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Enzymatic hydrolysis

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https://www.readbyqxmd.com/read/29054871/engineering-the-enantioselectivity-and-thermostability-of-a-%C3%AE-lactamase-from-microbacterium-hydrocarbonoxydans-for-the-kinetic-resolution-of-vince-lactam
#1
Shuaihua Gao, Shaozhou Zhu, Rong Huang, Hongxia Li, Hao Wang, Guojun Zheng
To produce promising biocatalysts, natural enzymes often need to be engineered to increase their catalytic performance. In this study, the enantioselectivity and thermostability of a (+)-γ-lactamase from Microbacterium hydrocarbonoxydans as the catalyst in the kinetic resolution of Vince lactam were improved. Enantiomerically pure (-)-Vince lactam is the key synthon in the synthesis of antiviral drugs such as carbovir and abacavir, which are used to fight against human HIV and hepatitis B viruses. The work was initialized by using the combinatorial active-site saturation test strategy to engineer the enantioselectivity of the enzyme...
October 20, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29054065/investigating-desorption-during-ethanol-elution-to-improve-the-quality-and-antioxidant-activity-of-xylo-oligosaccharides-from-corn-stalk
#2
Jie Zhang, Yue-Hai Wang, Quan-Yuan Wei, Xiao-Jia Du, Yong-Shui Qu
As the most representative of lignocellulosic materials, corn stalk (CS) will be a great candidate to produce xylo-oligosaccharides (XOS). Owing to the high impurity content of the XOS produced by directly enzymatic hydrolysis of xylan extracted from CS, subsequent refining steps are essential. The present study was aimed to investigate desorption during ethanol elution to improve the quality and antioxidant activity of XOS from CS. The desorption was systematically investigated after optimizing the elution conditions...
October 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29054055/an-integrated-green-process-subcritical-water-enzymatic-hydrolysis-and-fermentation-for-biohydrogen-production-from-coconut-husk
#3
Maktum Muharja, Fitri Junianti, Dian Ranggina, Tantular Nurtono, Arief Widjaja
The objective of this work is to develop an integrated green process of subcritical water (SCW), enzymatic hydrolysis and fermentation of coconut husk (CCH) to biohydrogen. The maximum sugar yield was obtained at mild severity factor. This was confirmed by the degradation of hemicellulose, cellulose and lignin. The tendency of the changing of sugar yield as a result of increasing severity factor was opposite to the tendency of pH change. It was found that CO2 gave a different tendency of severity factor compared to N2 as the pressurizing gas...
October 9, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29053869/enzymatic-hydrolysis-of-fumonisins-in-the-gastrointestinal-tract-of-broiler-chickens
#4
B Grenier, H E Schwartz-Zimmermann, C Gruber-Dorninger, I Dohnal, M Aleschko, G Schatzmayr, W D Moll, T J Applegate
Fumonisins (FB) are among the most frequently detected mycotoxins in feedstuffs and finished feed, and recent data suggest that the functions of the gastrointestinal tract (GIT) in poultry species might be compromised at doses ranging from 10 to 20 mg/kg, close to field incidences and below the US and EU guidelines. Strategies are therefore necessary to reduce the exposure of poultry to FB. In the present study, we assessed the efficacy of fumonisin esterase FumD (EC 3.1.1.87, commercial name FUMzyme®) to cleave the tricarballylic acid side chains of FB, leading to the formation of non-toxic hydrolyzed fumonisins in the GIT of broiler chickens...
October 5, 2017: Poultry Science
https://www.readbyqxmd.com/read/29051666/enzymatic-pectic-oligosaccharides-pos-production-from-sugar-beet-pulp-using-response-surface-methodology
#5
Neha Babbar, Winnie Dejonghe, Stefano Sforza, Kathy Elst
Pectic oligosaccharides (POS) have been indicated as novel candidate prebiotics. Traditionally, POS are produced from pectin-rich by-products using a two-step process involving extraction of the pectin, followed by its hydrolysis into POS. A one-step approach, in which the POS is directly produced from the raw material, might provide a more efficient alternative. Thus, the main aim of this paper was to investigate a one-step enzymatic hydrolysis approach to directly produce POS from sugar beet pulp (SBP). The POS yield was investigated as a function of the process parameters, as well as raw material characteristics...
