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Liangliang Chen, Ping Sun, Yan Li, Ming Yan, Lin Xu, Kequan Chen, Pingkai Ouyang
The UDP-glucosyltransferase UGT76G1 from Stevia rebaudiana converts stevioside to rebaudioside A via a one-step glycosylation reaction, which increases the amount of sweet-tasting rebaudioside A and decreases the amount of stevioside that has a bitter aftertaste. This enzyme could, therefore, conceivably be used to improve the organoleptic properties of steviol glycosides and offer a cost-effective preparation of high-purity rebaudioside A. Producing soluble enzymes by overexpression is a prerequisite for large-scale biocatalysis...
December 2017: 3 Biotech
Dante A Pertusi, Matthew E Moura, James G Jeffryes, Siddhant Prabhu, Bradley Walters Biggs, Keith E J Tyo
Enzymatic substrate promiscuity is more ubiquitous than previously thought, with significant consequences for understanding metabolism and its application to biocatalysis. This realization has given rise to the need for efficient characterization of enzyme promiscuity. Enzyme promiscuity is currently characterized with a limited number of human-selected compounds that may not be representative of the enzyme's versatility. While testing large numbers of compounds may be impractical, computational approaches can exploit existing data to determine the most informative substrates to test next, thereby more thoroughly exploring an enzyme's versatility...
October 10, 2017: Metabolic Engineering
Clifford S Morrison, William B Armiger, David R Dodds, Jonathan S Dordick, Mattheos A G Koffas
Industrial enzymatic reactions requiring 1,4-NAD(P)H2 to perform redox transformations often require convoluted coupled enzyme regeneration systems to regenerate 1,4-NAD(P)H2 from NAD(P) and recycle the cofactor for as many turnovers as possible. Renewed interest in recycling the cofactor via electrochemical means is motivated by the low cost of performing electrochemical reactions, easy monitoring of the reaction progress, and straightforward product recovery. However, electrochemical cofactor regeneration methods invariably produce adventitious reduced cofactor side products which result in unproductive loss of input NAD(P)...
October 10, 2017: Biotechnology Advances
Hui Song, Wenyu Zhang, Pengju Wang, Huanbo Tan, Wencheng Su, Shuxin Zhao, Peijian Zou
Immobilization of enzymes is important and widely applied in biocatalysis. Streptomyces platensis gene gox, encoding an extracellular L-glutamate oxidase (Gox), was fused to cellulose binding domain (CBDcex) from Cellulomonas fimi and the recombinant protein Gox-CBD was expressed in Escherichia coli. The fusion protein (Gox-CBD) was immobilized onto microcrystalline cellulose. The preparation conditions, binding capacity, properties and stability of the immobilized enzyme were studied. Under the condition of 4 ℃, for 1 hour, the fusion protein Gox-CBD was able to bind microcrystalline cellulose at a ratio of 9...
October 25, 2016: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
Elizabeth S Lewkowicz, Adolfo M Iribarren
Nucleosides constitute an extensive group of natural and chemically modified compounds that display a wide range of structures and activities. Different biocatalysts have been developed for their preparation, but the choice of commercially available enzymes is limited. Therefore, the search of new biocatalysts is particularly attractive. In this sense, microorganisms are a vast source of enzymatic diversity that can be directly used as a whole cell biocatalysts providing a potential cheaper and suitable route for industrial applications...
October 11, 2017: Current Pharmaceutical Design
Blair Ney, Carlo R Carere, Richard Sparling, Thanavit Jirapanjawat, Matthew B Stott, Colin J Jackson, John G Oakeshott, Andrew C Warden, Chris Greening
F420 is a microbial cofactor that mediates a wide range of physiologically important and industrially relevant redox reactions, including in methanogenesis and tetracycline biosynthesis. This deazaflavin comprises a redox-active isoalloxazine headgroup conjugated to a lactyloligoglutamyl tail. Here we studied the catalytic significance of the oligoglutamate chain, which differs in length between bacteria and archaea. We purified short-chain F420 (two glutamates) from a methanogen isolate and long-chain F420 (five to eight glutamates) from a recombinant mycobacterium, confirming their different chain lengths by HPLC and LC/MS analysis...
2017: Frontiers in Microbiology
Wuyuan Zhang, Bastien O Burek, Elena Fernández-Fueyo, Miguel Alcalde, Jonathan Z Bloh, Frank Hollmann
Selective oxyfunctionalisation of inert C-H bonds under mild conditions can be achieved using peroxygenases. This approach, however, is impaired by the poor robustness of these enzymes in the presence of hydrogen peroxide as the stoichiometric oxidant. Here, we demonstrate that inorganic photocatalysts such as gold-titanium dioxide efficiently provide H2O2 from methanol-driven reductive activation of ambient oxygen in suitable amounts to ensure high reactivity and robustness of the enzyme. Using this approach stereoselective hydroxylation of ethyl benzene to (R)-1-phenyl ethanol in high enantioselectivity (>98% ee) and excellent turnover numbers of the biocatalyst (>71...
