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1.
Protein Pept Lett ; 28(12): 1372-1378, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34711150

RESUMO

BACKGROUND: Amylases are used in several industrial and biotechnological sectors, including those producing textiles, detergents, paper and bakery products. OBJECTIVE: This study aimed to purify an industrially important α-amylase from Bacillus sp. For this purpose, a single and rapid α-amylase purification was performed using the starch affinity method. METHODS: Characterization of the purified enzyme was determined by investigating temperature, pH stability, detergents, and metal ions. RESULTS: The purification coefficient of 29.8-fold with a yield of 9.2% was found. The molecular weight of the purified α-amylase was determined to be 53 kDa by SDS-PAGE, and thermostability was confirmed with 100% activity at 30ºC and 40ºC after 1 h. The purified enzyme was stable over a wide range of pH values, with optimum activity at pH 6.0, 7.0 and 8.0 after 2 h. The study also investigated the effects of the metal ions and detergents on the purified amylase and found that Mg2+ and Ca2+ ions were the activators of the enzyme, while Zn2+, Co2+ and Na+ ions decreased the activity. Furthermore, Hg2+; indicated complete inhibition of amylase activity. The detergents Triton X-100 and Tween 20 increased the α-amylase activity, while sodium dodecyl sulfate inhibited the activity. CONCLUSION: The purified α-amylase obtained from Bacillus sp. is considered to be environmentally friendly, can be processed in a short time, and has a low cost.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias , Temperatura Alta , Microbiologia do Solo , alfa-Amilases , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Estabilidade Enzimática , alfa-Amilases/química , alfa-Amilases/isolamento & purificação
2.
Int J Biol Macromol ; 192: 64-71, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34592224

RESUMO

Purification of extracellular α-amylase from Bacillus subtilis was carried out via fractional precipitation by acetone and ion exchange chromatography. These steps provide fast precipitation as well as purification of α-amylase to improve enzyme purity, activity and stability. Compared with two-phase methods in which the yield was less than 1, this method resulted in a yield of more than 3. Moreover, 95% of acetone was recovered that enhanced the economy of the downstream process. Using the data provided by 2D electrophoresis, purification was done by a single step ion exchange chromatography. The enzyme exhibited a molecular mass (SDS-PAGE) of 50KD and the pI of 5. Maximum "yield" and "purification fold" were achieved through optimization of operation parameters such as volume and flowrate of loaded protein using response surface methodology (RSM). 0.5ml of loaded protein at a flow rate of 0.5 ml/min was purified as 48 folds and achieved a specific activity of 524 U/mg.


Assuntos
Bacillus subtilis/enzimologia , alfa-Amilases/química , alfa-Amilases/isolamento & purificação , Acetona , Análise de Variância , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Ativação Enzimática , Estabilidade Enzimática , Precipitação Fracionada , Reprodutibilidade dos Testes , Solventes
3.
Sci Rep ; 11(1): 13428, 2021 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-34183749

RESUMO

In this paper, a novel nanocomposite based on magnetic nanoparticles decorated by dopamine were reported. Three modified magnetic nanocomposites by dopamine were offered with different type of linkers. The mentioned magnetic nanocomposites were applied to separate α-amylase protein from fresh bovine milk. All of the magnetic nanocomposites were characterized and investigated by using Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, field-emission scanning microscope, X-ray diffraction pattern, and vibrating-sample magnetometer analyses. To investigate the purifying application, sodium dodecyl sulfate polyacrylamide gel electrophoresis, one-dimensional isoelectric focusing gel electrophoresis, and alpha-amylase activity assay were employed. With paying attention to factors such as yield of purification and concentration of separated protein by each of magnetic nanocomposite, it could be concluded that the length of linkers played an important role in α-amylase protein separation. According to the results, the best separation and purification of α-amylase protein with 49.83% recovery and 40.11-fold purification efficiency was related to longest length linker, 1,4-butanediol diglycidyl ether, because of considerable conjugation with nanocomposite. Also, docking calculation has shown that the binding energy is - 1.697 kcal/mol and ΔG = - 6.844 kcal/mol which result that the interaction process between dopamine and α-amylase protein is spontaneous.


