scholarly journals Immobilization of Aspergillus niger F7-02 Lipase in Polysaccharide Hydrogel Beads of Irvingia gabonensis Matrix

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Safaradeen Olateju Kareem ◽  
Olayinka Quadri Adio ◽  
Michael Bamitale Osho
Keyword(s):  
Aspergillus Niger ◽  
Specific Activity ◽  
Temperature Stability ◽  
Relative Activity ◽  
Formaldehyde Solution ◽  
Hydrogel Beads ◽  
Bead Size ◽  
Size Number ◽  
Irvingia Gabonensis ◽  
Activity Yield

The potential of polysaccharide Irvingia gabonensis matrix as enzyme immobilization support was investigated. Lipase of Aspergillus niger F7-02 was immobilized by entrapment using glutaraldehyde as the cross-linking agent and stabilized in ethanolic-formaldehyde solution. The pH and temperature stability and activity yield of the immobilized enzyme were determined. Such parameters as enzyme load, bead size, number of beads, and bead reusability were also optimized. Adequate gel strength to form stabilized beads was achieved at 15.52% (w/v) Irvingia gabonensis powder, 15% (v/v) partially purified lipase, 2.5% (v/v) glutaraldehyde, and 3 : 1 (v/v) ethanolic-formaldehyde solution. There was 3.93-fold purification when the crude enzyme was partially purified in two-step purification using Imarsil and activated charcoal. Optimum lipase activity 75.3 Ug−1 was achieved in 50 mL test solution containing 15 beads of 7 mm bead size. Relative activity 80% was retained at eight repeated cycles. The immobilization process gave activity yield of 59.1% with specific activity of 12.3 Umg−1 and stabilized at optimum pH 4.5 and temperature 55°C. Thus the effectiveness and cost-efficiency of I. gabonensis as a polymer matrix for lipase immobilization have been established.

scholarly journals Production of polygalacturonase by Aspergillus niger BC23 isolated from Irvingia gabonensis (African mango) fruit

2016 ◽  
Vol 70 (6) ◽  
pp. 717-724
Author(s):  
Nwokoro Ogbonnaya ◽  
Eze Chukwuemeka
Keyword(s):  
Enzyme Activity ◽  
Aspergillus Niger ◽  
Enzyme Production ◽  
Carbon Sources ◽  
Orange Peel ◽  
Relative Activity ◽  
Maximum Activity ◽  
Citrus Pectin ◽  
Enzyme Productivity ◽  
Irvingia Gabonensis

Polygalacturonase was produced from Aspergillus niger BC 23 which was isolated from spoiled Irvingia gabonensis fruit. The influence of carbon substrates on enzyme production showed that the medium containing sucrose produced a maximum enzyme yield of 38.5 U/mg protein after 72 h. Enzyme productivity in this medium was much higher than in the medium that contained only citrus pectin as the sole carbon source. Medium containing yeast extract as a nitrogen source caused the production of specific enzyme activity of 31.2 U/mg protein. Results on the effect of metal ions on enzyme activity showed that Ca2+ gave a percent relative activity of 214% in comparison to the native enzyme activity. The enzyme showed maximum activity in slight acid and neutral pH media with optimal activity at pH 4.0. Temperature activity profile of the enzyme showed best activity at a temperature of 35?C. Dried fruit peels were tested for their abilities to support enzyme production in a media devoid of citrus pectin. The best enzyme productivity of 102.3 U/mg protein was achieved after 72 h in the medium containing orange peel and this level was much higher than that achieved when pure carbon sources or citrus pectin alone were used for enzyme production.

