scholarly journals Purification and characterization of a novel thermostable β-amylase from Clostridium thermosulphurogenes

1988 ◽  
Vol 254 (3) ◽  
pp. 835-840 ◽  
Author(s):  
G J Shen ◽  
B C Saha ◽  
Y E Lee ◽  
L Bhatnagar ◽  
J G Zeikus

An extracellular beta-amylase from Clostridium thermosulphurogenes was purified 811-fold to homogeneity, and its general molecular, physico-chemical and catalytic properties were determined. The native enzyme was a tetramer of 210 kDa composed of a single type subunit; its 20 amino acid N-terminus displayed 45% homology with Bacillus polymyxa beta-amylase. The beta-amylase was enriched in both acidic and hydrophobic amino acids. The pure enzyme displayed an isoelectric point of 5.1 and a pH activity optimum of 5.5. The optimum temperature for beta-amylase activity was 75 degrees C, and enzyme thermostability at 80 degrees C was enhanced by substrate and Ca2+ addition. The beta-amylase hydrolysed amylose to maltose and amylopectin and glycogen to maltose and limit dextrins, and it was inhibited by alpha- and beta-cyclodextrins. The enzyme displayed kcat. and Km values for boiled soluble starch of 400,000 min-1 per mol and 1.68 mg/ml, respectively. The enzyme was antigenically distinct from plant beta-amylases.

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Imran Ali ◽  
Ali Akbar ◽  
Mohammad Anwar ◽  
Sehanat Prasongsuk ◽  
Pongtharin Lotrakul ◽  
...  

An extracellularα-amylase from the obligate halophilicAspergillus penicillioidesTISTR3639 strain was produced and enriched to apparent homogeneity by ammonium sulfate precipitation and Sephadex G100 gel filtration column chromatography. The mass of the purified amylase was estimated to be 42 kDa by SDS-PAGE. With soluble starch as the substrate it had a specific activity of 118.42 U·mg−1andVmax⁡andKmvalues of 1.05 µmol·min−1·mg−1and 5.41 mg·mL−1, respectively. The enzyme was found to have certain polyextremophilic characteristics, with an optimum activity at pH 9, 80°C, and 300 g·L−1NaCl. The addition of CaCl2at 2 mM was found to slightly enhance the amylase activity, while ZnCl2, FeCl2, or EDTA at 2 mM was strongly or moderately inhibitory, respectively, suggesting the requirement for a (non-Fe2+or Zn2+) divalent cation. The enzyme retained more than 80% of its activity when incubated with three different laundry detergents and had a better performance compared to a commercial amylase and three detergents in the presence of increasing NaCl concentrations up to 300 g·L−1. Accordingly, it has a good potential for use as anα-amylase in a low water activity (high salt concentration) and at high pH and temperatures.


2018 ◽  
Vol 7 (2) ◽  
pp. 33-45
Author(s):  
Mohammad Shahedur Rahman ◽  
Rasheda Banu ◽  
Ripa Moni ◽  
Nazmul Islam ◽  
Mastura Khatun Ruma ◽  
...  

A new isolate was investigated from soil sample collected from Shahrasti upazilla of Chandpur district of Bangladesh. Based on the physico-chemical studies the strain was identified as gram positive Bacilli. Moleculer characterization of the strain was identified as Bacillus aryabhattai which is the first report in Bangladesh. The strain can survive in extreme conditions of salt, temperature and pH. This strain was further characterized and screened for the ability to produce useful enzymes. The optimum temperature for growth and production of these enzymes was within the temperature range 35oC to 40oC. The pH was found to be 7 for its growth and production of different enzymes when investigated over 48 h of incubation. The isolate produced various extracellular enzymes such as α-amylases, cellulases, β-glucosidases, lipases and proteases. The findings of this study provide useful information of the new strain that has potential biotechnological applications. Jahangirnagar University J. Biol. Sci. 7(2): 33-45, 2018 (December)


1986 ◽  
Vol 239 (3) ◽  
pp. 699-704 ◽  
Author(s):  
S Chaudhuri ◽  
J M Lambert ◽  
L A McColl ◽  
J R Coggins

A procedure has been developed for the purification of 3-dehydroquinase from Escherichia coli. Homogeneous enzyme with specific activity 163 units/mg of protein was obtained in 19% overall yield. The subunit Mr estimated from polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate was 29,000. The native Mr, estimated by gel permeation chromatography on Sephacryl S-200 (superfine) and on TSK G3000SW, was in the range 52,000-58,000, indicating that the enzyme is dimeric. The catalytic properties of the enzyme have been determined and shown to be very similar to those of the biosynthetic 3-dehydroquinase component of the arom multifunctional enzyme of Neurospora crassa.