Assuntos
Bovinos/metabolismo , Dopamina/química , Eletroforese em Gel de Poliacrilamida/métodos , Focalização Isoelétrica/métodos , Nanopartículas de Magnetita/química , Leite/enzimologia , Nanocompostos/química , alfa-Amilases/isolamento & purificação , Animais , Feminino , Magnetometria , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
4.
Arch Microbiol ; 203(6): 3641-3655, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33993325

RESUMO

A novel pH and thermo-tolerate halophilic alpha-amylase from moderately halophilic bacterium, Nesterenkonia sp.strain F was cloned and expressed in Escherichia coli. 16S rRNA sequence of the strain shared 99.46% similarities with closely related type species. Also, the genome sequence shared ANI values below 92% and dDDH values below 52% with the closely related type species. Consequently, it is proposed that strain F represents a novel species. The AmyF gene was 1390 bp long and encodes an alpha-amylase of 463 amino acid residues with pI of 4.62. The deduced AmyF shared very low sequence similarity (< 24%) with functionally characterized recombinant halophilic alpha-amylases. The recombinant alpha-amylase was successfully purified from Ni-NTA columns with a molecular mass of about 52 KDa on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme was active over a wide range of temperature (25-75 °C) and pH (4-9) with optimum activity at 45 °C and 7.5, respectively. Also, although it was active over a various concentrations of NaCl and KCl (0-4 M), increasing activity of the enzyme was observed with increasing concentration of these salts. Low concentrations of Ca2+ ion had no activating effect, but high concentrations of the ion (40-200 mM) enhanced activity of AmyF. The enzyme activity was increased by increasing concentrations of Mg2+, Zn2+, Hg2+ and Fe3+. However, it was inhibited only at very high concentrations of these metal ions. Cu2+ did not decrease the amylase activity and the highest activity was observed at 100 mM of the ion. These properties indicate wide potential applications of this recombinant enzyme in starch processing industries. This is the first isolation, cloning and characterization of a gene encoding alpha-amylase from Nesternkonia genus.


Assuntos
Clonagem Molecular , Micrococcaceae/enzimologia , alfa-Amilases/genética , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Proteínas Recombinantes/isolamento & purificação , Termotolerância , alfa-Amilases/química , alfa-Amilases/isolamento & purificação
5.
Microb Cell Fact ; 20(1): 80, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33827572

RESUMO

BACKGROUND: Daqu is the most important fermentation starter for Chinese liquor, with large number of microbes and enzymes being openly enriched in the Daqu system over thousands of years. However, only a few enzymes have been analyzed with crude protein for total liquefying power and saccharifying power of Daqu. Therefore, the complex enzymatic system present in Daqu has not been completely characterized. Moreover, their pivotal and complicated functions in Daqu are completely unknown. RESULTS: In this study, a novel α-amylase NFAmy13B, from GH13_5 subfamily (according to the Carbohydrate-Active enZYmes Database, CAZy) was successfully heterologous expressed by Escherichia coli from Chinese Nong-flavor (NF) Daqu. It exhibited high stability ranging from pH 5.5 to 12.5, and higher specific activity, compared to other GH13_5 fungal α-amylases. Moreover, NFAmy13B did not show activity loss and retained 96% residual activity after pre-incubation at pH 11 for 21 h and pH 12 for 10 h, respectively. Additionally, 1.25 mM Ca2+ significantly improved its thermostability. NFAmy13B showed a synergistic effect on degrading wheat starch with NFAmy13A (GH13_1), another α-amylase from Daqu. Both enzymes could cleave maltotetraose and maltopentaose in same degradation pattern, and only NFAmy13A could efficiently degrade maltotriose. Moreover, NFAmy13B showed higher catalytic efficiency on long-chain starch, while NFAmy13A had higher catalytic efficiency on short-chain maltooligosaccharides. Their different catalytic efficiencies on starch and maltooligosaccharides may be caused by their discrepant substrate-binding region. CONCLUSIONS: This study mined a novel GH13_5 fungal α-amylase (NFAmy13B) with outstanding alkali resistance from Nong-flavor (NF) Daqu. Furthermore, its synergistic effect with NFAmy13A (GH13_1) on hydrolyzing wheat starch was confirmed, and their possible contribution in NF Daqu was also speculated. Thus, we not only provide a candidate α-amylase for industry, but also a useful strategy for further studying the interactions in the complex enzyme system of Daqu.