Temperature stability of proteins essential for the intracellular survival of Mycobacterium tuberculosis

2009 ◽  
Vol 418 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Nathan A. Lack ◽  
Akane Kawamura ◽  
Elizabeth Fullam ◽  
Nicola Laurieri ◽  
Stacey Beard ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cholesterol Metabolism ◽  
Specific Activity ◽  
Temperature Stability ◽  
Heat Stability ◽  
Dienoic Acid ◽  
Dramatic Reduction ◽  
Acid Hydrolase ◽  
Catabolic Pathway

In Mycobacterium tuberculosis, the genes hsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) and nat (arylamine N-acetyltransferase) are essential for survival inside of host macrophages. These genes act as an operon and have been suggested to be involved in cholesterol metabolism. However, the role of NAT in this catabolic pathway has not been determined. In an effort to better understand the function of these proteins, we have expressed, purified and characterized TBNAT (NAT from M. tuberculosis) and HsaD (2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid hydrolase) from M. tuberculosis. Both proteins demonstrated remarkable heat stability with TBNAT and HsaD retaining >95% of their activity after incubation at 60 °C for 30 min. The first and second domains of TBNAT were demonstrated to be very important to the heat stability of the protein, as the transfer of these domains caused a dramatic reduction in the heat stability. The specific activity of TBNAT was tested against a broad range of acyl-CoA cofactors using hydralazine as a substrate. TBNAT was found to be able to utilize not just acetyl-CoA, but also n-propionyl-CoA and acetoacetyl-CoA, although at a lower rate. As propionyl-CoA is a product of cholesterol catabolism, we propose that NAT could have a role in the utilization of this important cofactor.

scholarly journals Purification and Characterization of Endoglucanase from local isolate of Aspergillus flavus

2013 ◽  
Vol 10 (3) ◽  
pp. 844-853
Author(s):  
Baghdad Science Journal
Keyword(s):  
Aspergillus Flavus ◽  
Specific Activity ◽  
Gel Filtration ◽  
Temperature Stability ◽  
Exchange Chromatography ◽  
Purification And Characterization ◽  
Original Activity ◽  
A Value ◽  
Optimum Ph

Endoglucanase produced from Aspergillus flavus was purified by several steps including precipitation with 25 % ammonium sulphate followed by Ion –exchange chromatography, the obtained specific activity was 377.35 U/ mg protein, with a yield of 51.32 % .This step was followed by gel filtration chromatography (Sepharose -6B), when a value of specific activity was 400 U/ mg protein, with a yield of 48 %. Certain properties of this purified enzyme were investigated, the optimum pH of activity was 7 and the pH of its stability was 4.5, while the temperature stability was 40 °C for 60 min. The enzyme retained 100% of its original activity after incubation at 40 °C for 60 min; the optimum temperature for enzyme activity was 40 °C.

Phosphatidylethanolamine in Liver Mitochondria and Endoplasmic Reticulum; Molecular Species Distribution and Turnover

1975 ◽  
Vol 53 (6) ◽  
pp. 698-705 ◽  
Author(s):  
J. G. Parkes ◽  
W. Thompson
Keyword(s):  
Endoplasmic Reticulum ◽  
Fatty Acid ◽  
Specific Activity ◽  
Liver Mitochondria ◽  
Relative Activity ◽  
Layer Chromatography ◽  
Kinetics Of ◽  
Fatty Acid Compositions

Phosphatidylethanolamine from mitochondria and microsomes of guinea pig liver was separated by thin-layer chromatography into eight different classes differing in degree of unsaturation. The fatty acid compositions and molar proportions of each class isolated from microsomes were very similar to the corresponding class in mitochondria. In both organelles about half of the total was dienoic species while tetraenes comprised approximately 20%. Stearic acid was the major saturated fatty acid and in each membrane a greater selectivity for stearate over palmitate was found in each sub-class of phosphatidylethanolamine, when compared with the corresponding class of phosphatidylcholine.Following the intraperitoneal injection of [2-3H]glycerol, the labelling of each molecular class of phosphatidylethanolamine showed very similar progressions in microsomes and mitochondria over a 3 h interval. In both organelles the highest relative specific activity was attained by penta-plus hexaenoic classes, while the large dienoic class had the lowest relative activity, which, however, increased with time. Analysis of the dienoic class of phosphatidylethanolamine from whole liver showed it to be constituted by a rapidly turning over palmitoyl–linoleoyl fraction and a slowly labelled stearoyl–linoleoyl fraction, a pattern also exhibited by dienoic phosphatidylcholines.The similarities in profile of molecular classes of phosphatidylethanolamine and in the kinetics of labelling in vivo point to a close metabolic relation between the lipids of both organelles, suggestive of a transfer of different molecular classes at comparable rates from the endoplasmic reticulum, the site of synthesis, to the mitochondria. This is consistent with numerous other studies in vitro that have demonstrated inter-organelle exchange of lipids.