October 10, 2017: Angewandte Chemie
T M Chen, X M Tian, L Huang, J Xiao, G W Yang
Nanodiamonds (NDs) have recently become a focus of interest from the viewpoints of both science and technology. Their intriguing properties make them suitable as biologically active substrates, in biosensor applications as well as diagnostic and therapeutic biomedical imaging probes. Here, we demonstrate that NDs, as oxidation and reduction catalysts, possess intrinsic enzyme mimetic properties of oxidase, peroxidase and catalase, and these behaviors can be switched by modulating the pH value. NDs not only catalyze the reduction of oxygen (O2) and hydrogen peroxide (H2O2) at acidic pH, but also catalyze the dismutation decomposition of H2O2 to produce O2 at alkaline pH...
October 10, 2017: Nanoscale
Zhixian Li, Huan Xia, Shaomin Li, Jiafeng Pang, Wei Zhu, Yanbin Jiang
By incorporating Cytochrome c (peroxidase, Cyt c) into a skeleton of its corresponding synthetic MOF analogue (peroxidase mimic, CuBDC), approximately 12-fold catalytic efficiency (kcat/KM) enhancement is observed compared to free Cyt c. Meanwhile, the shield endowed by CuBDC prevents encapsulated enzymes from deactivation by trypsin digestion, thermal treatment and long-term storage in vitro. This concept of combining enzymes and their MOF mimics with enhanced enzymatic activity and stability may provide new insights into the design of highly active, stable enzyme-MOF composite catalysts and holds promise for applications in biocatalysis, biosensing and drug delivery systems...
October 19, 2017: Nanoscale
Dietmar Appelhans, Xiaoling Liu, Petr Formanek, Brigitte Voit
Next-generation therapeutic approaches are expected to rely on the engineering of biomimetic cellular systems that can mimic specific cellular functions. Here, we demonstrate a highly effective route to construct structural and functional eukaryotic cell mimics by loading pH-sensitive polymersomes as membrane-associated and free-floating organelle mimics inside the multifunctional cell membrane. Metabolism mimicry has been validated by performing successive enzymatic cascade reactions spatially separated at specific sites of cell mimics in presence and absence of extracellular organelle mimics...
October 2, 2017: Angewandte Chemie
Vijaykumar Karuppiah, Kara E Ranaghan, Nicole G H Leferink, Linus O Johannissen, Muralidharan Shanmugam, Aisling Ní Cheallaigh, Nathan J Bennett, Lewis J Kearsey, Eriko Takano, John M Gardiner, Marc W van der Kamp, Sam Hay, Adrian J Mulholland, David Leys, Nigel S Scrutton
Terpenoids form the largest and stereochemically most diverse class of natural products, and there is considerable interest in producing these by biocatalysis with whole cells or purified enzymes, and by metabolic engineering. The monoterpenes are an important class of terpenes and are industrially important as flavors and fragrances. We report here structures for the recently discovered Streptomyces clavuligerus monoterpene synthases linalool synthase (bLinS) and 1,8-cineole synthase (bCinS), and we show that these are active biocatalysts for monoterpene production using biocatalysis and metabolic engineering platforms...
September 1, 2017: ACS Catalysis
Vishruth Gowda, Jennifer Foulke-Abel, Hillary Agbo, Bennie Bench, Jooyeon Chae, William K Russell, Coran M H Watanabe
Lipofuscins are toxic autofluorescent byproducts of the visual cycle. The accumulation of lipofuscins such as cycloretinal in the retina is attributed to playing a role in the progression of age-related macular degeneration (AMD). Intriguingly, the milk protein β-lactoglobulin (BLG) can promote the cyclodimerization of all-trans retinal to cycloretinal both in vitro and in vivo. Here, site-directed mutagenesis of BLG as well as mass spectrometric analysis with substrate analogs demonstrate that lysine residues play a key role in catalysis...
September 29, 2017: Biochemistry
Tiansheng Gan, Xiangjun Gong
It was known that bacteria adhere to surfaces and form sessile colonies called biofilms. Biofilms show potential applications for biodegradation and biocatalysis, whilst they also cause healthy and environmental problems. In particular, they lead to human infections and biofouling problems in industry. Physical properties of biofilms reflect the architecture and mechanical stability of biofilms that are highly related to their resistance to environmental challenges and their survival. In this article, we reviewed the physical properties involved in the development of biofilms and the related characterization techniques...