Assuntos
Bebidas Alcoólicas/microbiologia , Fungos/enzimologia , alfa-Amilases/isolamento & purificação , Hidrólise , Amido/metabolismo
6.
Int J Biol Macromol ; 169: 228-238, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33338531

RESUMO

Robust amylases with stability and catalysis at multitude of extremities are the need of an hour. Enzyme immobilization may prove beneficial at commercial scale to achieve such attributes. In the present study, a commercially available amylase was immobilized on graphene oxide (GO) - magnetite (Fe3O4) nanoparticles through covalent bonding. The structural and morphological characterizations were conducted by XRD, SEM and TEM. Further, FTIR and TGA confirmed the interaction between amylase, GO and nanoparticles. The variables, such as concentrations of GO (1.3 mg), Fe3O4 (58 µg), and amylase (4.5 mg) were optimized by the response surface methodology using central composite design. High loading capacity of 77.58 µg amylase over 1 µg GO-magnetite nanoparticles was achieved under optimum conditions. Biochemically, the pH optimum remained unaltered, i.e., pH 7, whereas, the alkalitolerance was increased by ~20% in relative activities upon immobilization. The half-life of soluble amylase was 13 h, which enhanced to 20 h upon immobilization in 20 mM phosphate buffer, pH 7 at 50 °C. Besides, the thermodynamic parameters supported the stability trends. The immobilized amylase could be used for 11 subsequent cycles. The mentioned attributes and the dextrose equivalent values during the production of high maltose containing syrup highlighted its commercialization.


Assuntos
Nanopartículas de Magnetita/química , Maltose/química , alfa-Amilases/isolamento & purificação , Amilases/química , Biocatálise , Estabilidade Enzimática , Enzimas Imobilizadas/química , Grafite/química , Concentração de Íons de Hidrogênio , Cinética , Temperatura , Termodinâmica , alfa-Amilases/química , beta-Amilase/química
7.
Int J Biol Macromol ; 167: 1102-1112, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33188814

RESUMO

Efficient resource utilization plays a central role in the high productivity of domesticated plants and animals. Whether artificial selection acts on digestive enzymes in the domesticated silkworm (Bombyx mori), which is larger than its wild ancestor, Bombyx mandarina (B. mandarina), remains unknown. In this study, we present the characteristics of a novel alpha-amylase, BmAmy1, in B. mori. The activity of recombinant BmAmy1 was maximal at 35 °C and pH 9.0, and could be suppressed by amylase inhibitors from mulberry, the exclusive food source of silkworms. Three different transposable element fragments, which were independently inserted in the 5'-upstream regulatory region, might be responsible for the enhanced expression of BmAmy1 in different domesticated silkworm strains as revealed by dual-luciferase reporter assay. The BmAmy1 overexpression increased the weight of female and male B. mori by 11.9% and 6.8%, respectively, compared with non-transgenic controls. Our results emphasize that, by exploring the genetic mechanisms of human-selected traits, the domestication process could be further accelerated through genetic engineering and targeted breeding.


Assuntos
Bombyx/enzimologia , Domesticação , Seleção Genética , alfa-Amilases/química , alfa-Amilases/metabolismo , Animais , Bombyx/anatomia & histologia , Bombyx/classificação , Bombyx/genética , Clonagem Molecular , Biologia Computacional/métodos , Elementos de DNA Transponíveis , Ativação Enzimática , Evolução Molecular , Feminino , Expressão Gênica , Genes Reporter , Vetores Genéticos/genética , Proteínas de Insetos/química , Proteínas de Insetos/genética , Proteínas de Insetos/isolamento & purificação , Proteínas de Insetos/metabolismo , Masculino , Fenótipo , Filogenia , alfa-Amilases/genética , alfa-Amilases/isolamento & purificação
8.
Int J Biol Macromol ; 167: 279-288, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33275969

