scholarly journals Free and Immobilised β-Glucosidases in Oenology: Biotechnological Characterisation and Its Effect on Enhancement of Wine Aroma

2021 ◽  
Vol 12 ◽  
Author(s):  
Pilar Fernández-Pacheco ◽  
Beatriz García-Béjar ◽  
Ana Briones Pérez ◽  
María Arévalo-Villena
Keyword(s):  
Volatile Compounds ◽  
Hydrolytic Activity ◽  
Maximum Activity ◽  
Maximum Temperature ◽  
Wine Aroma ◽  
High Concentration ◽  
Aroma Precursors ◽  
Km Value ◽  
Immobilised Enzymes ◽  
Optimal Ph

In grapes, monoterpenes and norisoprenoids are in the form of non-volatile compounds, flavourless glycosides which could enhance the aroma of wines after its hydrolysis using β- glucosidases enzymes. It is known that the use of immobilised enzymes offers advantages such as reusability and easy recuperation. In this study, a commercial β-glucosidase was immobilised by absorption in sodium alginate. Biotechnological characteristics and terpen hydrolysis (hydrolysis aroma precursors) in muscat wines were studied after treatment with both free and immobilised commercial β- glucosidase with two different concentrations. It was revealed that both forms shared an optimal pH (4.5) and a maximum temperature (64°C), even an increment on the activity between 40and 60°C. A similar Km value has been determined while Vmax from the immobilised enzyme was higher than the free (3.35 and 2.52 μmol min–1 mg–1, respectively). Additionally, the immobilised enzyme showed a better hydrolytic activity during 24 h, and its reusability has been proven. Regarding enzymatic hydrolysis in grape must, the best results were observed for the highest concentration of free β-glucosidase although glucose release was also determined for the immobilised enzyme along the days. In contrast, maximum activity was reached by the immobilised β-glucosidase in less time but in no case equalled the free ones. Finally, volatile compound liberation in wines treated with free or immobilised enzymes was analysed using HRGC-MS. Liberation for both enzymes and the greatest concentrations of some volatiles were detected when a double dose of the free β-glucosidase was used. Nevertheless, the wines treated with the immobilised β-glucosidase showed a high concentration of some volatile compounds such as nerol or geraniol.

scholarly journals An inducible hydrolase from Aspergillus niger, acting on carbon–carbon bonds, for phlorrhizin and other C-acylated phenols

1970 ◽  
Vol 116 (5) ◽  
pp. 889-897 ◽  
Author(s):  
T. Minamikawa ◽  
N. P. Jayasankar ◽  
B. A. Bohm ◽  
I. E. P. Taylor ◽  
G. H. N. Towers
Keyword(s):  
Aspergillus Niger ◽  
Metal Ion ◽  
Deae Cellulose ◽  
Hydrolytic Activity ◽  
Maximum Activity ◽  
Protamine Sulphate ◽  
Carbon Carbon Bonds ◽  
Alkaline Conditions ◽  
Km Value ◽  
Ammonium Sulphate Fractionation

1. An inducible enzyme catalysing the hydrolysis of phloretin to form phloroglucinol and phloretic acid has been extracted from the acetone-dried powders of the mycelial felts of an Aspergillus niger strain grown in the presence of phlorrhizin. The enzyme was partially purified by treatment with protamine sulphate, ammonium sulphate fractionation, negative adsorption on tricalcium phosphate gel, and DEAE-cellulose column chromatography. 2. The hydrolytic activity on phloretin appeared to be maximal at about pH9.6. However, the characteristics of the enzyme were studied at pH7.2, because of the lability of the product, phloroglucinol, under alkaline conditions. 3. The apparent Km value at pH7.2 was about 0.3–0.4mm for phloretin and 0.15mm for 3′-methylphloracetophenone. 4. Maximum activity of the enzyme was obtained without the addition of any cofactor or metal ion. The involvement of thiol groups in the reaction was demonstrated by the potent inhibitory action of both heavy-metal ions and p-chloromercuribenzoate. 5. The enzyme showed a rather broad substrate specificity, and some other C-acylated phenols related to phloretin were hydrolysed. It was found that 3′-methylphloracetophenone, phloracetophenone and 2′,4,4′-trihydroxydihydrochalcone were attacked more efficiently than phloretin. We propose the systematic name C-acylphenol acylhydrolase for the enzyme. This enzyme belongs to EC group 3.7.1.

