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1.
Anal Chem ; 93(36): 12434-12440, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34473470

RESUMO

The ability to accurately diagnose cancer is the cornerstone of early cancer treatment. The mitochondria in cancer cells maintain a higher pH and lower polarity relative to that in normal cells. A probe that reports signals only when both conditions are met may provide a reliable method for cancer detection with reduced false positives. Here, we construct an AND logic gate fluorescent probe using mitochondrial microenvironments as inputs. Utilizing the hydrolysis of a coumarin scaffold, the probe generates fluorescence signals ("ON") only when high pH (>7.0) and low polarity conditions exist simultaneously. Additionally, the higher mitochondrial membrane potential in cancer cells provides an additional level of selectivity because probe has increased affinity for cancer cell mitochondria. These capabilities endow the probe with a high contrast fluorescence diagnosis ability of cancer at cellular and tissue levels (as high as 51.9 fold), which is far exceeding the clinic threshold of 2.0 fold.


Assuntos
Lógica , Neoplasias , Cumarínicos , Fluorescência , Corantes Fluorescentes , Hidrólise , Neoplasias/diagnóstico
2.
Appl Microbiol Biotechnol ; 105(18): 6793-6803, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34477943

RESUMO

Some microbial-associated molecular patterns (MAMPs), like glucan oligosaccharides, can be recognized by pattern recognition receptors (PRRs) of plant to elicit further immunity response. In this study, a novel glycoside hydrolase family 55 ß-1,3-glucanase (AcGluA) from Archangium sp. strain AC19 was cloned and expressed in Escherichia coli. Among the reported ß-1, 3-glucanases from the glycoside hydrolase 55 family, the purified AcGluA exhibited the highest activity on laminarin at pH 6.0 and 60 °C with 112.3 U/mg. Activity of AcGluA was stable in the range of pH 4.0-9.0 and at temperatures below 60 °C. The Km and Vmax of AcGluA for laminarin were 3.5 mg/ml and 263.5 µmol/(ml·min). AcGluA hydrolyzed laminarin into a series of oligosaccharides, suggesting it was an endo-ß-1,3-glucanase. The high dose of oligosaccharides (1600 mg/l) had conspicuous biocontrol efficacy on the defense of rice seedlings to Magnaporthe oryzae, which provided a new idea for the development of green biopesticide.Key points• The AcGluA was determined bacteria-derived ß-1,3-glucanases in the GH55 family.• The AcGluA showed the highest activity towards laminarin among reported GH55 family.• The hydrolysates of laminarin showed conspicuous biocontrol efficacy to M. oryzae.


Assuntos
Ascomicetos , Glicosídeo Hidrolases , Ascomicetos/metabolismo , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Hidrólise , Especificidade por Substrato
3.
Nanoscale ; 13(29): 12546-12552, 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34477613

RESUMO

A metal-organic framework (MOF) material was prepared from 2-aminoterephthalic acid and aluminum chloride with a solvothermal synthesis protocol. The as-prepared MOF material named NH2-MIL-53(Al) emitted a very intensive fluorescent (FL) signal after it was hydrolyzed in alkaline solution for releasing numerous FL ligands NH2-H2BDC. Thus it can be considered as a sensitive FL probe for studying biorecognition events. In this proof-of-principle work, a double-site recognition method was established to quantify Staphylococcus aureus (S. aureus) relying on the alkaline hydrolysis property of the MOF material. In particular, magnetic beads (MBs) modified with pig IgG were adopted for binding S. aureus based on the strong affinity between pig IgG and protein A on the bacterial surface. Meanwhile, MOF NH2-MIL-53(Al)-tagged teicoplanin (TEI) was adopted for tracing the target bacteria. By hydrolyzing the MOF material bound on the MBs to trigger the FL signal, S. aureus can be quantified with a dynamic range of 3.3 × 103-3.3 × 107 CFU mL-1 and a detection limit of 5.3 × 102 CFU mL-1 (3σ). The method can exclude efficiently the interference from other common bacteria. It has been applied to quantify S. aureus in saliva, pomegranate green tea, glucose injection and milk samples with satisfactory results, verifying the application potential for analyzing various types of real samples contaminated with S. aureus.