September 25, 2017: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
Yaping He, Jianbin Zheng, Bini Wang, Hongjiang Ren
Controllable preparation of nanopores to promote the performance of electrochemical biosensing interfaces has become one of the researching frontiers in biosensing. A double biocatalysis signal amplification of glucose biosensor for the study of electrochemical behaviors of glucose oxidase (GOx) was proposed by using horseradish peroxidase biosynthesized porous graphene (PGR) as the platform for the biocatalytic deposition of gold nanoparticles (AuNPs). The biosensor showed a linear range from 0.25 to 27.5 μM with a detection limit of 0...
September 27, 2017: Materials
Alexandra T P Carvalho, Daniel F A R Dourado, Timofey Skvortsov, Miguel de Abreu, Lyndsey J Ferguson, Derek J Quinn, Thomas S Moody, Meilan Huang
Phenylacetone monooxygenase (PAMO) is the most stable and thermo-tolerant member of the Baeyer-Villiger monooxygenase family, and therefore it is an ideal candidate for the synthesis of industrially relevant compounds. However, its limited substrate scope has largely limited its industrial applications. In the present work, we provide, for the first time, the catalytic mechanism of PAMO for the native substrate phenylacetone as well as for a linear non-native substrate 2-octanone, using molecular dynamics simulations, quantum mechanics and quantum mechanics/molecular mechanics calculations...
October 11, 2017: Physical Chemistry Chemical Physics: PCCP
Pengchao Wang, Xinwei Yang, Baixue Lin, Jianzhong Huang, Yong Tao
The efficiency of biocatalysis is often affected by an insufficient supply and regeneration of cofactors and redox equivalents. To alleviate this shortcoming, a cofactor self-sufficient system was developed for enhanced production of 2-phenylethanol (2-PE) in E. coli. A "bridge" between the amino acid and its corresponding alcohol was designed in the system using glutamate dehydrogenase. By coupling glutamate dehydrogenase with transaminase and alcohol dehydrogenase, the cosubstrate (2-oxoglutarate) and redox equivalents (NAD(P)H) were regenerated simultaneously, so that no external cofactor or redox source was required...
September 22, 2017: Metabolic Engineering
Fernando López-Gallego, Eriene Jackson, Lorena Betancor
Industrial biocatalysis is playing a key role in the development of the global bio-economy that must change our current productive model to pair the socio-economical development with the preservation of our already harmed planet. The exploitation of isolated multi-enzyme systems and the discovery of novel biocatalytic activities are leading us to manufacture chemicals that were inaccessible through biological routes in the early past. These endeavors have been grouped in the concept of Systems biocatalysis...
September 26, 2017: Chemistry: a European Journal
Susanna Seppälä, St Elmo Wilken, Doriv Knop, Kevin V Solomon, Michelle A O'Malley
A wealth of fungal enzymes has been identified from nature, which continue to drive strain engineering and bioprocessing for a range of industries. However, while a number of clades have been investigated, the vast majority of the fungal kingdom remains unexplored for industrial applications. Here, we discuss selected classes of fungal enzymes that are currently in biotechnological use, and explore more basal, non-conventional fungi and their underexploited biomass-degrading mechanisms as promising agents in the transition towards a bio-based society...
September 21, 2017: Metabolic Engineering
Christophe Duplais, Yannick Estevez
Bioengineering the genes of plants and microbes is becoming a very competitive strategy in synthesis to produce pharmacologically relevant plant natural products and their unnatural analogues. During the last 20 years several plant genes have been identified, cloned and expressed successfully unlocking de novo production of plant metabolites such as morphine, strictosidine, artemisinin, taxol® and resveratrol. Future development for accelerating the discovery of gene candidates relies on innovative computational methods combined with transcriptomics and metabolomics analysis to make plant genome mining more feasible...
September 20, 2017: Chembiochem: a European Journal of Chemical Biology
Meng Wang, Biqiang Chen, Yunming Fang, Tianwei Tan
Cofactors are involved in numerous intracellular reactions and critically influence redox balance and cellular metabolism. Cofactor engineering can support and promote the biocatalysis process, even help driving thermodynamically unfavorable reactions forwards. To achieve efficient production of chemicals and biofuels, cofactor engineering strategies such as altering cofactor supply or modifying reactants' cofactor preference have been developed to maintain redox balance. This review focuses primarily on the effects of cofactor engineering on carbon and energy metabolism...
September 20, 2017: Biotechnology Advances
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