October 2017: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/29046722/replacing-process-water-and-nitrogen-sources-with-biogas-slurry-during-cellulosic-ethanol-production
#6
Yang You, Bo Wu, Yi-Wei Yang, Yan-Wei Wang, Song Liu, Qi-Li Zhu, Han Qin, Fu-Rong Tan, Zhi-Yong Ruan, Ke-Dong Ma, Li-Chun Dai, Min Zhang, Guo-Quan Hu, Ming-Xiong He
BACKGROUND: Environmental issues, such as the fossil energy crisis, have resulted in increased public attention to use bioethanol as an alternative renewable energy. For ethanol production, water and nutrient consumption has become increasingly important factors being considered by the bioethanol industry as reducing the consumption of these resources would decrease the overall cost of ethanol production. Biogas slurry contains not only large amounts of wastewater, but also the nutrients required for microbial growth, e...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/29046719/conversion-of-cellulose-and-hemicellulose-of-biomass-simultaneously-to-acetoin-by-thermophilic-simultaneous-saccharification-and-fermentation
#7
Xiaojing Jia, Xiaowei Peng, Ying Liu, Yejun Han
BACKGROUND: Acetoin (3-hydroxy-2-butanone), the precursor of biofuel 2,3-butanediol, is an important bio-based platform chemical with wide applications. Fermenting the low-cost and renewable plant biomass is undoubtedly a promising strategy for acetoin production. Isothermal simultaneous saccharification and fermentation (SSF) is regarded as an efficient method for bioconversion of lignocellulosic biomass, in which the temperature optima fitting for both lignocellulose-degrading enzymes and microbial strains...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/29045027/step-up-synthesis-of-periodic-mesoporous-organosilicas-with-the-framework-of-tyrosine-tyr-pmos-and-performance-on-horseradish-peroxidase-immobilization
#8
Jianqiang Wang, Wenqi Zhang, Changqing Gu, Wenpei Zhang, Man Zhou, Zhiwei Wang, Cheng Guo, Linbing Sun
A new amino-acid bridged periodic mesoporous organosilicas (PMOs) have been constructed via hydrolysis and condensation reactions under acid condition in the presence of template. The tyrosine bissilylated organic precursor (TBOS) was first prepared through multi-step reaction using tyrosine (natural amino acid) as starting material. The PMOs with the framework of tyrosine (Tyr-PMOs) were architected by simultaneously using TBOS and TEOS as complex silicon source in the condensation process. All the Tyr-PMOs materials were characterized by XRD, FT-IR, N2 adsorption-desorption, TEM, SEM and 29Si solid-state NMR to confirm the structure...
October 18, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29043927/a-comparative-pharmacokinetic-assessment-of-a-novel-highly-bioavailable-curcumin-formulation-with-95-curcumin-a-randomized-double-blind-crossover-study
#9
Sidney J Stohs, Jin Ji, Luke R Bucci, Harry G Preuss
OBJECTIVE: Curcumin exhibits many beneficial health-promoting characteristics. However, its poor oral absorption precludes its general use. This study assessed the bioavailability of a novel curcumin formulation compared to 95% curcumin and published results for various other curcumin formulations. METHODS: A randomized, crossover, double-blind, comparator-controlled pharmacokinetic study was performed in 12 healthy adult subjects to determine the appearance of free curcumin and its metabolites curcumin sulfate and curcumin glucuronide in plasma after a single dose of a novel proprietary curcumin liquid droplet micromicellar formulation (CLDM) and unformulated 95% curcumin powder in capsule form...
October 18, 2017: Journal of the American College of Nutrition
https://www.readbyqxmd.com/read/29040864/enhanced-enzymatic-hydrolysis-by-adding-long-chain-fatty-alcohols-using-film-as-a-structure-model
#10
Zongwei Guo, Liming Zhang, Lu Zhang, Guihua Yang, Feng Xu
Many positive effects of additives on enzymatic hydrolysis of lignocellulosic materials have been investigated, but limited information has been reported on the use of long-chain fatty alcohols (LFAs) for enzymatic hydrolysis by biospired models. In this study, effects of LFAs on enzymatic hydrolysis were evaluated using biomimetic film asa structure model. LFAs clearly improved the digestibility of cellulose film from 65.1% to 77.9%, which was higher than that the digestibility of lignin-cellulose film from 53...