Assuntos
Estruturas Metalorgânicas , Infecções Estafilocócicas , Animais , Corantes Fluorescentes , Hidrólise , Infecções Estafilocócicas/diagnóstico , Staphylococcus aureus , Suínos
4.
Anal Chim Acta ; 1178: 338808, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34482859

RESUMO

In the presented study, the usability of hydrolytic enzyme immobilized magnetic nanoparticles as an extraction agent for the microextraction of metal ions from food samples was investigated. α-amylase modified magnetic carbon nanotubes (α-amylase-Fe3O4/MWCNTs) was used as an extraction agent for direct microextraction of trace arsenic from food sample phase into liquid phase medium prior to its ICP-MS determination. In extraction studies using hydrolytic enzymes, it is impossible to recover the free soluble enzyme after extraction without losing its activity. In our study, this problem was overcome by immobilizing the hydrolytic enzyme on magnetic support. In this way, α-amylase-Fe3O4/MWCNTs as an extraction agent with a reuse property of at least six times was used. α-amylase-Fe3O4/MWCNTs was characterized by FT-IR, XRD, SEM, SEM-EDX, VSM, TGA, and DTG techniques. Optimization of the presented method was performed using 1568 A rice flour certified reference material. Analytical parameters such as type of hydrolytic enzyme, pH and volume of the aqueous phase, extraction temperature and ultrasonic irridation time were optimized. The microextraction step was performed in ultrasonic water bath within only ∼15 min. Limit of detection (LOD), limit of quantification (LOQ) and relative standard deviation (RSD %) values for the developed method were found to be 14.3 µg kg-1, 47.3 µg kg-1 and 7.5%, respectively. The method was successfully applied to the analysis of arsenic contents of different rice and flour samples.


Assuntos
Microextração em Fase Líquida , Nanopartículas de Magnetita , Nanotubos de Carbono , Hidrólise , Limite de Detecção , Magnetismo , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier
5.
Enzyme Microb Technol ; 150: 109893, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34489046

RESUMO

In this study, a GH26 endo-mannanase (Man26A) from an Aspergillus niger ATCC 10864 strain, with a molecular mass of 47.8 kDa, was cloned in a yBBH1 vector and expressed in Saccharomyces cerevisiae Y294 strain cells. Upon fractionation by ultra-filtration, the substrate specificity and substrate degradation pattern of the endo-mannanase (Man26A) were investigated using ivory nut linear mannan and two galactomannan substrates with varying amounts of galactosyl substitutions, guar gum and locust bean gum. Man26A exhibited substrate specificity in the order: locust bean gum ≥ ivory nut mannan > guar gum; however, the enzyme generated more manno-oligosaccharides (MOS) from the galactomannans than from linear mannan during extended periods of mannan hydrolysis. MOS with a DP of 2-4 were the major products from mannan substrate hydrolysis, while guar gum also generated higher DP length MOS. All the Man26A generated MOS significantly improved the growth (approximately 3-fold) of the probiotic bacterial strains Streptococcus thermophilus and Bacillus subtilis in M9 minimal medium. Ivory nut mannan and locust bean gum derived MOS did not influence the auto-aggregation ability of the bacteria, while the guar gum derived MOS led to a 50 % reduction in bacterial auto-aggregation. On the other hand, all the MOS significantly improved bacterial biofilm formation (approximately 3-fold). This study suggests that the prebiotic characteristics exhibited by MOS may be dependent on their primary structure, i.e. galactose substitution and DP. Furthermore, the data suggests that the enzyme-generated MOS may be useful as potent additives to dietary foods.