RESUMO

α-Amylase inhibitors (α-AIs) delay digestion of dietary starch by inhibiting α-amylase in the gut, thereby reducing the postprandial glycemia, which is beneficial to the patients with obesity and diabetes. The proteinaceous α-AIs from wheat can effectively control starch digestion and regulate postprandial hyperglycemia. However, their gastric intolerance remains a challenge, which limits its commercial production and industrial application. In this study, sodium alginate/chitosan aerogels loaded with wheat protein α-AIs were prepared and evaluated as potential transportation and protection matrices for important components in food or pharmaceutical applications. Specifically, the biodegradable aerogel cross-linked with sodium alginate-chitosan-calcium chloride, has a large surface area and open porous structure, which can adsorb staple wheat proteins as an integrated edible material to block around 88,660 U/g of α-amylase activity. The aerogel particles were able to protect the activity of wheat α-AIs in the stomach, leading to the slow passage of the wheat α-AIs through the small intestine to inhibit starch digestion more effectively. Animal experiments further showed that the postprandial blood glucose levels in rats were effectively controlled through delayed increase, after administration of wheat protein-functionalized aerogel particles loaded with wheat α-AIs, which are natural biological macromolecules. This is a novel, safe, and economical method for the prevention and pretreatment of diabetes.


Assuntos
Produtos Biológicos/química , Produtos Biológicos/farmacologia , Géis/química , Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Proteínas de Vegetais Comestíveis/química , Proteínas de Vegetais Comestíveis/farmacologia , Administração Oral , Produtos Biológicos/isolamento & purificação , Glicemia , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática , Hiperglicemia/sangue , Hiperglicemia/tratamento farmacológico , Hipoglicemiantes/isolamento & purificação , Proteínas de Vegetais Comestíveis/isolamento & purificação , Triticum/química , Triticum/enzimologia , alfa-Amilases/antagonistas & inibidores , alfa-Amilases/química , alfa-Amilases/isolamento & purificação
9.
Int J Biol Macromol ; 168: 350-355, 2021 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-33310101

RESUMO

Colorado potato beetle is an invasive insect herbivore and one of the most challenging agricultural pests globally. This study is the first characterization of the active centre of Colorado potato beetle (Leptinotarsa decemlineata) α-amylase (LdAmy). Bond cleavage frequency values for LdAmy were determined by HPLC product analysis on a chromophore labelled maltooligomer substrate series. Binding energies between amino acid moieties of subsites and glucose residues of substrate were calculated. Active site contains six subsites in the binding region of LdAmy; four glycone- (-4, -3, -2, -1) and two aglycone-binding sites (+1, +2). Subsite map calculation resulted in apparent binding energies -11.8 and - 11.0 kJ/mol for subsites (+2) and (-3), respectively, which revealed very favorable interactions at these positions. Structures of binding sites of LdAmy and mammalian α-amylases show similarity, but there are variations in the binding energies at subsite (-2) and (-4). Differences were interpreted by comparison of amino acid sequences of human salivary α-amylase (HSA) and porcine pancreatic α-amylase (PPA) and two insect (Leptinotarsa decemlineata and Tenebrio molitor) enzymes. The observed substitution of positively charged His305 in HSA at subsite (-2) with an acidic Asp in LdAmy in the same position may explain the obtained energy reduction.


Assuntos
Besouros/enzimologia , alfa-Amilases/isolamento & purificação , alfa-Amilases/metabolismo , Sequência de Aminoácidos/genética , Animais , Sítios de Ligação/genética , Domínio Catalítico/genética , Besouros/metabolismo , Humanos , Hidrólise , Ligação Proteica/genética , Homologia de Sequência de Aminoácidos , Especificidade por Substrato/genética , Suínos/genética , Tenebrio/genética , alfa-Amilases/genética
10.
Int J Biol Macromol ; 164: 3332-3339, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32871125

RESUMO

Alpha-amylase producing strain KB 2216 was identified as Bacillus velezensis. The growth pattern showed that 72 h is the optimum incubation period of amylase production, which is a stationary period for the strain. By the purification process, maximum alpha-amylase activity was achieved up to 418.25 U/mL at 72 h of incubation, which was purified with 4.74 folds, 4230.32 U/mg specific activity, with 31.35% yield. The strain was found to produce an oligomeric alpha-amylase, namely Amy3. Amy3 was a trimeric macromolecule of 195 kDa with 62, 64, and 66 kDa subunits, as revealed by zymogram and SDS PAGE analyses. Amy3 was highly active at 55 °C and pH 5.5. It had shown the highest stability at pH 5.0-5.5 and between 0 ̊C and 4 ̊C. It did not require any metal cofactors, but it was inhibited by Ag2+, Hg2+ and Cd2+ divalent cations. Glucose and maltose were shown to be the end products of soluble starch digestion by Amy3. These interesting properties of Amy3 may be useful for many biotechnological applications in the future.