UDP-Glucose: Flavonol 7-O-glucosyltransferase Activity in Flower Extracts of Chrysanthemum segetum

1997 ◽  
Vol 52 (3-4) ◽  
pp. 153-158 ◽  
Author(s):  
K. Stich ◽  
H. Halbwirth ◽  
F. Wurst ◽  
G. Forkmann
Keyword(s):  
Enzyme Activity ◽  
Specific Activity ◽  
Temperature Stability ◽  
Inhibitory Effect ◽  
Hydroxyl Group ◽  
Ph Optimum ◽  
Yellow Colour ◽  
Commercial Strain ◽  
Strong Inhibitory Effect ◽  
Chrysanthemum Segetum

Abstract The yellow colour of Chrysanthemum segetum petals is due to the presence of the 7-O-glucosides of quercetin and particularly gossypetin (8-hydroxyquercetin). In petal extracts of C. segetum an enzyme was demonstrated which catalyzes the transfer of the glucosyl moiety of uridine 5'-diphosphoglucose (UDPG) to the 7-hydroxyl group of flavonols with gossypetin and quercetin as the best substrates. Besides flavonols flavanones and flavones were found to be glucosylated in the 7-position. The pH-optimum of the reaction highly depended on the substrate used. With quercetin as substrate, maximal enzyme activity occurred at a pH of 8.25 and a temperature of 25 °C, but 7-O-glucosylation also proceeded at low temperatures. Studies on temperature stability revealed, that there was no influence on the glucosylation reaction up to 40 °C. Higher temperatures led to a loss of enzyme activity. Using gossypetin as a substrate a similar course of temperature stability was observed. Addition of Mg2+, Ca2+ and KCN slightly stimulated 7-O-glucosylation, whereas Co2+, Cu2+, Fe2+, Hg2+, p-hydroxymercuribenzoate and N-ethylmaleimide showed a strong inhibitory effect. Additional enzymatic studies were performed with the commercial strain " Stern des Orients" where gossypetin 7-O-glucoside is restricted to the inner parts of the petals. For enzyme extracts from both parts of the petals gossypetin was found to be the most attractive substrate. In comparison to quercetin (133.4 μkat / kg protein) an about three times higher specific activity of the 7-O-glucosyltransferase(s) was determined with gossypetin (382.1 μkat/ kg protein) as substrate, indicating that hydroxylation of quercetin in 8-position to gossypetin precedes 7-O-glucosylation.

scholarly journals Cloning and expression of a chick liver glutathione S-transferase CL 3 subunit with the use of a baculovirus expression system

1992 ◽  
Vol 281 (2) ◽  
pp. 545-551 ◽  
Author(s):  
L H Chang ◽  
J Y Fan ◽  
L F Liu ◽  
S P Tsai ◽  
M F Tam
Keyword(s):  
Specific Activity ◽  
Sequence Similarity ◽  
Expression System ◽  
Baculovirus Expression System ◽  
Relative Activity ◽  
Cloning And Expression ◽  
Glutathione S Transferase ◽  
Sds Page ◽  
Glutathione S Transferases ◽  
A Subunit

Glutathione S-transferase CL 3 subunits purified from 1-day-old-chick livers were digested with Achromobacter proteinase I and the resulting fragments were isolated for amino acid sequence analysis. An oligonucleotide probe was constructed accordingly for cDNA library screening. A cDNA clone of 1342 bases, pGCL301, encoding a protein of 26209 Da was isolated and sequenced. Including conservative substitutions, this protein has 75-79% sequence similarity to other Alpha family glutathione S-transferases. The coding sequence of pGCL301 was inserted into a baculovirus vector for infection of Spodoptera frugiperda (SF9) cells. The expressed protein has a high relative activity with ethacrynic acid (47% of the specific activity with 1-chloro-2,4-dinitrobenzene). The enzyme has a subunit molecular mass of 25.2 +/- 1.2 kDa (by SDS/PAGE), a pI of 9.45 and an absorption coefficient A1%1cm of 13.0 +/- 0.5 at 280 nm.