Assuntos
Aspergillus niger , Prebióticos , Aspergillus niger/genética , Hidrólise , Mananas , Oligossacarídeos , beta-Manosidase/genética
6.
Bioresour Technol ; 340: 125711, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34385124

RESUMO

In this study, the anti-pollutant macrophyte Typha domingensis is exploited for the production of highly concentrated second-generation glucose. A two-stage starch and cellulose enzymatic hydrolysis process is compared for the first time with a single-stage simultaneous starch and cellulose hydrolysis approach, with the former achieving enhanced glucose production, making it more promising for large-scale deployment. The proposed two-stage process is optimized via the Box-Behnken response surface methodology achieving glucose yield values of 74.4% and 71.7% with respect to the starch and cellulose fraction, respectively. Elevated shaking rates are shown to exert a positive effect on both starch and cellulose enzymatic hydrolysis only under high initial substrate concentrations and high initial enzyme to substrate ratios, indicating the importance of accounting for the synergies between key process variables when aiming to increase glucose production. The findings of the presented experimental framework aspire to support future scale-up studies and techno-economic assessments.


Assuntos
Poluentes Ambientais , Glucose , Biomassa , Celulose , Etanol , Hidrólise
7.
J Agric Food Chem ; 69(36): 10657-10668, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34387985

RESUMO

High-melting-temperature solid triacylglycerol (TAG) is the main source of controversy with regard to the nutritional assessment of milk fat. This study investigated the microscopic changes and hydrolysis kinetics of milk fat globules (MFGs) reconstituted with butterfat and its primary fractions (30S, 20S, and 20L) during in vitro digestion. The 30S, 20S, and 20L on behalf of high-, medium- and low-melting-temperature fractions, respectively, had well-distinguished melting temperatures (42.1, 38.9, and 22.0 °C) and long-chain saturated TAG contents (19.3, 3.2, and 1.8%). The results revealed that the gastrointestinal fate of these butterfat fractions varied greatly with their TAG composition, and the gastric phase was a sensitive target in terms of the physiological site. The 20S- and 30S-reconstituted MFG emulsions during gastric digestion compared to that of 20L had higher extensive aggregation, lower hydrolysis extent (29.8, 28.0, and 57.3%, respectively), and slower apparent hydrolysis rate constants k (2.4, 2.1, and 6.1 min-1, respectively).


Assuntos
Digestão , Animais , Bovinos , Hidrólise , Cinética , Temperatura , Triglicerídeos
8.
Eur J Pharm Sci ; 166: 105980, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34419573

RESUMO

Two of the most widely used surfactants to stabilize biologicals against e.g. interfacial stresses are polysorbate 20 (PS20) and polysorbate 80 (PS80). In recent years, numerous cases of hydrolytic polysorbate (PS) degradation in liquid formulations of biopharmaceuticals have been observed. Concomitant with the degradation of PSs, formulated proteins become inherently instable and more susceptible to aggregation. Furthermore, poorly soluble fatty acids (FA) are released from the PSs, which might lead to FA precipitation and the formation of visible and subvisible particles. Therefore, possible particle inducing factors have to be monitored closely. The major root cause of hydrolytic PS degradation in biologicals is the presence of enzymatic active host cell proteins (HCP), like lipases and esterases, which are co-purified with the active pharmaceutical ingredient. Such contaminants can be detected via their hydrolytic activity, either using ester-based substrates or PS itself. However, each approach has its up- and downsides, which makes the comparison of the results from other publications difficult. It was therefore the aim of the present study to investigate the impact of lipase specificities on the assay readouts. This study evaluates three different surrogate (model) lipases with distinctively different degradation kinetics and substrate specificities using specific analytical methods. The analytical panel contains on one hand two lipase activity assays with ester-based substrates, either detecting the release of para-nitrophenol or 4-methylumbelliferone, and on the other hand two PS-based monitoring analyses (fluorescence micelle assay and reverse phase high performance liquid chromatography - charged aerosol detection), which detect hydrolytic "activity" directly in the target substrate. Thereby, strengths and weaknesses of each assay are discussed, and recommendations are made for the respective use cases. Our results show that the determined lipase activities vary not only from assay to assay, but also significantly for the lipase tested, thus showing a different degradation fingerprint in the RP-HPLC-CAD chromatogram. This demonstrates that a comprehensive monitoring approach is essential to assess potential HCP contaminations.