scholarly journals Purification and properties of DNA polymerase from Bacillus caldotenax

1992 ◽  
Vol 287 (3) ◽  
pp. 971-977 ◽  
Author(s):  
J A Burrows ◽  
C R Goward
Keyword(s):  
Enzyme Activity ◽  
Dna Polymerase ◽  
Maximum Activity ◽  
Equimolar Mixture ◽  
High Concentration ◽  
Bivalent Cation ◽  
Absolute Requirement ◽  
Purification And Properties ◽  
Calf Thymus ◽  
Km Value

A thermostable DNA polymerase was prepared from Bacillus caldotenax by using a four-step chromatography procedure. The protein exists as a monomer of M(r) 94,000, has a pI of 4.9 and has no associated 3′-5′ or 5′-3′-exonuclease activities or endonuclease activity. The temperature optimum of the enzyme was about 70 degrees C and the pH for maximum activity was about 7.5. The enzyme has an absolute requirement for a bivalent cation, and maximum activity was obtained at the unusually high concentration of 70 mM-MgCl2. Mg2+ could be replaced by MnCl2 or CoCl2, with decreased activity, at the lower optimal concentrations of 1 mM and 2.5 mM respectively. Enzyme activity was inhibited in the presence of 2′,3′-dideoxy-TTP, arabinosyl-CTP and aphidicolin. Enzyme activity was stimulated with KCl concentrations of about 100 mM, and concentrations of univalent salts above about 150 mM inhibited activity. The enzyme could use activated calf thymus DNA, poly(dA).p(dT)10 or primed single-stranded phage M13 DNA as a template and maximum activity was obtained with poly(dA).p(dT)10. The enzyme was inactive on unprimed single-stranded DNA, double-stranded DNA and polyribonucleotide template/primer. The apparent Km values for individual dNTPs, determined with the other dNTPs at saturating concentrations, were 5.7 microM (dCTP), 6.3 microM (dATP, dGTP) and 6.4 microM (dTTP). The Km value for the overall incorporation of each dNTP from an equimolar mixture of all four dNTPs was 24.7 microM. The kcat. value was about 1.05 s-1. The kcat./Km value was 0.16-0.18 M-1.s-1 for individual dNTPs and 0.04 for the incorporation of an equimolar mixture of all four dNTPs. Some of the properties of the enzyme show it may be classified as an alpha-Type DNA polymerase.

scholarly journals Increase in alkaline phosphatase activity in calvaria cells cultured with diphosphonates

1979 ◽  
Vol 183 (1) ◽  
pp. 73-81 ◽  
Author(s):  
R Felix ◽  
H Fleisch
Keyword(s):  
Alkaline Phosphatase ◽  
Protein Synthesis ◽  
Enzyme Activity ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Heat Inactivation ◽  
High Concentration ◽  
Control Value ◽  
Km Value ◽  
Inhibitor Of Protein Synthesis

1. Dichloromethanediphosphonate and to a lesser degree 1-hydroxyethane-1,1-diphosphonate, two compounds characterized by a P-C-P bond, increased the alkaline phosphatase activity of cultured rat calvaria cells up to 30 times in a dose-dependent fashion. 2. Both diphosphonates also slightly inhibited the protein synthesis in these cells. 3. Thymidine, an inhibitor of cell division, did not inhibit the induction of the enzyme, indicating that the increase in enzyme activity was not due to the formation of a specific population of cells with high alkaline phosphatase activity. 4. The effect on alkaline phosphatase was suppressed by the addition of cycloheximide, an inhibitor of protein synthesis. 5. After subculturing the stimulated cells in medium without diphosphonates, the enzyme activity fell almost to the control value. 6. Bovine parathyrin diminished the enzyme activity of the control cells and the cells treated with dichloromethanediphosphonate; however, at high concentration the effect of parathyrin was greater on the diphosphonate-treated cells than on the control cells. 7. The electrophoretic behaviour, heat inactivation, inhibition by bromotetramisole or by phenylalanine, and the Km value of the induced enzyme were identical with that of the control enzyme.

