH3, as required by equation 14. Proof of the formation of L-glutamate was obtained by isolating the crystalline hydrochloride from the incubation mixture and establishing its identity. ... 

Methyl-5-benzyl oxycarbonyl-1,3- dioxan- 2-one Pseudomonas fluorescens lipase M = 6,100, DP = 1.6 using GPC against a polystyrene standard. Reaction time 72 b, conversion 97% at 80 °C [49]... 

The growing importance of 15 has lead to the development of alternative methodologies to obtain this compound enantiomerically pure. One of the most noteworthy uses the lipase from Pseudomonas fluorescens to effect a selective esterification of racemic 1-ferrocenylethanol 12a. At 50% conversion the unreacted alcohol (5)-(-l-)-12a was isolated with an enantiomeric excess of 92% and the acetate 16 had an enantiomeric purity of 96%. Simply stirring this acetate with aqueous dimethylamine resulted in formation of (/ )-(+)-lV,iV-dimethyl-a-ferrocenylethylamine with [a]o -I- 12.8, corresponding to an optical pxuity of 91%. ... 

The Williams group reported the DKR of 1-phenylethanol as the first metalloenzy-matic DKR [9]. This DKR employed Pseudomonas fluorescens lipase (PPL) as the resolution enzyme, a rhodium complex as the racemization catalyst, and vinyl acetate as the acyl donor in cyclohexane, but the reaction required a stoichiometric amoxmt of acetophenone for hydrogen transfer and stopped at 60% conversion (Scheme 5.6). 

Baum, S., Williamson, D.S., Sewell, T., and Stolz, A. (2012). Conversion of sterically demanding a, a-disubstituted phenylacetonitriles by the arylacetonitrUase from Pseudomonas fluorescens EBC191. Applied and Environmental Microbiology, 78,48-57. 

Racemization of the remnant substrate in a DKR process can be performed either spontaneously or by the employment of a chemo- or biocatalyst, which must be compatible with the reaction conditions used for the KR reaction. In the case of sec-alcohols, most of successful DKRs have been carried out by the use of ruthenium complex catalysts, soluble in the organic reaction media, which promote racemization through redox processes. The first examples describe the resolution of 1-phenylethanol (rac-1) by the combination of a rhodium catalyst (Rh2(OAc) ) with Pseudomonas fluorescens lipase [22], although more effective results were afforded by Backvall and coworkers [23], who developed the DKR of the same substrate and derivatives catalyzed by Candida antarctica lipase (CALB) and a ruthenium complex (Shvo s catalyst, 2 (Figure 14.2)), affording excellent conversions and enantiomeric excess (ee) values [24]. 

Naumova, R. R, S. Y. Selivanovskaya, and I. E. Cherepneva. 1988. Conversion of 2,4,6-trinitrotoluene under conditions of oxygen and nitrate respiration of Pseudomonas fluorescens. Appl. Biochem. Microbiol. 24 409-413. 

The conversion of toluene to the cw-dihydrodiol has been examined using inunobilized P. putida UV4, and a dramatic increase in production observed under defined conditions of aeration in a fluidized-bed reactor [48]. The naphthalene dioxygenase enzyme from Pseudomonas fluorescens has been expressed in E. coli, and the resulting biocatalyst used for the conversion of a series of substituted naphthalenes to the diols shown in Fig. 29 [49], while Pseudomonas testosteroni ACS converts 2-naphthoic acid to the diol 40 shown in Fig. 30 [50]. Substituted biphenyls are also substrates for TDO oxidation (Fig. 31) using E. coli JM109 expressing this enzyme [51]. 

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