Assuntos
Lipase , Polissorbatos , Cromatografia Líquida de Alta Pressão , Hidrólise , Cinética , Tensoativos
9.
Int J Mol Sci ; 22(16)2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34445355

RESUMO

Recently, lithium nitride (Li3N) has been proposed as a chemical warfare agent (CWA) neutralization reagent for its ability to produce nucleophilic ammonia molecules and hydroxide ions in aqueous solution. Quantum chemical calculations can provide insight into the Li3N neutralization process that has been studied experimentally. Here, we calculate reaction-free energies associated with the Li3N-based neutralization of the CWA VX using quantum chemical density functional theory and ab initio methods. We find that alkaline hydrolysis is more favorable to either ammonolysis or neutral hydrolysis for initial P-S and P-O bond cleavages. Reaction-free energies of subsequent reactions are calculated to determine the full reaction pathway. Notably, products predicted from favorable reactions have been identified in previous experiments.


Assuntos
Descontaminação , Compostos de Lítio/química , Compostos Organotiofosforados/química , Água/química , Amônia/química , Substâncias para a Guerra Química/química , Substâncias para a Guerra Química/farmacologia , Descontaminação/métodos , Hidrólise/efeitos dos fármacos , Cinética , Lítio/química , Modelos Moleculares , Compostos Organotiofosforados/farmacologia , Teoria Quântica
10.
Nucleic Acids Res ; 49(15): 8777-8784, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34365509

RESUMO

Transcribing RNA polymerase (RNAP) can fall into backtracking, phenomenon when the 3' end of the transcript disengages from the template DNA. Backtracking is caused by sequences of the nucleic acids or by misincorporation of erroneous nucleotides. To resume productive elongation backtracked complexes have to be resolved through hydrolysis of RNA. There is currently no consensus on the mechanism of catalysis of this reaction by Escherichia coli RNAP. Here we used Salinamide A, that we found inhibits RNAP catalytic domain Trigger Loop (TL), to show that the TL is required for RNA cleavage during proofreading of misincorporation events but plays little role during cleavage in sequence-dependent backtracked complexes. Results reveal that backtracking caused by misincorporation is distinct from sequence-dependent backtracking, resulting in different conformations of the 3' end of RNA within the active center. We show that the TL is required to transfer the 3' end of misincorporated transcript from cleavage-inefficient 'misincorporation site' into the cleavage-efficient 'backtracked site', where hydrolysis takes place via transcript-assisted catalysis and is largely independent of the TL. These findings resolve the controversy surrounding mechanism of RNA hydrolysis by E. coli RNA polymerase and indicate that the TL role in RNA cleavage has diverged among bacteria.


Assuntos
RNA Polimerases Dirigidas por DNA/metabolismo , RNA Mensageiro/metabolismo , Elongação da Transcrição Genética , Domínio Catalítico , RNA Polimerases Dirigidas por DNA/antagonistas & inibidores , RNA Polimerases Dirigidas por DNA/química , Depsipeptídeos/química , Depsipeptídeos/farmacologia , Escherichia coli/enzimologia , Escherichia coli/genética , Hidrólise , Clivagem do RNA
11.
Langmuir ; 37(34): 10319-10329, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34407374