scholarly journals Optimization of Processing Parameters for Extraction of Amylase Enzyme from Dragon (Hylocereus polyrhizus) Peel Using Response Surface Methodology

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mehrnoush Amid ◽  
Mohd Yazid Abdul Manap ◽  
Norkhanani Zohdi
Keyword(s):  
Storage Stability ◽  
Specific Activity ◽  
Mixing Time ◽  
Temperature Stability ◽  
Processing Parameters ◽  
Ph Stability ◽  
Extraction Condition ◽  
Main Effect ◽  
And Storage ◽  
Optimum Extraction

The main goal of this study was to investigate the effect of extraction conditions on the enzymatic properties of thermoacidic amylase enzyme derived from dragon peel. The studied extraction variables were the buffer-to-sample (B/S) ratio (1 : 2 to 1 : 6, w/w), temperature (−18°C to 25°), mixing time (60 to 180 seconds), and the pH of the buffer (2.0 to 8.0). The results indicate that the enzyme extraction conditions exhibited the least significant (P<0.05) effect on temperature stability. Conversely, the extraction conditions had the most significant (P<0.05) effect on the specific activity and pH stability. The results also reveal that the main effect of the B/S ratio, followed by its interaction with the pH of the buffer, was significant (P<0.05) among most of the response variables studied. The optimum extraction condition caused the amylase to achieve high enzyme activity (648.4 U), specific activity (14.2 U/mg), temperature stability (88.4%), pH stability (85.2%), surfactant agent stability (87.2%), and storage stability (90.3%).

scholarly journals Shifting the pH Profile of Aspergillus niger PhyA Phytase To Match the Stomach pH Enhances Its Effectiveness as an Animal Feed Additive

2006 ◽  
Vol 72 (6) ◽  
pp. 4397-4403 ◽  
Author(s):  
Taewan Kim ◽  
Edward J. Mullaney ◽  
Jesus M. Porres ◽  
Karl R. Roneker ◽  
Sarah Crowe ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Animal Feed ◽  
Relative Activity ◽  
Feed Additive ◽  
Ph Optimum ◽  
Ph Profile ◽  
Phytate Phosphorus ◽  
Ph Conditions ◽  
Stomach Ph ◽  
Hydrolysis Of

ABSTRACT Environmental pollution by phosphorus from animal waste is a major problem in agriculture because simple-stomached animals, such as swine, poultry, and fish, cannot digest phosphorus (as phytate) present in plant feeds. To alleviate this problem, a phytase from Aspergillus niger PhyA is widely used as a feed additive to hydrolyze phytate-phosphorus. However, it has the lowest relative activity at the pH of the stomach (3.5), where the hydrolysis occurs. Our objective was to shift the pH optima of PhyA to match the stomach condition by substituting amino acids in the substrate-binding site with different charges and polarities. Based on the crystal structure of PhyA, we prepared 21 single or multiple mutants at Q50, K91, K94, E228, D262, K300, and K301 and expressed them in Pichia pastoris yeast. The wild-type (WT) PhyA showed the unique bihump, two-pH-optima profile, whereas 17 mutants lost one pH optimum or shifted the pH optimum from pH 5.5 to the more acidic side. The mutant E228K exhibited the best overall changes, with a shift of pH optimum to 3.8 and 266% greater (P < 0.05) hydrolysis of soy phytate at pH 3.5 than the WT enzyme. The improved efficacy of the enzyme was confirmed in an animal feed trial and was characterized by biochemical analysis of the purified mutant enzymes. In conclusion, it is feasible to improve the function of PhyA phytase under stomach pH conditions by rational protein engineering.

