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Jin-Song Gong, Qiang Zhang, Bing-Chen Gu, Ting-Ting Dong, Heng Li, Hui Li, Zhen-Ming Lu, Jin-Song Shi, Zheng-Hong Xu
The constitutively expression system for P. putida nitrilase was firstly constructed to improve the nicotinic acid production and reduce the production costs. High density culture strategy was employed to enhance the biomass and nitrilase production of recombinant strain. The total nitrilase activity reached up to 654 U·mL-1 without the induction. 541 g·L-1 nicotinic acid was accumulated via fed batch mode of substrate feeding through 290 min of conversion.
March 30, 2018: Bioresource Technology
Zhe Xu, Ting Cai, Neng Xiong, Shu-Ping Zou, Ya-Ping Xue, Yu-Guo Zheng
Nitrilases can hydrolyze nitriles to corresponding carboxylic acids in one single step, which have great potential as valuable biocatalysts for chemical synthesis. However, the poor thermostability of the nitrilases restrict their applications in industry. In this work, error-prone PCR and site-directed mutagenesis were utilized to improve the thermostability of nitrilases. Several mutants (AcN-Q339K, AcN-Q343K, AcN-T201F, AcN-T201W, AcN-T201L, AcN-T201I) were obtained with dramatically improved thermostability...
June 2018: Enzyme and Microbial Technology
Ludmila Martínková, Vladimír Křen
The aim of this study is to summarize the current progress in the design of biocatalytic processes applicable for the production of optically pure mandelic acids and their analogues. These compounds are used as building blocks for pharmaceutical chemistry and as chiral resolving agents. Their enzymatic syntheses mainly employed nitrile hydrolysis with nitrilases, ester hydrolysis, ammonolysis or esterification with lipases or esterases, and ketone reduction or alcohol oxidation with dehydrogenases. Each of these methods will be characterized in terms of its product concentrations, enantioselectivities, and the types of catalysts used...
March 10, 2018: Applied Microbiology and Biotechnology
Renu Singh, Anirban Banerjee, Praveen Kaul, Brajesh Barse, U C Banerjee
In the original version of our paper entitled "Release of an enantioselective nitrilase from Alcaligenes faecalis MTCC 126: a comparative study" (2005) 27:415-424, some references to already published articles were inadvertently left out.
February 24, 2018: Bioprocess and Biosystems Engineering
Tek Chand Bhalla, Vijay Kumar, Virender Kumar, Neerja Thakur, Savitri
Nitrile metabolizing enzymes, i.e., aldoxime dehydratase, hydroxynitrile lyase, nitrilase, nitrile hydratase, and amidase, are the key catalysts in carbon nitrogen triple bond anabolism and catabolism. Over the past several years, these enzymes have drawn considerable attention as prominent biocatalysts in academia and industries because of their wide applications. Research on various aspects of these biocatalysts, i.e., sources, screening, function, purification, molecular cloning, structure, and mechanisms, has been conducted, and bioprocesses at various scales have been designed for the synthesis of myriads of useful compounds...
January 30, 2018: Applied Biochemistry and Biotechnology
Nikhil Sharma, Ruchi Verma, Savitri, Tek Chand Bhalla
ProCos (Protein Composition Server, script version), one of the machine learning techniques, was used to classify nitrilases as aliphatic and aromatic nitrilases. Some important feature vectors were used to train the algorithm, which included pseudo-amino acid composition (PAAC) and five-factor solution score (5FSS). This clearly differentiated into two groups of nitrilases, i.e., aliphatic and aromatic, achieving maximum sensitivity of 100.00%, specificity of 90.00%, accuracy of 95.00% and Mathew Correlation Coefficient (MCC) of about 0...
January 2018: 3 Biotech
Michael J Benedik, B Trevor Sewell
No abstract text is available yet for this article.
December 30, 2017: Journal of General and Applied Microbiology
Heidi Fisk, Yun Xu, Chloe Westley, Nicholas J Turner, Jason Micklefield, Royston Goodacre
Process analytical technologies (PAT) are used within industry to give real-time measurements of critical quality parameters, ultimately improving the quality by design (QbD) of the final product and reducing manufacturing costs. Spectroscopic and spectrophotometric methods are readily employed within PAT due to their ease of use, compatibility toward a range of sample types, robustness, and multiplexing capabilities. We have developed a UV resonance Raman (UVRR) spectroscopy approach to quantify industrially relevant biotransformations accurately, focusing on nitrile metabolizing enzymes: nitrile hydratase (NHase) and amidase versus nitrilase activity...