1979 ◽  
Vol 181 (1) ◽  
pp. 183-191 ◽  
Author(s):  
M Castroviejo ◽  
D Tharaud ◽  
L Tarrago-Litvak ◽  
S Litvak

Three DNA polymerases (A, B and C) have been purified from the soluble cytoplasm of ungerminated embryos. Mainly on the basis of chromatographic, template-specificity and salt-inhibition evidence, we have characterized the three enzymes. Other physico-chemical and enzymic properties are described. From purified mitochondria we have purified a DNA polymerase that behaves like DNA polymerase B on chromatographic and template-specificity criteria. Only highly purified enzyme B from the soluble cytoplasm showed an exonuclease activity able to degrade 3′- or 5′-labelled polydeoxyribonucleotides, as well as a ‘proof-reading’ capacity.


1991 ◽  
Vol 279 (1) ◽  
pp. 67-73 ◽  
Author(s):  
U Fauth ◽  
M P M Romaniec ◽  
T Kobayashi ◽  
A L Demain

The extracellular cellulolytic enzymes of the thermophilic anaerobe Clostridium thermocellum occur as a protein complex or aggregate known as the cellulosome. By using a combination of ion-exchange, adsorption and hydrophobic-interaction chromatography, it was possible to isolate from extracellular broth a specific endoglucanase of interest without the use of denaturants. The endoglucanase was identified as the cellulosomal subunit Ss by the use of specific antibodies. The enzyme has an Mr of 83,000, an isoelectric point of 3.55, optimum pH of 6.6 and optimum temperature of 70 degrees C. It hydrolyses CM-cellulose and, at a higher rate, the cellodextrins, cellotetraose and cellopentaose, but does not hydrolyse a crystalline cellulose such as Avicel. Cellobiose and cellotriose are also immune to attack. It differs from endoglucanases previously isolated by others and a 76,000-Mr endoglucanase recently isolated in this laboratory.


2009 ◽  
Vol 4 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Gražina Giedraityte ◽  
Lilija Kalėdienė

AbstractThe purpose of this study was purification and characterization of catechol 1,2-dioxygenase from Geobacillus sp. G27 strain, which degrades α-naphthol by the β-ketoadipate pathway. The catechol 1,2-dioxygenase (C1,2O) was purified using four steps of ammonium sulfate precipitation, DEAE-celullose, Sephadex G-150 and hydroxylapatite chromatographies. The enzyme was purified about 18-fold with a specific activity of 7.42 U mg of protein−1. The relative molecular mass of the native enzyme estimated on gel chromatography of Sephadex G-150 was 96 kDa. The pH and temperature optima for enzyme activity were 7 and 60°C, respectively. A half-life of the catechol 1,2-dioxygenase at the optimum temperature was 40 min. The kinetic parameters of the Geobacillus sp. G27 strain catechol 1,2-dioxygenase were determined. The enzyme had apparent Km of 29 µM for catechol and the cleavage activities for methylcatechols were much less than for catechol and no activity with gentisate or protocatechuate was detected.


2018 ◽  
Vol 23 (1) ◽  
pp. 14 ◽  
Author(s):  
Putri Dwi Mulyani ◽  
Radhiyah Mardhiyah Hamid ◽  
Rifqi Zahroh Janatunaim ◽  
Yekti Asih Purwestri

BSR 2, BSR 3, BSR 8, and BSR 9, different bacteria isolated from the termite gut, have been shown to possess cellulolytic activities, but their amylolytic ability has heretofore been unknown. This study attempted to fill in this knowledge gap. The formation of a clear zone using the iodine test showed that the bacteria were able to produce and secrete amylase. Based on the results, the best cultivation times for strains BSR 2, BSR 3, BSR 8, and BSR 9 were 6, 3, 2, and 2 d, respectively, yielding amylase activities of 2.59 ± 0.13 U/mg, 2.00 ± 0.08 U/mg, 1.67 ± 0.10 U/mg, and 1.55 ± 0.12 U/mg, respectively. BSR 2 had the highest amylase activity compared with the other bacterial isolates. The optimum ph for bacterial amylase activity of BSR 2 was 7.0, and the optimum temperature was 40°C. The molecular characterization of isolates BSR 2, BSR 3, BSR 8, and BSR 9 was based on 16S rRNA gene sequences. Isolates BSR 8 and BSR 9 were thus identified as Brevibacillus parabrevis and Brevibacillus sp. With similarities amounting to 92.48% and 95.91%, while the BSR 3 isolate was identified as Pseudomonas alcaligenes with a similarity of 94.29%, and the BSR 2 isolate could not be identified yet.


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