Assuntos
Bacillus/metabolismo , alfa-Amilases/química , alfa-Amilases/isolamento & purificação , Bacillus/química , Bacillus/enzimologia , Eletroforese em Gel de Poliacrilamida/métodos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Maltose , Peso Molecular , Amido , Temperatura , alfa-Amilases/metabolismo
11.
Int J Biol Macromol ; 163: 2415-2428, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32961188

RESUMO

The present study deals with the genetic changes observed in the protein sequence of an α-amylase from Streptomyces spp. and its structural homologs from Pseudoalteromonas haloplanktis, invertebrates and mammals. The structural homologs are renowned for their important features such as chloride binding triad and a serine-protease like catalytic triad (a triad which is reported to be strictly conserved in all chloride-dependent α-amylases). These conserved regions are essential for allosteric activation of enzyme and conformational stability, respectively. An evaluation of these distinctive features in Streptomyces α-amylases revealed the role of mutations in conserved regions and evolution of chloride-independent α-amylases in Streptomyces spp. Besides, the study also discovers a highly divergent α-amylase from Streptomyces spp. which varies greatly even within the homologs of the same genus. Another very important feature is the number of disulfide bridges in which the structural homologs own eight Cys residues to form four disulfide bridges whereas Streptomyces α-amylases possess only seven Cys to form three disulfide bridges. The study also highlights the unique evolution of carbohydrate binding module 20 domain (CBM20 also known as raw starch binding domain or E domain) in Streptomyces α-amylases which is completely absent in α-amylases of other structural homologs.


Assuntos
Pseudoalteromonas/enzimologia , Streptomyces/enzimologia , Homologia Estrutural de Proteína , alfa-Amilases/ultraestrutura , Sequência de Aminoácidos/genética , Catálise , Dissulfetos/química , Conformação Proteica , alfa-Amilases/química , alfa-Amilases/genética , alfa-Amilases/isolamento & purificação
12.
Int J Biol Macromol ; 160: 944-952, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32464199

RESUMO

In this study, Arabian balsam α-amylase was purified using the three-step purification method with 9.8-fold purification and 7% recovery. The purified α-amylase's molecular weight was 85 kDa. Calcium alginate incorporated with iron (III) oxide nanoparticles was applied as an immobilizing support for α-amylase. The immobilized α-amylase was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. In addition, the optimum conditions for immobilization efficiency, immobilization time, reusability, kinetic parameters, and the effect of pH for the immobilization process were examined. After storage, about 87% of the initial activity was maintained at 4 °C for 60 days. The immobilized enzyme exhibited enhanced stability compared to the soluble enzyme in relation to pH and temperature. The immobilized enzyme provided the following kinetic variables: 0.455 mg/mL, 4050 s-1, 28.57 µmol maltose/mL, and 8900 s-1 mg-1 mL for Km, kcat, Vmax, and kcat/Km, respectively, compared with 1.798 mg/mL, 5980 s-1, 42.19 µmol maltose/mL, and 3326 s-1 mg-1 mL for the soluble enzyme. The total phenolic contents of the soluble and immobilized α-amylase-treated wheat kernels were increased by 1.26 and 1.31 fold, respectively. Purified α-amylase from Arabian balsam can thus be successfully used to enhance the antioxidant capacity of cereals.