November 8, 2017: Analytical Chemistry
Xin-Hong Zhang, Zhi-Qiang Liu, Ya-Ping Xue, Yuan-Shan Wang, Bo Yang, Yu-Guo Zheng
Recombinant Escherichia coli cells harboring nitrilase from Alcaligenes faecalis were immobilized using tris(hydroxymethyl)phosphine (THP) as the coupling agent. The optimal pH and temperature of the THP-immobilized cells were determined at pH 8.0 and 55 °C. The half-lives of THP-immobilized cells measured at 35, 40, and 50 °C were 1800, 965, and 163 h, respectively. The concentration of R-mandelic acid (R-MA) reached 358 mM after merely 1-h conversion by the immobilized cells with 500 mM R,S-mandelonitrile (R,S-MN), affording the highest productivity of 1307 g L(-1) day(-1) and the space-time productivity of 143...
September 22, 2017: Applied Biochemistry and Biotechnology
Guangyuan Lu, Yingzhi Xu, Kai Zhang, Yong Xiong, He Li, Lei Cui, Xianping Wang, Jizhong Lou, Yujia Zhai, Fei Sun, Xuejun C Zhang
In Gram-negative bacteria, lipid modification of proteins is catalysed in a three-step pathway. Apolipoprotein N-acyl transferase (Lnt) catalyses the third step in this pathway, whereby it transfers an acyl chain from a phospholipid to the amine group of the N-terminal cysteine residue of the apolipoprotein. Here, we report the 2.6-Å crystal structure of Escherichia coli Lnt. This enzyme contains an exo-membrane nitrilase domain fused to a transmembrane (TM) domain. The TM domain of Lnt contains eight TM helices which form a membrane-embedded cavity with a lateral opening and a periplasmic exit...
July 4, 2017: Nature Communications
Ting-Ting Dong, Jin-Song Gong, Bing-Chen Gu, Qiang Zhang, Heng Li, Zhen-Ming Lu, Mao-Lin Lu, Jin-Song Shi, Zheng-Hong Xu
The objective of the study was to enhance the substrate tolerance of Pseudomonas putida nitrilase via atmospheric and room temperature plasma (ARTP) and cell immobilization. The mutant library was constructed by ARTP and rapidly screened by an OPA-TCA microscale reaction. A mutant strain of mut-D3 was obtained and its optimum substrate concentration was improved to 150mM from 100mM. It could accumulate 189g/L nicotinic acid (NA) from 3-cyanopyridine (3-CP), which was increased by 42% compared with that of wild type (WT)...
November 2017: Bioresource Technology
Chong Han, Scott Savage, Mohammad Al-Sayah, Herbert Yajima, Travis Remarchuk, Reinhard Reents, Beat Wirz, Hans Iding, Stephan Bachmann, Serena M Fantasia, Michelangelo Scalone, André Hell, Pirmin Hidber, Francis Gosselin
A highly efficient asymmetric synthesis of the Akt kinase inhibitor ipatasertib (1) is reported. The bicyclic pyrimidine 2 starting material was prepared via a nitrilase biocatalytic resolution, halogen-metal exchange/anionic cyclization, and a highly diastereoselective biocatalytic ketone reduction as key steps. The route also features a halide activated, Ru-catalyzed asymmetric hydrogenation of a vinylogous carbamic acid to produce α-aryl-β-amino acid 3 in high yield and enantioselectivity. The API was assembled in a convergent manner through a late-stage amidation/deprotection/monohydrochloride salt formation sequence...
August 31, 2017: Organic Letters
Sandra Pierre, Gareth W Griffith, Russell M Morphew, Luis A J Mur, Ian M Scott
Nine geographically diverse Moniliophthora perniciosa (witches' broom disease pathogen) isolates were cultured in vitro. They included six C-biotypes differing in virulence on cacao (Theobroma cacao), two S-biotypes (solanaceous hosts), and an L-biotype (liana hosts). Mycelial growth rates and morphologies differed considerably, but no characters were observed to correlate with virulence or biotype. In plant inoculations using basidiospores, one C-biotype caused symptoms on tomato (an S-biotype host), adding to evidence of limited host adaptation in these biotypes...