scholarly journals Amylase Production from Solid State Fermentation and Submerged Liquid Fermentation by Aspergillus niger

2012 ◽  
Vol 47 (1) ◽  
pp. 99-104 ◽  
Author(s):  
G Dharani ◽  
NS Kumaran
Keyword(s):  
Solid State ◽  
Aspergillus Niger ◽  
Solid State Fermentation ◽  
Specific Activity ◽  
Basal Medium ◽  
Banana Peel ◽  
Liquid Fermentation ◽  
Cultural Conditions ◽  
Solid Substrates ◽  
Moisture Conditions

The purpose of this work is to study the optimized cultural conditions for the production of amylase by Aspergillus niger in solid state and submerged liquid fermentation. Four solid substrates banana peel, corn, potato and tapioca with different moisture conditions were taken for solid state fermentation (SSF). Basal medium was used for submerged liquid fermentation (SLF) with different pH (3 to 8), temperature (25, 30, 35 and 40ºC), carbon concentration (1, 2 and 3 g) and nitrogen source (0.1, 0.2 and 0.3 g). In SSF, tapioca yielded highest amylase activity and specific activity (4.43U/ml and 4.58U/mg) at 50% moisture content. In SLF, 2 g starch and 0.3 g peptone concentration showed 0.78 and 1.23 U/ml amylase activities under the optimum pH (5) and temperature (30ºC) the amylase activities reached to 0.86 U/ml and 0.76 U/ml respectively. In SSF using tapioca as substrate the enzyme yield is about five times higher than that achieved with submerged liquid culture. DOI: http://dx.doi.org/10.3329/bjsir.v47i1.7310 Bangladesh J. Sci. Ind. Res. 47(1), 99-104, 2012

scholarly journals Biomass of unconventional plants from Brazilian semiarid as substrate for hydrolytic enzymes production by Aspergillus niger under solid and submerged fermentation

2021 ◽  
Vol 43 ◽  
pp. e48257
Author(s):  
Bruna dos Santos Menezes ◽  
Kátia dos Santos Morais ◽  
Aparecido Almeida Conceição ◽  
Juliana Gomes Barreto Souza Leite ◽  
Fábia Giovana do Val de Assis ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Submerged Fermentation ◽  
Hydrolytic Enzymes ◽  
Temperature Stability ◽  
Scaling Up ◽  
Biotechnological Applications ◽  
Cmcase Activity ◽  
Brazilian Semiarid ◽  
Temperature Ranges ◽  
Activity Temperature

Aspergillus niger KIJH was grown in solid and submerged fermentation using leaves and roots (with and without bark) of plants typically from Brazilian semiarid as substrate to produce a multienzymatic extract, which was characterised for its potential biotechnological applications. Solid-state fermentation (SSF) was applied to select the most promising plants biomass as induction substrates for the production of hydrolytic enzymes by fungus. The best biomasses were used as substrate in submerged fermentation (SmF) assays at two scales. Samples of up scale fermented culture were partially purified by ultrafiltration and activity and pH and temperature stability of CMCase and xylanase were evaluated. A. niger KIJH produced hydrolytic enzymes under SSF containing unconventional plants biomass from Brazilian semiarid. In SmF conditions, maximum CMCase (0.264 U mL-1) and xylanase (1.163 U mL-1) activities were induced by Jacaratia corumbensis. Scaling up the SmF to 500 mL of medium was able to maintain constant the production of CMCase (0.346 U mL-1) and xylanase (1.273 U mL-1) on the fermented culture. Ultrafiltered and concentrated extract presented CMCase activities practically constant in all temperature ranges (30-80°C) and pH (3.0-9.0), while xylanase optimum activity temperature was 50°C and pH in the range of 3.0 to 5.0. CMCase activity remained stable for 24 hours at 50°C and xylanase was reduced in 53% after two hours incubation at the same temperature. CMCase and xylanase obtained by A. niger KIJH cultivated in submerged culture containing J. corumbensis as carbon source may have application in biotechnology processes that require enzymes that remain active under routine extreme conditions.

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