Assuntos
Alginatos/química , Bálsamos/química , Enzimas Imobilizadas , Nanopartículas de Magnetita/química , alfa-Amilases/química , Fracionamento Químico , Composição de Medicamentos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Peso Molecular , Nanocompostos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria , alfa-Amilases/isolamento & purificação
13.
Mar Biotechnol (NY) ; 22(3): 403-410, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32172475

RESUMO

Halophilic bacteria are well known to produce highly salt-tolerant enzymes that have unusual applications in biotechnology. Production of halophilic proteins is generally not expected in mesohaline microorganisms. Ulkenia sp. AH-2, a mesohaline, marine straminipilan thraustochytrid isolated from waters of a mangrove ecosystem, produces halophilic alpha-amylases. Four enzyme fractions, viz.., A, B, C, and D, were obtained upon ammonium sulfate fractionation and gel filtration. These had a broad salinity tolerance ranging from 0 to 4 M NaCl, with an optimum at 3 M NaCl. Pools A, C, and D each resolved as a single band on PAGE and zymogram analysis, and the purified proteins were designated Amy a, Amy c, and Amy h. The major activity resided in "pool B," consisting of several amylases which could not be further resolved into pure fractions. Together, these had an optimum at 2 M NaCl. All the enzymes were stable to storage for 2 to 24 h at 4 °C in a range of salt concentrations and even showed enhanced activity following such incubations. True to halophilic enzymes, the complex of "pool B" amylases showed improved activity in the presence of a wide range of organic solvents at 20% concentration. These enzymes are of particular interest by virtue of their constitutive nature as well as production under culture conditions that do not require salinity beyond that of seawater.


Assuntos
Estramenópilas/enzimologia , alfa-Amilases/isolamento & purificação , alfa-Amilases/metabolismo , Estabilidade Enzimática , Salinidade , Solventes/farmacologia , alfa-Amilases/química
14.
Curr Pharm Biotechnol ; 21(9): 872-881, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32000641

RESUMO

OBJECTIVE: Amylases enzymes hydrolyze starch molecules to produce diverse products including dextrins, and progressively smaller polymers. These include glucose units linked through α-1- 1, α-1-4, α-1-6, glycosidic bonds. METHODS: This enzyme carrying an (α /ß) 8 or TIM barrel structure is also produced containing the catalytic site residues. These groups of enzymes possess four conserved regions in their primary sequence. In the Carbohydrate-Degrading Enzyme (CAZy) database, α-amylases are classified into different Glycoside Hydrolase Families (GHF) based on their amino acid sequence. The present objective was to study one such enzyme based on its molecular characterization after purification in our laboratory. Its main property of solid-natural starch degradation was extensively investigated for its pharmaceutical/ industrial applications. RESULTS: Amylase producing bacteria Bacillus cereus sm-sr14 (Accession no. KM251578.1) was purified to homogeneity on a Seralose 6B-150 gel-matrix and gave a single peak during HPLC. MALDITOF mass-spectrometry with bioinformatics studies revealed its significant similarity to α/ß hydrolase family. The enzyme showed an efficient application; favourable Km, Vmax and Kcat during the catalysis of different natural solid starch materials. Analysis for hydrolytic product showed that this enzyme can be classified as the exo-amylase asit produced a significant amount of glucose. CONCLUSION: Besides the purified enzyme, the present organism Bacillus cereus sm-sr14 could degrade natural solid starch materials like potato and rice up to the application level in the pharmaceutical/ industrial field for alcohol production.


Assuntos
Bacillus cereus/enzimologia , Etanol/metabolismo , Amido/metabolismo , alfa-Amilases/isolamento & purificação , alfa-Amilases/metabolismo , Sequência de Aminoácidos , Biotecnologia , Estabilidade Enzimática , Preparações Farmacêuticas , Especificidade por Substrato
15.
Protein Expr Purif ; 170: 105609, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32070765

RESUMO

Brown-rot fungi preferentially degrade softwood and cause severe breakdown of wooden structures. At the initial stage of the brown-rot decay, penetrating hyphae of the fungi are observed in ray parenchyma. Since starch grains are known to be present in the ray parenchyma of sapwood, investigation of the functions and roles of the starch-degrading enzymes is important to understand the initial stage of brown-rot decay. We purified and characterized two starch-degrading enzymes, an α-amylase (FpAmy13A) and a glucoamylase (FpGLA15A), from the brown-rot fungus, Fomitopsis palustris, and cloned the corresponding genes. The optimal temperature for both enzymes was 60 °C. FpAmy13A showed higher activity at a broad range of pH from 2.0 to 5.0, whereas FpGLA15A was most active at pH 5.0-6.0. Notable thermal stability was found for FpGLA15A. Approximately 25% of the activity remained even after treatment at 100 °C for 30 min in sodium phosphate buffer at pH 7.0. These different characteristics imply the different roles of these enzymes in the starch degradation of wood.


