Production of l-tryptophan by enantioselective hydrolysis of d,l-tryptophanamide using a newly isolated bacterium

2013 ◽  
Vol 67 (10) ◽  
Author(s):  
Jian-Miao Xu ◽  
Ben Chen ◽  
Yuan-Shan Wang ◽  
Yu-Guo Zheng
Keyword(s):  
Enantiomeric Excess ◽  
Fold Increase ◽  
Fermentation Medium ◽  
High Yield ◽  
Enantioselective Hydrolysis ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Enantiomeric Ratio ◽  
Physiological Tests ◽  
Hydrolysis Of

AbstractBacterial strain ZJB-09211 capable of amidase production has recently been isolated from soil samples. The strain is able to asymmetrically hydrolyze l-tryptophanamide from d,l-tryptophanamide to produce l-tryptophan in high yield and with excellent stereoselectivity (enantiomeric excess > 99.9 %, and enantiomeric ratio > 200). Strain ZJB-09211 has been identified as Flavobacterium aquatile based on the cell morphology analysis, physiological tests, and the 16S rDNA sequence analysis. Optimization of the fermentation medium led to an about six-fold increase in the amidase activity of strain ZJB-09211, which reached 501.5 U L−1. Substrate specifity and stereoselectivity investigations revealed that amidase of F. aquatile possessed a broad substrate spectrum and high enantioselectivity.

Isolation of an esterase-producing Trichosporon brassicae and its catalytic performance in kinetic resolution of ketoprofen

2001 ◽  
Vol 47 (12) ◽  
pp. 1101-1106 ◽  
Author(s):  
Duan Shen ◽  
Jian-He Xu ◽  
Peng-Fei Gong ◽  
Hui-Yuan Wu ◽  
You-Yan Liu
Keyword(s):  
Ethyl Ester ◽  
Sole Carbon Source ◽  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Catalytic Performance ◽  
Soil Samples ◽  
Enantioselective Hydrolysis ◽  
Resting Cells ◽  
Enantiomeric Ratio ◽  
Hydrolysis Of

A yeast strain CGMCC 0574, identified as Trichosporon brassicae, was selected from 92 strains for its high (S) selectivity in the hydrolysis of ketoprofen ethyl ester. The effective strains of the microorganisms were isolated from soil samples with the ester as the sole carbon source. The ethyl ester proved to be the best substrate for resolution of ketoprofen among several ketoprofen esters examined. The resting cells of CGMCC 0574 could catalyze the hydrolysis of ketoprofen ethyl ester with an enantiomeric ratio of 44.9, giving (S)-ketoprofen an enantiomeric excess of 91.5% at 42% conversion.Key words: ketoprofen, biocatalytic resolution, enantioselective hydrolysis, microbial esterase, Trichosporon brassicae.

SCREENING OF STRAINS FOR ENANTIOSELECTIVE HYDROLYSIS OF RACEMIC MENTHYL BENZOATE TO PRODUCT L-MENTHOL

2013 ◽  
pp. 63-69
Author(s):  
Thi Minh Thu Ngo ◽  
Gao-Wei Zheng ◽  
Jian-He Xu
Keyword(s):  
Catalytic Properties ◽  
Hydrolytic Activity ◽  
Soil Samples ◽  
Enantioselective Hydrolysis ◽  
16S Rdna Sequence ◽  
Optimum Ph ◽  
Acinetobacter Sp ◽  
Hydrolysis Of ◽  
Dry Cell ◽  
Biocatalytic Process

Background: Because of pleasant flavor and aroma as well as cooling-anesthetic effect, menthol and mint oils are widely used in the flavor industry and biocatalytic processes for production of l-menthol are more interested nowadays. Herein, we attempted to develop a biocatalytic process for production of l-menthol through enantioselective hydrolysis of dl-menthyl benzoate using a strain newly isolated from soil. Methods: From soil samples, we were isolated one strain exhibited the best hydrolytic activity and excellent enantioselectivity as compared to others. So, it was selected as the best enzyme producer and subsequently identified as Acinetobacter sp. based on the 99% similarity of its 16S rDNA sequence, and named Acinetobacter sp. ECU2040. The fermentation process was studied and the fermentation gave about 130 g wet cell, which was equivalent to 18 g dry cell. The catalytic properties of Acinetobacter sp. ECU2040 were also studied. The results showed that the optimum pH and temperature of reaction were 7.5 and 37ºC, respectively. Results and conclusion: The strain Acinetobacter sp. ECU2040 strain exhibited the production of l-menthol ability with the best hydrolytic activity and excellent enantioselectivity. Key words: l-menthol, enantioselective, isolated strain

scholarly journals Cloning and Characterization of a Novel Esterase from Rhodococcus sp. for Highly Enantioselective Synthesis of a Chiral Cilastatin Precursor