scholarly journals Purification and characterization of acid phosphatase from a germinating black gram (Vigna mungo L.) seedling

2011 ◽  
Vol 63 (3) ◽  
pp. 747-756 ◽  
Author(s):  
A.K.M. Asaduzzaman ◽  
Habibur Rahman ◽  
Tanzima Yeasmin
Keyword(s):  
Acid Phosphatase ◽  
Gel Electrophoresis ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Inhibitory Effect ◽  
Maximum Activity ◽  
Exchange Chromatography ◽  
Black Gram ◽  
Km Value

An acid phosphatase has been isolated and purified from an extract of a germinating black gram seedling. The method was accomplished by gel filtration of a germinating black gram seedling crude extract on sephadex G-75 followed by ion exchange chromatography on DEAE cellulose. The acid phosphatase gave a single band on SDS-polyacrylamide slab gel electrophoresis. The molecular weight of the acid phosphatase determined by SDS-polyacrylamide slab gel electrophoresis was estimated to be 25 kDa. The purified enzyme showed maximum activity at pH 5 and at temperature of 55?C. Mg2+, Zn2+ and EDTA had an inhibitory effect on the activity of the acid phosphatase. Black gram seedling acid phosphatase was activated by K+, Cu2+ and Ba2+. The Km value of the enzyme was found to be 0.49 mM for pNPP as substrate.

scholarly journals Development of organic acids and volatile compounds in cider during malolactic fermentation

2014 ◽  
Vol 32 (No. 1) ◽  
pp. 69-76 ◽  
Author(s):  
H. Zhao ◽  
F. Zhou ◽  
P. Dziugan ◽  
Y. Yao ◽  
J. Zhang ◽  
...  
Keyword(s):  
Organic Acids ◽  
Volatile Compounds ◽  
Carbonyl Compounds ◽  
Alcoholic Fermentation ◽  
Total Concentration ◽  
Malolactic Fermentation ◽  
High Concentration ◽  
Volatile Acidity ◽  
Organoleptic Characteristics

The effect of malolactic fermentation (MLF) on the flavour quality of cider was examined. Leuconostoc mesenteroides subsp. mesenteroides Z25 was used to start MLF taking place at 25°C for 12 days after the completion of alcoholic fermentation (AF) by Saccharomyces cerevisiae. Strain Z25 showed good activity in starting MLF of cider with 10% alcoholic concentration. The content of malic acid, whose high concentration gives negative organoleptic characteristics to the cider, dropped significantly from 4.0 g/l to 0.25 g/l via MLF. The concentration of lactic acid increased significantly from 0.99 g/l to 3.50 g/l, contributing to volatile acidity. The acetic acid content of the ciders was 0.74 g/l. Among 51 volatile compounds detected by GC-MS, higher alcohols, esters, and carbonyl compounds were formed in ciders through MLF. The total concentration of aromatic substances doubled compared to the controls. The occurrence of MLF started by strain Z25 enabled the cider containing more volatile compounds and an acceptable adjustment of organic acids. This is the first report on using L. mesenteroides subsp. mesenteroides strain Z25 to start the MLF of apple wine improving the flavour quality of the cider produced.  

scholarly journals Effect of the Use of Purified Grape Pomace as a Fining Agent on the Volatile Composition of Monastrell Wines

Molecules ◽  
2019 ◽  
Vol 24 (13) ◽  
pp. 2423 ◽  
Author(s):  
Gil-Muñoz ◽  
Jiménez-Martínez ◽  
Bautista-Ortín ◽  
Gómez-Plaza
Keyword(s):  
Volatile Compounds ◽  
Red Wine ◽  
Environmental Pollutant ◽  
Grape Pomace ◽  
Wine Aroma ◽  
Volatile Content ◽  
Total Volatile ◽  
Similar Extent ◽  
Fining Agents ◽  
Fining Agent