Assuntos
Coriolaceae/enzimologia , Proteínas Fúngicas/metabolismo , Glucana 1,4-alfa-Glucosidase/metabolismo , Proteínas Recombinantes/metabolismo , Amido/metabolismo , alfa-Amilases/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Coriolaceae/química , Coriolaceae/genética , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/isolamento & purificação , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Glucana 1,4-alfa-Glucosidase/genética , Glucana 1,4-alfa-Glucosidase/isolamento & purificação , Concentração de Íons de Hidrogênio , Hidrólise , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Amido/química , Temperatura , Madeira/microbiologia , alfa-Amilases/genética , alfa-Amilases/isolamento & purificação
16.
Int J Biol Macromol ; 145: 325-331, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31843609

RESUMO

Structural modification of starch using efficient α-amylases to improve its properties is an established method in the starch industry. In our previous research, the novel maltogenic α-amylase CoMA that catalyzes multi-molecular reactions has been identified. In this study, the impact of CoMA on the structure and retrogradation properties of potato starch was evaluated. CoMA cleaves internal starch chains to change the proportion of amylose and amylopectin in starch. Following treatment, visible pores and microporous on the surface of starch granules were observed from SEM analysis. CoMA modification led to increased insoluble blue complex formation and hydrolysis to shorten the outer chains, which was found to reduce the development rate of starch according to network interactions from the dynamic rheological analysis. Furthermore, maltose accumulation with water competition was also deduced to be involved in the inhibition of retrogradation. Its activities in the cleavage of internal starch granules, shortening of outer chains of starch, and maltose formation make CoMA a powerful agent for the inhibition of starch retrogradation with a very low effective dose of 0.5 mg/kg, which may find potential applications in the starch processing industry.


Assuntos
Proteínas de Bactérias/química , Solanum tuberosum/química , Amido/química , alfa-Amilases/química , Proteínas de Bactérias/isolamento & purificação , Tecnologia de Alimentos/métodos , Humanos , Hidrólise , Maltose/química , Myxococcales/química , Myxococcales/enzimologia , Porosidade , Solubilidade , Amido/isolamento & purificação , Água/química , alfa-Amilases/isolamento & purificação
17.
Int J Biol Macromol ; 145: 804-812, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31758985

RESUMO

An alkaliphile bacterial strain designated as CH11 was isolated from the sediments of Chilika Lake, Odisha. The isolate showed stupendous growth and production of α-amylase at pH 10.0. Through 16S rRNA gene based molecular technique this isolate was identified as Bacillus cereus strain SP-CH11 having GenBank Accession No. KT992791. Homogenous ~55 kDa extracellular α-amylase was extracted with 241.304, 26.26 and 3.2-fold acceleration in specific activity, purification fold and yield respectively. The alkaline α-amylase AA11 was further characterized. At pH 9.0 the purified enzyme AA11 was highly stable while retaining 88-100% functional viability at temperature range from 35 to 65 °C, confirming its thermostability nature. It showed stability with powdered and liquid detergents at 7 mg/mL and 100-fold dilutions respectively. AA11 efficiently removed the starch stain from cotton fabrics. The findings of this study indicate that the isolate CH11 is a source of novel alkaline α-amylase that has promising application in food and detergent industries.