2014 ◽  
Vol 80 (23) ◽  
pp. 7348-7355 ◽  
Author(s):  
Yan Zhang ◽  
Jiang Pan ◽  
Zheng-Jiao Luan ◽  
Guo-Chao Xu ◽  
Sunghoon Park ◽  
...  
Keyword(s):  
Enantiomeric Excess ◽  
Green Manufacturing ◽  
Enantioselective Hydrolysis ◽  
Content Type ◽  
Chiral Building Block ◽  
Chain Acyl ◽  
Novel Esterase ◽  
Optically Pure ◽  
Hydrolysis Of

ABSTRACTA novel nonheme chloroperoxidase (RhEst1), with promiscuous esterase activity for enantioselective hydrolysis of ethyl (S)-2,2-dimethylcyclopropanecarboxylate, was identified from a shotgun library ofRhodococcussp. strain ECU1013.RhEst1 was overexpressed inEscherichia coliBL21(DE3), purified to homogeneity, and functionally characterized. Fingerprinting analysis revealed thatRhEst1 preferspara-nitrophenyl (pNP) esters of short-chain acyl groups.pNP esters with a cyclic acyl moiety, especially that with a cyclobutanyl group, were also substrates forRhEst1. TheKmvalues for methyl 2,2-dimethylcyclopropanecarboxylate (DmCpCm) and ethyl 2,2-dimethylcyclopropane carboxylate (DmCpCe) were 0.25 and 0.43 mM, respectively.RhEst1 could serve as an efficient hydrolase for the bioproduction of optically pure (S)-2,2-dimethyl cyclopropane carboxylic acid (DmCpCa), which is an important chiral building block for cilastatin. As much as 0.5 M DmCpCe was enantioselectively hydrolyzed into (S)-DmCpCa, with a molar yield of 47.8% and an enantiomeric excess (ee) of 97.5%, indicating an extremely high enantioselectivity (E= 240) of this novel and unique biocatalyst for green manufacturing of highly valuable chiral chemicals.

scholarly journals Lipase-Catalyzed Kinetic Resolution of Dimethyl and Dibutyl 1-Butyryloxy-1-Carboxymethylphosphonates

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 956
Author(s):  
Paulina Majewska
Keyword(s):  
Burkholderia Cepacia ◽  
Kinetic Resolution ◽  
Wide Spectrum ◽  
Candida Rugosa ◽  
Enantiomeric Excess ◽  
Optically Active ◽  
Enantiomeric Ratio ◽  
Catalyzed Reactions ◽  
Hydrolysis Of ◽  
Different Sources

The main objective of this study is the enantioselective synthesis of carboxyhydroxyphosphonates by lipase-catalyzed reactions. For this purpose, racemic dimethyl and dibutyl 1-butyryloxy-1-carboxymethylphosphonates were synthesized and hydrolyzed, using a wide spectrum of commercially available lipases from different sources (e.g., fungi and bacteria). The best hydrolysis results of dimethyl 1-butyryloxy-1-carboxymethylphosphonate were obtained with the use of lipases from Candida rugosa, Candida antarctica, and Aspergillus niger, leading to optically active dimethyl 1-carboxy-1-hydroxymethylphosphonate (58%–98% enantiomeric excess) with high enantiomeric ratio (reaching up to 126). However, in the case of hydrolysis of dibutyl 1-butyryloxy-1-carboxymethylphosphonate, the best results were obtained by lipases from Burkholderia cepacia and Termomyces lanuginosus, leading to optically active dibutyl 1-carboxy-1-hydroxymethylphosphonate (66%–68% enantiomeric excess) with moderate enantiomeric ratio (reaching up to 8.6). The absolute configuration of the products after biotransformation was also determined. In most cases, lipases hydrolyzed (R) enantiomers of both compounds.

Degradation of nicosulfuron by a novel isolated bacterial strain Klebsiella sp. Y1: condition optimization, kinetics and degradation pathway

2016 ◽  
Vol 73 (12) ◽  
pp. 2896-2903 ◽  
Author(s):  
Lin Wang ◽  
Xiaolin Zhang ◽  
Yongmei Li
Keyword(s):  
Response Surface Methodology ◽  
Bacterial Strain ◽  
Degradation Pathway ◽  
Optimal Conditions ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Condition Optimization ◽  
Metabolic Degradation ◽  
Hydrolysis Of ◽  
Optimal Ph

Abstract A novel bacterial strain Klebsiella sp. Y1 was isolated from the soil of a constructed wetland, and it was identified based on the 16S rDNA sequence analysis. The co-metabolic degradation of nicosulfuron with glucose by Klebsiella sp. Y1 was investigated. The response surface methodology analysis indicated that the optimal pH and temperature were 7.0 and 35 °C, respectively, for the degradation of nicosulfuron. Under the optimal conditions, the degradation of nicosulfuron fitted Haldane kinetics model well. The removal of nicosulfuron was triggered by the acidification of glucose, which accelerated the hydrolysis of nicosulfuron. Then, the C–N bond of the sulfonylurea bridge was attacked and cleaved. Finally, the detected intermediate 2-amino-4,6-dimethoxypyrimidine was further biodegraded.