September 27, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29040849/synergy-of-lignocelluloses-pretreatment-by-sodium-carbonate-and-bacterium-to-enhance-enzymatic-hydrolysis-of-rice-straw
#11
Zhanhui Shen, Kejing Zhang, Mengying Si, Mingren Liu, Shengnan Zhuo, Dan Liu, Lili Ren, Xu Yan, Yan Shi
We studied a new strategy for pretreatment of rice straw (RS) to enhance enzymatic hydrolysis under mild condition. This approach uses the synergy of sodium carbonate (Na2CO3) and the bacterial strain Cupriavidus basilensis B-8 (hereafter B-8). After synergistic Na2CO3 and B-8 pretreatment (SNBP), the reducing sugar yield varied from 335.3mg/g to 799.6mg/g under different conditions. This increased by 13-31% over Na2CO3 pretreatment (284.2-719.2mg/g) and 3.42-8.15times over the untreated RS (98mg/g). Moreover, the composition of RS was changed significantly through decreases in lignin and hemicellulose...
October 6, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29040847/characterization-of-ionic-liquid-pretreated-plant-cell-wall-for-improved-enzymatic-digestibility
#12
Tirath Raj, Ruchi Gaur, Bhawna Yadav Lamba, Nitu Singh, Ravi P Gupta, Ravindra Kumar, Suresh K Puri, S S V Ramakumar
An insight into the properties of cell wall of mustard stalk (MS) pretreated by five ionic liquids (ILs) revealed ILs interaction with cellulose, hemicellulose and lignin components. Differential Scanning Calorimetry (DSC) showed increased pore size coupled with increased population of pores evoked by certain ILs in better facilitating enzymatic accessibility. Interestingly, all the five ILs predominantly increased the propensity of two pore sizes formation; 19 and 198 nm, but remarkable difference in the pore volumes of pretreated MS suggested the supremacy of [OAc](-) based ILs, resulting in higher glucose yields...
October 4, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29038760/cellobiohydrolase-b-of-aspergillus-niger-over-expressed-in-pichia-pastoris-stimulates-hydrolysis-of-oil-palm-empty-fruit-bunches
#13
James Sy-Keen Woon, Mukram M Mackeen, Rosli M Illias, Nor M Mahadi, William J Broughton, Abdul Munir Abdul Murad, Farah Diba Abu Bakar
BACKGROUND: Aspergillus niger, along with many other lignocellulolytic fungi, has been widely used as a commercial workhorse for cellulase production. A fungal cellulase system generally includes three major classes of enzymes i.e., β-glucosidases, endoglucanases and cellobiohydrolases. Cellobiohydrolases (CBH) are vital to the degradation of crystalline cellulose present in lignocellulosic biomass. However, A. niger naturally secretes low levels of CBH. Hence, recombinant production of A...
2017: PeerJ
https://www.readbyqxmd.com/read/29038283/ctx-m-15-producing-shewanella-sp-clinical-isolate-expressing-oxa-535-a-chromosome-encoded-oxa-48-variant-putative-progenitor-of-the-plasmid-encoded-oxa-436
#14
Agnès B Jousset, Laura Dabos, Rémy A Bonnin, Delphine Girlich, Anaïs Potron, Nicolas Cabanel, Laurent Dortet, Philippe Glaser, Thierry Naas
Shewanella spp. constitute a reservoir of antibiotic resistance determinants. In a bile sample, we have identified three Extended Spectrum β-lactamase (ESBL)-producing bacteria (Escherichia coli, Klebsiella pneumoniae and Shewanella sp. JAB-1) isolated from a child suffering from cholangitis. Our objectives were to characterize the genome and the resistome of the first ESBL-producing isolate of the genus Shewanella and determine whether plasmidic exchange occurred between the three-bacterial species. Bacterial isolates were characterized using MALDI-TOF, standard biochemical tools and antimicrobial susceptibility testing...
October 16, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29035726/nonionic-surfactants-enhanced-enzymatic-hydrolysis-of-cellulose-by-reducing-cellulase-deactivation-caused-by-shear-force-and-air-liquid-interface
#15
Hongming Lou, Meijun Zeng, Qiaoyan Hu, Cheng Cai, Xuliang Lin, Xueqing Qiu, Dongjie Yang, Yuxia Pang
Effects of nonionic surfactants on enzymatic hydrolysis of Avicel at different agitation rates and solid loadings and the mechanism were studied. Nonionic surfactants couldn't improve the enzymatic hydrolysis efficiency at 0 and 100rpm but could enhance the enzymatic hydrolysis significantly at high agitation rate (200 and 250rpm). Cellulase was easily deactivated at high agitation rate and the addition of nonionic surfactants can protect against the shear-induced deactivation, especially when the cellulase concentration was low...
