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Shan Chen, Jonatan C Campillo-Brocal, Per Berglund, Maria Svedendahl Humble
The amine transaminase from Vibrio fluvialis (Vf-ATA) is an attractive enzyme with applications within Biocatalysis for the preparation of chiral amines. Various catalytic properties of Vf-ATA have been investigated, but a biophysical characterization of its stability has been lacking. Today, the industrial application of Vf-ATA is limited by its low operational stability. In order to enhance the knowledge regarding the structural stability of ATAs, general characterizations of different ATAs are required. In this work, the stability of Vf-ATA was explored...
June 12, 2018: Journal of Biotechnology
Qingcai Zhao, Marion Ansorge-Schumacher, Rainer Haag, Changzhu Wu
The design and construction of polymeric compartmentalized structures in water have been intensively explored for controllable catalysis, but the challenge still remains to set up catalytic compartments in organic media. Herein, we designed a simple block copolymer, PCL-b-PEG-b-PCL, to construct a stable and multi-compartmentalized emulsion in an organic solvent by hand-shaking. This gentle emulsion preparation allowed a successful encapsulation of vulnerable biocatalysts such as benzaldehyde lyase (BAL) and alcohol dehydrogenase (ADH)...
June 12, 2018: Chemistry: a European Journal
Kyle F Biegasiewicz, Simon J Cooper, Megan A Emmanuel, David C Miller, Todd K Hyster
Strategies that provide enzymes with the ability to catalyse non-natural reactions are of considerable synthetic value. Photoredox catalysis has proved adept at expanding the synthetic repertoire of existing catalytic platforms, yet, in the realm of biocatalysis it has primarily been used for cofactor regeneration. Here we show that photoredox catalysts can be used to enable new catalytic function in nicotinamide-dependent enzymes. Under visible-light irradiation, xanthene-based photocatalysts enable a double-bond reductase to catalyse an enantioselective deacetoxylation...
June 11, 2018: Nature Chemistry
Maria Bawn, Fabiana Subrizi, Gary J Lye, Tom D Sheppard, Helen C Hailes, John M Ward
The use of biocatalysis for the synthesis of high value added chemical building blocks derived from biomass is becoming an increasingly important application for future sustainable technologies. The synthesis of a higher value chemical from l-arabinose, the predominant monosaccharide obtained from sugar beet pulp, is demonstrated here via a transketolase and transaminase coupled reaction. Thermostable transketolases derived from Deinococcus geothermalis and Deinococcus radiodurans catalysed the synthesis of l-gluco-heptulose from l-arabinose and β-hydroxypyruvate at elevated temperatures with high conversions...
September 2018: Enzyme and Microbial Technology
Shaohua Li, Aihua Zhang, Kelly Zatopek, Saba Parvez, Andrew Fenn Gardner, Ivan Correa, Christopher J Noren, Ming-Qun Xu
Covalent immobilization of enzymes on solid supports provides an alternative approach to homogeneous biocatalysis by adding benefits of simple enzyme removal, improved stability, and adaptability to automation and high-throughput applications. Nevertheless, immobilized (IM) enzymes generally suffer from reduced activities compared to their soluble counterparts. The nature and hydrophobicity of the supporting material surface can introduce enzyme conformational change, spatial confinement, and limited substrate accessibility, all of which will result in the immobilized enzyme activity loss...
June 4, 2018: Bioconjugate Chemistry
Shao-Bin Fu, Xu Feng, Qing-Feng Meng, Qing Cai, Di-An Sun
Biotransformation of Echinocystic acid (EA,1) using G. roseum CGMCC 3.3657 has been investigated, which leads to the isolation and identification of two novel Echinocystic acid derivatives, 4, 16α-dihydroxy-3,4-seco-olean-12-en-3,28-dioic acid (2) and 16α-hydroxy, A-homo-3α-oxa-olean-12-en-3-one-28-oic acid (3). Their structures have been elucidated by analysis of spectroscopic data. This biocatalysis could serve as an efficient tool complementary to classical chemical methods for the transformation of EA...
May 29, 2018: Natural Product Research
Zhen Xie, Jianbo Guo, Caicai Lu, Yuanyuan Song, Yajuan Xing, Qingxiong Yang, Yi Han, Haibo Li
In this research, the nitrate reduction rate increased 2-3 fold in the presence of five different porphyrin compounds (0.25 mM), among which hemin expressed the best accelerating effectiveness. Therefore, hemin was used to explore the catalytic characteristics and mechanisms during denitrification. The relationship between hemin concentrations (Chemin ) and nitrate reduction rates (k) could be best described by the equation k = 8.7463 + 0.44528ln (Chemin -0.00993) (R2  = 0.9908). Furthermore, the activation energy decreased 87% compared to the hemin-free system...