scholarly journals Application of Lecitase® Ultra-Catalyzed Hydrolysis to the Kinetic Resolution of (E)-4-phenylbut-3-en-2-yl Esters

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 423 ◽  
Author(s):  
Aleksandra Leśniarek ◽  
Anna Chojnacka ◽  
Witold Gładkowski
Keyword(s):  
Kinetic Resolution ◽  
Enantiomeric Excess ◽  
Optical Purity ◽  
Enantioselective Hydrolysis ◽  
Hydrolysis Of ◽  
Allyl Esters

The possibility of using Lecitase® Ultra as a novel alternative biocatalyst for the kinetic resolution of model racemic allyl esters of (E)-4-phenylbut-3-en-3-ol: Acetate (4a) and propionate (4b) through their enantioselective hydrolysis was investigated. Reaction afforded (+)-(R)-alcohol (3) and unreacted (−)-(S)-ester (4a or 4b). Hydrolysis of propionate 4b proceeded with higher enantioselectivity than acetate 4a. (R)-Alcohol (3) with highest enantiomeric excess (93–99%) was obtained at 20–30 °C by hydrolysis of propionate 4b, while the highest optical purity of unreacted substrate was observed for (S)-acetate 4a (ee = 34–56%). The highest enantioselectivity was found for the hydrolysis of propionate 4b catalyzed at 30 °C (E = 38). Reaction carried out at 40 °C significantly lowered enantiomeric excess of produced alcohol 3 and enantioselectivity in resolution. Lecitase® Ultra catalyzed the enantioselective hydrolysis of allyl esters 4a,b according to Kazlauskas’ rule to produce (R)-alcohol 3 and can find application as a novel biocatalyst in the processes of kinetic resolution of racemic allyl esters.

Enantioselectivity of carbonic anhydrase catalyzed hydrolysis of mandelic methyl esters

1990 ◽  
Vol 68 (2) ◽  
pp. 314-316 ◽  
Author(s):  
Robert Chênevert ◽  
Martin Létourneau
Keyword(s):  
Carbonic Anhydrase ◽  
Methyl Esters ◽  
Enantiomeric Excess ◽  
Enantioselective Hydrolysis ◽  
Hydrolysis Of Esters ◽  
Hydrolysis Of

We report the first enantioselective hydrolysis of esters catalyzed by carbonic anhydrase. We found that mandelic methyl esters are good substrates for carbonic anhydrase. The R enantiomers are better substrates and enantiomeric excess values are moderate (40–51%). Keywords: carbonic anhydrase, mandelic esters, enantioselectivity, hydrolysis.

Papaya shoot tip associated endophytic bacteria isolated from in vitro cultures and host–endophyte interaction in vitro and in vivo

2007 ◽  
Vol 53 (3) ◽  
pp. 380-390 ◽  
Author(s):  
Pious Thomas ◽  
Sima Kumari ◽  
Ganiga K. Swarna ◽  
T.K.S. Gowda
Keyword(s):  
Culture Medium ◽  
Carica Papaya ◽  
In Vitro Cultures ◽  
Dependent Manner ◽  
16S Rdna Sequence ◽  
16S Rdna Sequence Analysis ◽  
Single Organism ◽  
Dose Dependent

Fourteen distinct bacterial clones were isolated from surface-sterilized shoot tips (~1 cm) of papaya (Carica papaya L. ‘Surya’) planted on Murashige and Skoog (MS)-based papaya culture medium (23/50 nos.) during the 2–4 week period following in vitro culturing. These isolates were ascribed to six Gram-negative genera, namely Pantoea ( P. ananatis ), Enterobacter ( E. cloacae ), Brevundimonas ( B. aurantiaca ), Sphingomonas , Methylobacterium ( M. rhodesianum ), and Agrobacterium ( A. tumefaciens ) or two Gram-positive genera, Microbacterium ( M. esteraromaticum ) and Bacillus ( B. benzoevorans ) based on 16S rDNA sequence analysis. Pantoea ananatis was the most frequently isolated organism (70% of the cultures) followed by B. benzoevorans (13%), while others were isolated from single stocks. Bacteria-harboring in vitro cultures often showed a single organism. Pantoea, Enterobacter, and Agrobacterium spp. grew actively on MS-based normal papaya medium, while Microbacterium, Brevundimonas, Bacillus, Sphingomonas, and Methylobacterium spp. failed to grow in the absence of host tissue. Supplying MS medium with tissue extract enhanced the growth of all the organisms in a dose-dependent manner, indicating reliance of the endophyte on its host. Inoculation of papaya seeds with the endophytes (20 h at OD550 = 0.5) led to delayed germination or slow seedling growth initially. However, the inhibition was overcome by 3 months and the seedlings inoculated with Pantoea, Microbacterium, or Sphingomonas spp. displayed significantly better root and shoot growths.

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