(1) Background: The lack of viable alternatives for the industrial exploitation of grape pomace is one of the reasons why it is considered a serious environmental pollutant. However, as a byproduct, it could be used as a fining agent, since previous studies have shown that it is able to eliminate undesirable substances in wine. However, the little information available does not describe its effect on wine aroma. (2) Methods: Purified grape pomace extracts were used for fining a red wine and their effect on the volatile compounds of the wine was assessed, comparing the results with those obtained with different commercial fining agents. (3) Results: The results showed how purified grape pomace decreased the total volatile content of a wine to a similar extent as other fining products, such as yeast extracts or gelatin. Among the different families of volatile compounds analyzed, only total esters and terpenes differed from the levels recorded for a control wine, being slightly lower. No statistical differences were found for the rest of the volatile compounds (alcohols, carbonyl, lactones, and acids) compared with the levels measured in control wine. (4) Conclusions: The results suggest that purified grape pomace could be used as a non-allergenic wine fining agent.

Purification and properties of polygalacturonic acid trans-eliminase from Bacillus stearothermophilus

1980 ◽  
Vol 26 (3) ◽  
pp. 377-384 ◽  
Author(s):  
A. Karbassi ◽  
R. H. Vaughn
Keyword(s):  
Bacillus Stearothermophilus ◽  
Ethylenediaminetetraacetic Acid ◽  
Thermophilic Bacteria ◽  
Maximum Activity ◽  
Polygalacturonic Acid ◽  
Pectic Acid ◽  
Heat Stable ◽  
Pectolytic Activity ◽  
Purification And Properties ◽  
Optimal Ph

A strain of thermophilic bacteria, Bacillus stearothermophilus, with pectolytic activity has been isolated. It produced an endo-polygalacturonic acid trans-eliminase (endo-PATE, EC 4.2.2.1) extracellularly when grown at 65 °C on a pectic acid medium. The PATE was purified 62-fold by the rapid affinity chromatographic method on a Sepharose–polygalacturonamide linked matrix. The absorbed PATE was eluted from the column with a continuous gradient of 0–10−3 M ethylenediaminetetraacetic acid (EDTA) in phosphate buffer at pH 7.6.The endo-PATE of this organism was much more heat stable than similar enzymes from the mesophilic Bacillus polymyxa and the thermotolerant Bacillus pumilus. The maximum activity of the enzyme occurred at 70 °C. With pectic acid as the substrate, the endo-PATE had an optimal pH of 9.0, the highest optimal pH compared with those of similar enzymes from other species of the genus.The molecular weight of the endo-PATE, as determined by chromatography on a Sephadex G-100 gel column, was 24 000.

scholarly journals THE ENHANCEMENT OF CHLOROFORM-INDUCED PLASMA PROTEOLYTIC ACTIVITY BY EPSILON AMINOCAPROIC ACID

1962 ◽  
Vol 115 (4) ◽  
pp. 695-706 ◽  
Author(s):  
Virginia H. Donaldson ◽  
Oscar D. Ratnoff
Keyword(s):  
Ionic Strength ◽  
Proteolytic Activity ◽  
Fibrinolytic Activity ◽  
Proteolytic Enzyme ◽  
Aminocaproic Acid ◽  
Heat Stability ◽  
Hydrolytic Activity ◽  
Casein Hydrolysis ◽  
Epsilon Aminocaproic Acid ◽  
Optimal Ph

The proteolytic activity in chloroform-treated plasma euglobulins has been attributed to plasmin. Plasmin can digest both casein and fibrin. Epsilon aminocaproic acid, which inhibits the activation of plasminogen, the precursor of plasmin, by streptokinase, urokinase, and tissue activators enhanced the development of casein hydrolytic activity in a mixture of chloroform and plasma euglobulins. Fibrinolytic activity was also enhanced, but this was evident only if the epsilon aminocaproic acid was removed from the chloroform-treated euglobulins prior to assay. The reasons for the paradoxical enhancement of chloroform-induced casein hydrolysis by euglobulins containing epsilon aminocaproic acid are unclear. However, studies of optimal pH, heat stability, and the effect of ionic strength on the activation of the precursor of this proteolytic enzyme do not differentiate it from plasminogen.

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