RESUMO

This study highlights the role of time-dependent hydrolysis of ionic liquid anion, [BF4]-, of ionic liquid (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate, [C2mim][BF4], which results in ever-changing pH conditions. Such pH changes along with the ionic interactions bring conformational changes in bovine serum albumin (BSA), leading to the formation of amyloid fibers at 37 °C without external control of pH or addition of electrolyte. The fibrillation of BSA occurs spontaneously with the addition of IL; however, the highest growth rate has been observed in aqueous solution of 10% IL (v/v %) among investigated systems. Thioflavin T (ThT) fluorescence emission has been employed to monitor the growth and development of ß-sheet content in amyloid fibrils. The structural alterations in BSA have also been investigated using intrinsic fluorescence measurements. Circular dichroism (CD) measurements confirmed the formation of amyloid fibrils. Transmission electron microscopy (TEM) has been explored to establish the morphologies of BSA fibrils at different intervals of time, whereas atomic force microscopy (AFM) has established the helically twisted nature of grown amyloid fibrils. The docking studies have been utilized to understand the insertion of IL ions in different domains of BSA, which along with decreased pH cause the unfolding and growth of BSA into amyloid fibrils. It is expected that the results obtained from this study would help to understand the impact of IL containing [BF4]- anion on protein stability and aggregation along with providing a new platform to control the formation of amyloid fibrils and other biomaterials driven via ionic interactions and alterations in pH.


Assuntos
Líquidos Iônicos , Soroalbumina Bovina , Amiloide , Dicroísmo Circular , Hidrólise , Temperatura
12.
Science ; 373(6553)2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34437092

RESUMO

Systematic and extensive investigation of enzymes is needed to understand their extraordinary efficiency and meet current challenges in medicine and engineering. We present HT-MEK (High-Throughput Microfluidic Enzyme Kinetics), a microfluidic platform for high-throughput expression, purification, and characterization of more than 1500 enzyme variants per experiment. For 1036 mutants of the alkaline phosphatase PafA (phosphate-irrepressible alkaline phosphatase of Flavobacterium), we performed more than 670,000 reactions and determined more than 5000 kinetic and physical constants for multiple substrates and inhibitors. We uncovered extensive kinetic partitioning to a misfolded state and isolated catalytic effects, revealing spatially contiguous regions of residues linked to particular aspects of function. Regions included active-site proximal residues but extended to the enzyme surface, providing a map of underlying architecture not possible to derive from existing approaches. HT-MEK has applications that range from understanding molecular mechanisms to medicine, engineering, and design.


Assuntos
Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Fosfatase Alcalina/antagonistas & inibidores , Fosfatase Alcalina/química , Biocatálise , Domínio Catalítico , Flavobacterium/enzimologia , Hidrólise , Cinética , Microfluídica , Modelos Moleculares , Mutação , Oxigênio/metabolismo , Fosfatos/metabolismo , Conformação Proteica , Dobramento de Proteína , Termodinâmica
13.
Appl Microbiol Biotechnol ; 105(18): 6759-6778, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34458936