May 18, 2018: Bioresource Technology
Victoria McCarl, Mark V Somerville, Mai-Anh Ly, Rebecca Henry, Elissa F Liew, Neil L Wilson, Andrew J Holmes, Nicholas V Coleman
Alkene monooxygenases (MOs) are soluble di-iron-containing enzymes found in bacteria that grow on alkenes. Here we report improved heterologous expression systems for the propene MO (PmoABCD) and ethene MO (EtnABCD) from Mycobacterium chubuense strain NBB4. Strong functional expression of PmoABCD and EtnABCD was achieved in Mycobacterium smegmatis mc2 -155, yielding epoxidation activites (62 and 27 nmol/min/mg protein, respectively) higher than any reported to date for heterologous expression of a di-iron MO system...
May 25, 2018: Applied and Environmental Microbiology
Ningzi Guan, Hyun-Dong Shin, Lingfeng Long, Parastoo Azadi, Rachel Chen
Microbial catalysis has recently emerged as one of the most promising approaches in oligosaccharide synthesis. However, despite significant progresses, microbial synthesis still requires much improvement in efficiency and in reduction of process complexity. Additionally, given the stunning diversity and many varied applications of glycans, broadening the range of glycans accessible via microbial synthesis is of paramount importance. Major challenges in microbial synthesis include catabolite repression and high cellular energy requirement...
May 24, 2018: Glycobiology
Fabián Garzón-Posse, Liliana Becerra-Figueroa, José Hernández-Arias, Diego Gamba-Sánchez
Currently, the power and usefulness of biocatalysis in organic synthesis is undeniable, mainly due to the very high enantiomeric excess reached using enzymes, in an attempt to emulate natural processes. However, the use of isolated enzymes has some significant drawbacks, the most important of which is cost. The use of whole cells has emerged as a useful strategy with several advantages over isolated enzymes; for this reason, modern research in this field is increasing, and various reports have been published recently...
May 25, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Grace L Huang, Jason E Gosschalk, Ye Seong Kim, Rachel R Ogorzalek Loo, Robert T Clubb
Microbes engineered to display heterologous proteins could be useful biotechnological tools for protein engineering, lignocellulose degradation, biocatalysis, bioremediation, and biosensing. Bacillus subtilis is a promising host to display proteins, as this model Gram-positive bacterium is genetically tractable and already used industrially to produce enzymes. To gain insight into the factors that affect displayed protein stability and copy number, we systematically compared the ability of different protease-deficient B...
May 23, 2018: Applied Microbiology and Biotechnology
Louis Lancaster, Walaa Abdallah, Scott Banta, Ian Wheeldon
Protein engineering provides a means to alter protein structure leading to new functions. Much work has focused on the engineering of enzyme active sites to enhance catalytic activity, however there is an increasing trend towards engineering other aspects of biocatalysts as these efforts can also lead to useful improvements. This tutorial discusses recent advances in engineering an enzyme's local chemical and physical environment, with the goal of enhancing enzyme reaction kinetics, substrate selectivity, and activity in harsh conditions (e...
May 25, 2018: Chemical Society Reviews
Matthias Engleder, Harald Pichler
Water addition to carbon-carbon double bonds provides access to value-added products from inexpensive organic feedstock. This interesting but relatively little-studied reaction is catalysed by hydratases in a highly regio- and enantiospecific fashion with excellent atom economy. Considering that asymmetric hydration of (non-activated) carbon-carbon double bonds is virtually impossible with current organic chemistry, enzymatic hydration reactions are highly attractive for industrial applications. Hydratases have been known for several decades but their biocatalytic potential has only been explored over the past 15 years...
May 21, 2018: Applied Microbiology and Biotechnology
Abaynesh Yihdego Gebreyohannes, Madhav Dharmjeet, Tom Swusten, Matthias Mertens, Joran Verspreet, Thierry Verbiest, Christophe M Courtin, Ivo F J Vankelecom
This work aimed at investigating simultaneous hydrolysis of cellulose and in-situ foulant degradation in a cellulose fed superparamagnetic biocatalytic membrane reactor (BMRSP ). In this reactor, a dynamic layer of superparamagnetic bionanocomposites with immobilized cellulolytic enzymes were reversibly immobilized on superparamagnetic polymeric membrane using an external magnetic field. The formation of a dynamic layer of bionanocomposites on the membrane helped to prevent direct membrane-foulant interaction...