September 2017: Fungal Biology
Shengfei Jin, Vu T Nguyen, Hang T Dang, Dat P Nguyen, Hadi D Arman, Oleg V Larionov
We report herein a photoinduced carboborative ring contraction of monounsaturated six-membered carbocycles and heterocycles. The reaction produces substituted five-membered ring systems stereoselectively and on preparative scales. The products feature multiple stereocenters, including contiguous quaternary carbons. We show that the reaction can serve as a synthetic platform for ring system alteration of natural products. The reaction can also be used in natural product synthesis. A concise total synthesis of artalbic acid has been enabled by a sequence of photoinduced carboborative ring contraction, Rauhut-Currier reaction, and nitrilase-catalyzed hydrolysis...
August 23, 2017: Journal of the American Chemical Society
Haiyang Fan, Lifeng Chen, Huihui Sun, Hualei Wang, Qinghai Liu, Yuhong Ren, Dongzhi Wei
OBJECTIVE: To investigate the biodegradation of nitriles via the nitrilase-mediated pathway. RESULTS: A novel nitrilase, BGC4, was identified from proteobacteria Paraburkholderia graminis CD41M and its potential for use in biodegradation of toxic nitriles in industrial effluents was studied. BGC4 was overexpressed in Escherichia coli BL21 (DE3), the recombinant protein was purified and its enzymatic properties analysed. Maximum activity of BGC4 nitrilase was at 30 °C and pH 7...
November 2017: Biotechnology Letters
Ma Ángeles Cabrera, Jenny M Blamey
Nitriles are important chemical building blocks for the synthesis of intermediates in fine chemical and pharmaceutical industries. Here, we report a new highly thermostable nitrilase from an Antarctic Pyrococcus sp. MC-FB, a hyperthermophilic archaeon. A gene that encoded a nitrilase was identified and subsequently cloned and overexpressed in Escherichia coli. The recombinant nitrilase, named NitMC-FB, is active as a homodimer (60 kDa) with an optimal temperature and pH of 90 °C and 7.0, respectively. NitMC-FB hydrolyzes preferentially aromatic nitriles, being the first aromatic nitrilase from an archaeon described so far...
September 2017: Extremophiles: Life Under Extreme Conditions
Anirban Banerjee, Praveen Kaul, U C Banerjee
No abstract text is available yet for this article.
July 8, 2017: Applied Microbiology and Biotechnology
Xiao-Zhang Yu, Yu-Juan Lin, Chun-Jiao Lu, Xue-Hong Zhang
Involvement of genes (CYS-A1, CYS-C1 and NIT4) encoded with cysteine synthase, β-cyanoalanine synthase, nitrilase and cyanide metabolisms are evident in Arabidopsis. In the present study, identifications of CYS-A1, CYS-C1 and NIT4, predictions of conserved motifs, and constructions of phylogenetic relationships, based on their amino acid sequences in rice, were conducted. In order to elucidate the transcriptional responses of these cyanide-degrading genes, two candidate homologues were selected for each gene to test their expression changes upon exposure to exogenous KCN in rice seedlings using RT-PCR...
September 2017: Ecotoxicology
Vinod K Nigam, Tesnim Arfi, Vishal Kumar, Pratyoosh Shukla
Nitrilases are commercial biocatalysts used for the synthesis of plastics, paints, fibers in the chemical industries, pharmaceutical drugs and herbicides for agricultural uses. Nitrilase hydrolyses the nitriles and dinitriles to their corresponding carboxylic acids and ammonia. They have a broad range of substrate specificities as well as enantio-, regio- and chemo-selective properties which make them useful for biotransformation of nitriles to important compounds because of which they are considered as 'Green Catalysts'...
June 2017: Indian Journal of Microbiology
Haiyang Fan, Lifeng Chen, Huihui Sun, Hualei Wang, Yuhong Ren, Dongzhi Wei
A novel aliphatic nitrilase, REH16, was found in Ralstonia eutropha H16 and overexpressed in Escherichia coli BL21(DE3), and its enzymatic properties were studied. The temperature and pH optima were 37 °C and 6.6, respectively, and the best thermostability of the nitrilase was observed at 25 °C, which preserved 95% of activity after 120 h of incubation. REH16 has a broad hydrolytic activity toward aliphatic and heterocyclic nitriles and showed high tolerance of 3-cyanopyridine; this enzyme could hydrolyze as high as 100 mM 3-cyanopyridine completely...
August 2017: Bioprocess and Biosystems Engineering
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