RESUMO

The genus Cohnella belongs to a group of Gram-positive endospore-forming bacteria within the Paenibacillaceae family. Although most species were described as xylanolytic bacteria, the literature still lacks some key information regarding their repertoire of xylan-degrading enzymes. The whole genome sequence of an isolated xylan-degrading bacterium Cohnella sp. strain AR92 was found to contain five genes encoding putative endo-1,4-ß-xylanases, of which four were cloned, expressed, and characterized to better understand the contribution of the individual endo-xylanases to the overall xylanolytic properties of strain AR92. Three of the enzymes, CoXyn10A, CoXyn10C, and CoXyn11A, were shown to be effective at hydrolyzing xylans-derived from agro-industrial, producing oligosaccharides with substrate conversion values of 32.5%, 24.7%, and 10.6%, respectively, using sugarcane bagasse glucuronoarabinoxylan and of 29.9%, 19.1%, and 8.0%, respectively, using wheat bran-derived arabinoxylan. The main reaction products from GH10 enzymes were xylobiose and xylotriose, whereas CoXyn11A produced mostly xylooligosaccharides (XOS) with 2 to 5 units of xylose, often substituted, resulting in potentially prebiotic arabinoxylooligosaccharides (AXOS). The endo-xylanases assay displayed operational features (temperature optima from 49.9 to 50.4 °C and pH optima from 6.01 to 6.31) fitting simultaneous xylan utilization. Homology modeling confirmed the typical folds of the GH10 and GH11 enzymes, substrate docking studies allowed the prediction of subsites (- 2 to + 1 in GH10 and - 3 to + 1 in GH11) and identification of residues involved in ligand interactions, supporting the experimental data. Overall, the Cohnella sp. AR92 endo-xylanases presented significant potential for enzymatic conversion of agro-industrial by-products into high-value products.Key points• Cohnella sp. AR92 genome encoded five potential endo-xylanases.• Cohnella sp. AR92 enzymes produced xylooligosaccharides from xylan, with high yields.• GH10 enzymes from Cohnella sp. AR92 are responsible for the production of X2 and X3 oligosaccharides.• GH11 from Cohnella sp. AR92 contributes to the overall xylan degradation by producing substituted oligosaccharides.


Assuntos
Bacillales , Saccharum , Endo-1,4-beta-Xilanases/genética , Hidrólise , Oligossacarídeos , Xilanos
14.
Water Res ; 203: 117555, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34416648

RESUMO

The centrate produced from a thermal hydrolysis pretreatment coupled anaerobic digestion (THP-AD) system is generally characterized by high concentrations of ammonium and recalcitrant organics. In this study, a cost-effective partial nitritation-anammox (PN/A) process was developed to evaluate the potential challenges in THP-AD centrate treatment. The results show ammonium oxidizing bacteria (AOB) and anammox bacteria were seriously inhibited by THP-AD centrate, while long-term acclimation together with aeration optimization can mitigate such inhibition. A nitrogen removal rate (NRR) of 0.55 kg N/m3/d was obtained and maintained with 60% THP-AD centrate as feed. However, 100% THP-AD centrate caused sludge wash-out from PN reactor due to excessive polymer and high solids in influent. The alkalinity deficit also reduced the AOB activity. Moreover, anammox activity and overall NRR also declined (to 0.37 kg N/m3/d). The organics transformation mainly occurred in PN reactor with very low removal efficiency due to their recalcitrant characteristics. The humic acid-like, fulvic acid-like substances and building blocks were revealed as the major organic compounds in THP-AD centrate (51.5-53.8% TOC), which likely contributed to the recalcitrant. Nitrosomonas and Candidatus Brocadia were the major AOB and anammox bacteria in the PN and anammox reactors respectively. With the increased THP-AD centrate proportion in the feed, the abundance of both population declined. Interestingly, Denitratisoma, being the major denitrifying bacteria in anammox reactor, had relatively stable abundance (7.0-7.9%) when THP-AD centrate was improved from 3 and 100%, suggesting the inhibition on anammox bacteria was not due to the overgrowth of denitrifying microorganism despite the high organics loading rate. Overall, this study provides a guide to develop the energy-saving PN/A process for THP-AD centrate treatment by pointing out potential challenges and mitigating strategies.


Assuntos
Compostos de Amônio , Desnitrificação , Biomassa , Reatores Biológicos , Hidrólise , Nitrogênio , Oxirredução , Esgotos
15.
Bioresour Technol ; 340: 125740, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34426233

RESUMO

The prerequisite for cellulosic biochemical production from lignocellulosic materials is efficient enzymatic hydrolysis that is a complicated heterogeneous catalytic process and affected by the complex lignin-cellulose-hemicellulose network. Understanding the main influencing factors for enzymatic hydrolysis is of substantial significance to guide the design of a biorefinery process. An experimental study of the pretreatment indicated that acid pretreatment is preferable for herbaceous feedstocks. Therefore, the classic dilute sulfuric acid pretreatment was utilized to hydrolyze and remove hemicellulose from three representative types of agricultural straws at various intensities. From the enzymatic hydrolysis of residual cellulose perspective, the crystallinity index and enzyme accessibility of the pretreated materials were also mathematically correlated to hemicellulose removals, respectively. For the better insight and understanding of the mathematical logics, the linear and nonlinear kinetic models were therefore compared, and the relationship was established by the five-parameter logistic equations and Allosteric sigmoidal models with well fittings.