May 2, 2018: Bioresource Technology
Saadet Alpdağtaş, Sevil Yücel, Handan Açelya Kapkaç, Siqing Liu, Barış Binay
OBJECTIVES: To identify a robust NADP+ dependent formate dehydrogenase from Lactobacillus buchneri NRRL B-30929 (LbFDH) with unique biochemical properties. RESULTS: A new NADP+ dependent formate dehydrogenase gene (fdh) was cloned from genomic DNA of L. buchneri NRRL B-30929. The recombinant construct was expressed in Escherichia coli BL21(DE3) with 6 × histidine at the C-terminus and the purified protein obtained as a single band of approx. 44 kDa on SDS-PAGE and 90 kDa on native-PAGE...
May 18, 2018: Biotechnology Letters
Ruijie Zhang, Xiangcen Liu, Yushi Wang, Yuchang Han, Junsong Sun, Jiping Shi, Baoguo Zhang
BACKGROUND: 3-Ketosteroid-Δ1-dehydrogenase (KstD) is a key enzyme in the metabolic pathway for chemical modifications of steroid hormones. Only a few KstDs have thus far been characterized biochemically and applied for the production of steroidal pharmaceutical intermediates. Three KstDs, KstD1, KstD2, and KstD3, were identified in Mycobacterium neoaurum DSM 1381, and they shared up to 99, 85 and 97% amino acid identity with previously reported KstDs, respectively. In this paper, KstDs from M...
May 18, 2018: Microbial Cell Factories
Robson Carlos Alnoch, Adriano Alves Stefanello, Viviane de Paula Martini, Jeferson Luiz Richter, Cesar Mateo, Emanuel Maltempi de Souza, David Alexander Mitchell, Marcelo Muller-Santos, Nadia Krieger
Genes encoding lipase LipBC (lipA) and foldase LifBC (lipB) were identified in the genome of Burkholderia contaminans LTEB11. Analysis of the predicted amino acid sequence of lipA showed its high identity with lipases from Pseudomonas luteola (91%), Burkholderia cepacia (96%) and Burkholderia lata (97%), and classified LipBC lipase in the lipase subfamily I.2. The genes lipA and lipB were amplified and cloned into expression vectors pET28a(+) and pT7-7, respectively. His-tagged LipBC and native LifBC were co-expressed in Escherichia coli and purified...
May 15, 2018: International Journal of Biological Macromolecules
Abraham J Waldman, Emily P Balskus
The molecular architectures and potent bioactivities of diazo-containing natural products have attracted the interest of synthetic and biological chemists. Despite this attention, the biosynthetic enzymes involved in diazo group construction have not been identified. Here, we show the ATP-dependent enzyme CreM installs the diazo group in cremeomycin via late-stage N-N bond formation using nitrite. This finding should inspire efforts to use diazo-forming enzymes in biocatalysis and synthetic biology and enable genome-based discovery of new diazo-containing metabolites...
May 17, 2018: Journal of Organic Chemistry
Roger A Sheldon, Dean Brady
In the period 1985 to 1995 applications of biocatalysis, driven by the need for more sustainable manufacture of chemicals and catalytic, (enantio)selective methods for the synthesis of pharmaceutical intermediates, largely involved the available hydrolases. This was followed, in the next two decades, by revolutionary developments in protein engineering and directed evolution for the optimisation of enzyme function and performance that totally changed the biocatalysis landscape. In the same period, metabolic engineering and synthetic biology revolutionised the use of whole cell biocatalysis in the synthesis of commodity chemicals by fermentation...
May 17, 2018: Chemical Communications: Chem Comm
Nadine Zumbrägel, Christian Merten, Stefan M Huber, Harald Gröger
The 3-thiazolidine ring represents an important structural motif in life sciences molecules. However, up to now reduction of 3-thiazolines as an attractive approach failed by means of nearly all chemical reduction technologies for imines. Thus, the development of an efficient general and enantioselective synthetic technology giving access to a range of such heterocycles remained a challenge. Here we present a method enabling the reduction of 3-thiazolines with high conversion and high to excellent enantioselectivity (at least 96% and up to 99% enantiomeric excess)...
May 16, 2018: Nature Communications
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