July 14, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/29035043/remarkable-reactivity-differences-between-glucosides-with-identical-leaving-groups
#16
Tianmeng Duo, Kyle Robinson, Ian R Greig, Hong-Ming Chen, Brian O Patrick, Stephen G Withers
Two isomeric aryl 2-deoxy-2-fluoro-β-glucosides react with a β-glucosidase at rates differing by 10(6) fold, despite the fact that they release the same aromatic aglycone. In contrast the equivalent glucoside substrates react with essentially identical rate constants. Insight into the source of these surprising rate differences was obtained through a comprehensive study of the non-enzymatic (spontaneous) hydrolysis of these same substrates, wherein an approximate 10(5) fold difference in rates was measured, clarifying that the differences were inherent, rather than being due to specific interactions with the enzyme...
October 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29030666/lc-pda-apciitms-identification-of-algal-carotenoid-and-oxysterol-precursors-to-fatty-acid-esters-in-hydrolyzed-extracts-of-the-freshwater-mussel-dreissena-bugensis
#17
Maxime C Bridoux, Monika Sobiechowska, Alicia Pérez-Fuentetaja, Katherine T Alben
Carotenyl fatty acid esters (carotenyl-FAEs) were extracted in acetone from freeze-dried Dreissena bugensis (Lakes Erie and Ontario) and hydrolyzed to identify the carotenoid precursors. Analysis by liquid chromatography (LC) with photodiode array (PDA) and atmospheric pressure chemical ionization-ion trap mass spectrometry (APCIitMS) revealed the major hydrolysis products: fucoxanthinol (FOH) from fucoxanthin (FX, diatoms); mactraxanthin (MX) from violaxanthin (VX, chlorophytes); 4-fold higher levels of an unknown, tentatively identified as an adduct of two closely eluting C27H46O3 and C27H48O3 steryl triols...
October 13, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/29029746/liquid-chromatography-tandem-mass-spectrometric-determination-of-triterpenes-in-human-fluids-evaluation-of-markers-of-dietary-intake-of-olive-oil-and-metabolic-disposition-of-oleanolic-acid-and-maslinic-acid-in-humans
#18
Oscar J Pozo, Mitona Pujadas, Sarah Biel Gleeson, Maria Dolores Mesa-García, Antoni Pastor, Aristotelis Kotronoulas, Montserrat Fitó, Maria-Isabel Covas, José Ramón Fernández Navarro, Juan Antonio Espejo, Estefania Sanchez-Rodriguez, Rosa Marchal, Miguel Angel Calleja, Rafael de la Torre
Olive oil is rich in several minor components like maslinic (MA) and oleanolic (OA) acids which have cardioprotective, antitumor, and anti-inflammatory properties. In order to assess the health benefits in humans provided by the olive oil triterpenes (MA and OA), suitable analytical methods able to quantify the low concentrations expected in human fluids are required. In this study, the LC-MS/MS quantification of both OA and MA in plasma and urine has been evaluated. The plasmatic method is based on the direct determination of the analytes...
October 16, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/29027934/angiotensin-i-converting-enzyme-ace-inhibitory-activity-antioxidant-properties-phenolic-content-and-amino-acid-profiles-of-fucus-spiralis-l-protein-hydrolysate-fractions
#19
Lisete Paiva, Elisabete Lima, Ana Isabel Neto, José Baptista
Food protein-derived hydrolysates with multi-bioactivities such as antihypertensive and antioxidant properties have recently received special attention since both activities can play significant roles in preventing cardiovascular diseases. This study reports, for the first time, the angiotensin I-converting enzyme (ACE)-inhibition and antioxidant properties of ultrafiltrate fractions (UF) with different molecular weight ranges (<1, 1-3 and ≥3 kDa) obtained from Fucus spiralis protein hydrolysate (FSPH) digested with cellulase-bromelain...
October 13, 2017: Marine Drugs
https://www.readbyqxmd.com/read/29024928/zinc-inhibits-collagenolysis-by-cathepsin-k-and-matrix-metalloproteinases-in-demineralized-dentin-matrix
#20
Pinar Altinci, Roda Seseogullari-Dirihan, Gulsen Can, David Pashley, Arzu Tezvergil-Mutluay
The enzymatic degradation of dentin organic matrix occurs via both the action of matrix metalloproteinases (MMPs) and cysteine cathepsins (CCs). Zinc can prevent collagen hydrolysis by MMPs. However, its effect on the activity of dentin-bound CCs is not known. The aim of this study was to investigate the effect of zinc on matrix-bound cathepsin K and MMP activity in dentin. Completely demineralized dentin beams were divided into test groups (n = 9) and incubated at 37°C in an incubation media (1 mL) containing ZnCl2 of 0...
October 13, 2017: Caries Research
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