Assuntos
Celulose , Ácidos Sulfúricos , Hidrólise , Lignina
16.
Bioresour Technol ; 340: 125650, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34426236

RESUMO

The study evaluates the potential of different vegetable wastes namely, composite vegetable waste (CVW), potato waste (PW), sweet potato waste (SPW) and yam waste (YW) as an alternative feedstock for the production of renewable sugars. Thermal assisted chemical pretreatment followed by enzymatic saccharification yielded maximum sugars (0.515 g/g CVW, 0.56 g/g PW, 0.57 g/g SPW and 0.56 g/g YW) with total carbohydrate depolymerization of 95.01%, 88.30%, 90.32% and 88.59% respectively. Obtained sugars were valorized into bioethanol through fermentation using S. cerevisiae by optimizing the pH and temperature. The highest ethanol yield of 251.85 mg/g was obtained from SPW at 35°C followed by YW (240.98 mg/g), PW (235.4 mg/g) and CVW (125.6 mg/g) at pH 5.0. Utilizing the abundantly available vegetable wastes as a renewable feedstock for reducing sugars and subsequent bioethanol production will influence the economics and sustainability of the process positively in circular biorefinery format.


Assuntos
Etanol , Açúcares , Biocombustíveis , Fermentação , Hidrólise , Saccharomyces cerevisiae , Verduras
17.
Bioresour Technol ; 340: 125726, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34426244

RESUMO

This study assesses the economic performance of a biorefinery producing xylo-oligosaccharides (XOS) from miscanthus by autohydrolysis and purification based on a rigorous model developed in ASPEN Plus. Varied biorefinery capacities (50-250 oven dry metric ton (ODMT)/day) and three XOS content levels (80%, 90%, 95%) are analyzed. The XOS minimum selling price (XOS MSP) is varied between $3,430-$7,500, $4,030-$8,970, and $4,840-$10,640 per metric ton (MT) for 80%, 90%, and 95% content, respectively. The results show that increasing biorefinery capacity can significantly reduce the XOS MSP and higher purity leads to higher XOS MSP due to less yield, and higher capital and operating costs. This study also explores another system configuration to produce high-value byproducts, cellulose microfiber, by utilizing the cellulose to produce microfiber instead of combusting for energy recovery. The XOS MSP of cellulose microfiber case is $2,460-$7,040/MT and thus exhibits potential economic benefits over the other cases.


Assuntos
Celulose , Oligossacarídeos , Biomassa , Hidrólise , Lignina
18.
J Environ Manage ; 297: 113422, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34351298

RESUMO

Increase in human population, rapid industrialization, excessive utilization of fossil fuel utilization and anthropogenic activities have caused serious threats to the environment in terms of greenhouse gas emissions (GHGs), global warming, air pollution, acid rain, etc. This destruction in sustainability can be averted by a paradigm shift in the fuel production from fossil resources to bioenergy. Amongst different forms of bioenergy, lignocellulosic biomass can be utilized as an attractive substrate for the production of several high-value products owing to its renewability, easy availability, and abundance. Additionally, utilization of these waste biomasses reduces the environmental hazards associated with its disposal. Impedance of lignin and crystalline nature of cellulose pose major bottlenecks in biomass based energy. Though, several physio-chemicals processes are recommended as mitigation route but none of them seems to be promising for large scale application. In recent years, a right fusion of biological treatment combined with nanotechnology for efficient pretreatment and subsequent hydrolysis of biomass by ubiquitous enzymes seems to be promising alternative. In addition, to overcome these difficulties, nanotechnology-based methods have been recently adopted in catalytic valorization of lignocellulosic biomass. The present review has critically discussed the application of nano-biotechnology in lignocellulosic biomass valorization in terms of pretreatment and hydrolysis. A detailed discussion on the application of various nanoparticles in these processes, enzyme immobilization and end-production utilization is presented in this review. Finally, the review emphasizes the major challenges of this process along with different routes and recommendations to address the issues.