Assuntos
Bacillus cereus/enzimologia , alfa-Amilases/biossíntese , alfa-Amilases/química , Bacillus cereus/genética , Bacillus cereus/isolamento & purificação , Sequência de Bases , Fenômenos Químicos , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Cinética , Lagos , Peso Molecular , Conformação de Ácido Nucleico , Filogenia , Temperatura , Microbiologia da Água , alfa-Amilases/genética , alfa-Amilases/isolamento & purificação
18.
Appl Microbiol Biotechnol ; 104(2): 643-652, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31788710

RESUMO

Immobilization of the enzyme benefits the catalytic industry a lot. The gram-positive enhancer matrix (GEM) particles could purify and immobilize the recombinant α-amylase in one step without changing the enzymatic character. The enzyme immobilized by GEM particles exhibited good reusability and storage stability. The denaturants dissolved some of the GEM particles and a part of the GEM particles could bear the denaturants. The GEM particles had strong binding ability to the recombination protein with the AcmA tag even when the denaturants existed. The inclusion body was dissolved by urea and then bound by the GEM particles. The GEM particles binding the recombination protein were separated by centrifugation and resuspended in the renaturation solution. GEM particles were recycled by repeating the boiling procedure used in preparing them. The recombination α-amylase without any tag was obtained by digestion and separated via centrifugation. Altogether, our findings suggest that GEM particles have the potential to function as both immobilization and purification materials to bind the soluble recombinant protein with the AcmA tag and the inclusion body dissolved in the denaturants.


Assuntos
Enzimas Imobilizadas/isolamento & purificação , Corpos de Inclusão/enzimologia , Proteínas Recombinantes/isolamento & purificação , alfa-Amilases/isolamento & purificação , Estabilidade Enzimática , Escherichia coli/enzimologia , Ligação Proteica
19.
Protein J ; 38(6): 716-722, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31562586

RESUMO

α-Amylases are used in various biotechnological processes including the textile, paper, food, biofuels, detergents and pharmaceutical industries. In this study, a novel gene encoding α-amylase was cloned from marine bacterium Salinispora arenicola CNP193 and the protein was expressed in Escherichia coli. The α-amylase gene from S. arenicola CNP193 had a length of 1839 bp and encoded a α-amylase with an estimated molecular mass of 74 kDa. The optimum temperature and pH for the recombinant α-amylase was 50 °C and 7 respectively. Na+, K+ and Ca2+ increased the activity of the recombinant α-amylase whereas the enzyme was inhibited by Cu2+, Zn2+, Hg2+, Pb2+, Fe3+ and Mn2+. Thin layer chromatography results confirmed that monosaccharide, disaccharide and maltotriose are the hydrolysis products. The results of our study suggest that this enzyme has considerable potential in industrial applications.


Assuntos
Micromonosporaceae/enzimologia , Proteínas Recombinantes/química , alfa-Amilases , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Clonagem Molecular , Escherichia coli , Cinética , alfa-Amilases/química , alfa-Amilases/genética , alfa-Amilases/isolamento & purificação
20.
Int J Biol Macromol ; 140: 833-841, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445154

RESUMO

Industrial enzymes such as α-amylase must be thermostable and also easily purified/concentrated. Hence, aqueous two-phase partitioning systems (ATPS) was exploited for the partitioning of α-amylase from Aureobasidium pullulans due to its numerous advantages over conventional purification strategy. A. pullulans α-amylase was partially purified using ATPS via response surface methodology (RSM). The potentials of the ATPS-purified enzyme for possible industrial application such as resistance to thermal inactivation was investigated in comparison with the crude enzyme. PEG-6000 was the polymer of choice for ATPS as it resulted in higher purification factor (PF), %yield (Y), and partition coefficient (PC). At optimum levels (% w/v) of 20, 12 and 7.5 for PEG-6000, sodium citrate and sodium chloride respectively, maximum PF, Y and PC of 4.2, 88%, and 9.9 respectively were obtained. The response model validation and reliability were established based on the closeness between the experimented and predicted values. The kinetic and thermodynamic parameters such as Q10, t1/2, kd, D - value, Ed, [Formula: see text] [Formula: see text] of the ATPS-purified α-amylase indicated that it was thermostable at 50 to 60 °C compared to the crude α-amylase. A thermodynamically stable and ATPS-purified α-amylase from A. pullulans has properties easily applicable for most industrial processes.


Assuntos
Ascomicetos/enzimologia , Termodinâmica , alfa-Amilases/química , Análise de Variância , Concentração de Íons de Hidrogênio , Cinética , Extração Líquido-Líquido , Peso Molecular , Polietilenoglicóis/química , Temperatura , alfa-Amilases/isolamento & purificação
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