Assuntos
Biotecnologia , Lignina , Biomassa , Humanos , Hidrólise
19.
BMC Res Notes ; 14(1): 315, 2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404457

RESUMO

OBJECTIVES: Breast cancer cell growth and proliferation requires lipids for energy production, cell membrane synthesis, or as signaling molecules. Lipids can be delivered to cells by lipoprotein lipase (LPL), an extracellular lipase that hydrolyzes triacylglycerols and phospholipids from lipoproteins, that is expressed by adipose tissue and some breast cancer cell lines. Studies have shown that lipoprotein hydrolysis products induce pro-inflammatory cytokine secretion by endothelial cells. Thus, our objective was to determine if hydrolysis products generated by LPL from total lipoproteins can also promote pro-inflammatory cytokine secretion from breast cancer cells. RESULTS: Using cytokine arrays, we found that MDA-MB-231 cells increased secretion of seven cytokines in response to treatment with lipoprotein hydrolysis products. In contrast, MCF-7 cells showed decreased secretion of two cytokines. Expanding the analysis to additional cell lines by ELISA, we found increased secretion of TNF-α and IL-6 by MDA-MB-468 cells, and increased secretion of IL-4 by MDA-MB-468 and SKBR3 cells. The changes to cytokine secretion profiles of the breast cancer cell types examined, including the non-cancerous MCF-10a breast cells, were independent of increased cell metabolic activity. These results provide information on how lipoprotein hydrolysis products within the tumor microenvironment might affect breast cancer cell viability and progression.


Assuntos
Neoplasias da Mama , Neoplasias de Mama Triplo Negativas , Citocinas , Células Endoteliais , Feminino , Humanos , Hidrólise , Lipase Lipoproteica , Macrófagos , Microambiente Tumoral
20.
Nat Commun ; 12(1): 4754, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362932

RESUMO

Chaperonins are homo- or hetero-oligomeric complexes that use ATP binding and hydrolysis to facilitate protein folding. ATP hydrolysis exhibits both positive and negative cooperativity. The mechanism by which chaperonins coordinate ATP utilization in their multiple subunits remains unclear. Here we use cryoEM to study ATP binding in the homo-oligomeric archaeal chaperonin from Methanococcus maripaludis (MmCpn), consisting of two stacked rings composed of eight identical subunits each. Using a series of image classification steps, we obtained different structural snapshots of individual chaperonins undergoing the nucleotide binding process. We identified nucleotide-bound and free states of individual subunits in each chaperonin, allowing us to determine the ATP occupancy state of each MmCpn particle. We observe distinctive tertiary and quaternary structures reflecting variations in nucleotide occupancy and subunit conformations in each chaperonin complex. Detailed analysis of the nucleotide distribution in each MmCpn complex indicates that individual ATP binding events occur in a statistically random manner for MmCpn, both within and across the rings. Our findings illustrate the power of cryoEM to characterize a biochemical property of multi-subunit ligand binding cooperativity at the individual particle level.


Assuntos
Trifosfato de Adenosina/metabolismo , Microscopia Crioeletrônica , Chaperoninas do Grupo II/química , Chaperoninas do Grupo II/metabolismo , Chaperoninas/metabolismo , Hidrólise , Mathanococcus/metabolismo , Modelos Moleculares , Conformação Proteica , Dobramento de Proteína , Subunidades Proteicas/metabolismo
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