Optimum pH and pH Stability of Crude Polyphenol Oxidase (PPO) Extracted from Five Fruit Samples Commonly Consumed in Kano State, Nigeria

1970 ◽  
Vol 4 (1) ◽  
pp. 26-31
Author(s):  
AB Bello ◽  
MS Sule ◽  
AJ Alhassan
Keyword(s):  
Polyphenol Oxidase ◽  
Cucurbita Pepo ◽  
Carica Papaya ◽  
Psidium Guajava ◽  
Ph Stability ◽  
Effect Of Ph ◽  
Solanum Aethiopicum ◽  
Optimum Ph ◽  
Bush Mango ◽  
Ph Range

The effect of pH on the activity and stability of crude polyphenol oxidase (PPO) extracted from garden egg (Solanum aethiopicum), pawpaw (Carica papaya), pumpkin (Cucurbita pepo), guava (Psidium guajava) and bush mango (Irvingia gabonnensis) fruits were studied. Catechol at concentration of 20 mM was used as a substrate while sodium acetate buffer (0.2 M), pH range between 3.0– 5.5 and sodium phosphate buffer(0.2 M) , pH range between 6.0– 8.5 were used to determine the effect of pH on the PPO activity. Optimum pH values were found to be 6.0,6.5,6.0, 4.5 and 4.0/or 8.0 for the enzyme extracted from Solanum aethiopicum, Carica papaya, Cucurbita pepo, Psidium guajava and Irvingia gabonnensis respectively. The enzyme was found to be stable at the pH range of 5.0-7.5 for the enzyme extracted from garden egg, 6.0-8.0 for that from pawpaw, 4.5-7.0 for that from pumpkin, 4.0-6.5 for that from guava and 3.5-5.5 and 7.0-8.0 for that from bush mango respectively. Increase or decrease of pH from the ranges would cause decrease in the activity of the enzyme, and can be a good way of controlling undesirable changes caused by it in foods. Keywords: Optimum pH, pH stability, Polyphenol oxidase, Common fruits.

scholarly journals OPTIMIZING PRE LIMING PH FOR EFFICIENT JUICE CLARIFICATION PROCESS IN SRI LANKAN SUGAR FACTORIES

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
M.G.G Natasha Sewwandi ◽  
Sandya Ariyawansha ◽  
Buddhika Sampath Kumara ◽  
Aloka Maralanda
Keyword(s):  
Quadratic Model ◽  
Sri Lankan ◽  
Effect Of Ph ◽  
Juice Clarification ◽  
Cane Juice ◽  
Optimum Ph ◽  
Initial Ph ◽  
High Turbidity ◽  
Mean Differences ◽  
Ph Range

- This study was conducted treating with Milk of Lime to reach different pH levels (T1- with Initial pH, T2, T3 and T4 with 6.5, 7.5 and 8.5 of pH respectively) to determine the optimum pre-liming pH which could result in best cane juice clarification in Sri Lankan sugar industries. The experiment design used was RCBD with five replicates. ANOVA followed by Duncan’s Multiple Range Test (DNMRT) were used to identify significant mean differences. Regression analyses were carried out to model the variation of turbidity, mud volume and CaO with change of juice pH. Quadratic model (R2 = 99.2 %, p <0.001) best fitted to explain the effect of pH on turbidity of juice. Effect of pH on deposited mud volume and CaO were explained by cubic models with R2 = 99.4 % (p <0.001) and R2 = 93.9 %, (p <0.001) respectively. Among tested treatments, pH 7.5 is selected as the best for turbidity improvement of the clarified juice while pH 8.5 is the second best. However pH 8.5 (370 ml) was able to deposited significantly high mud volume than pH 7.5 (270 ml). Further, the amount of residual Ca2+ ions in the clarified juice at pH 7.5 (2715 ppm) is clearly lower than the amount of Ca2+ ions remaining in the clarified juice at pH 8.5 (2945 ppm). It is expected to obtain high turbidity and higher mud volume with low sugar inversion at optimum pH. Therefore the results suggest optimum pH range lie around pH 7.5 to 8.5. Conducting similar experiment by using mixed juice extracted from sugar factory mills with pH range around 7.0 to 8.4 at 0.2 increments is suggested to validate the optimum pH.

scholarly journals Kinetic Characterization and Effect of Immobilized Thermostable β-Glucosidase in Alginate Gel Beads on Sugarcane Juice

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Keerti ◽  
Anuradha Gupta ◽  
Vinod Kumar ◽  
Ashutosh Dubey ◽  
A. K. Verma
Keyword(s):  
Storage Stability ◽  
Immobilized Enzyme ◽  
Residual Activity ◽  
Sugarcane Juice ◽  
Ph Stability ◽  
Gel Beads ◽  
Optimum Ph ◽  
Enzyme Change ◽  
Ph Range ◽  
And Storage

A thermostable β-glucosidase was effectively immobilized on alginate by the method of gel entrapment. After optimization of immobilized conditions, recovered enzyme activity was 60%. Optimum pH, temperature, kinetic parameters, thermal and pH stability, reusability, and storage stability were investigated. The Km and Vmax for immobilized β-glucosidase were estimated to be 5.0 mM and 0.64 U/ml, respectively. When comparing, free and immobilized enzyme, change was observed in optimum pH and temperature from 5.0 to 6.0 and 60°C to 80°C, respectively. Immobilized enzyme showed an increase in pH stability over the studied pH range (3.0–10.0) and stability at temperature up to 80°C. The storage stability and reusability of the immobilized β-glucosidase were improved significantly, with 12.09% activity retention at 30°C after being stored for 25 d and 17.85% residual activity after being repeatedly used for 4 times. The effect of both free and immobilized β-glucosidase enzyme on physicochemical properties of sugarcane juice was also analyzed.

scholarly journals Kinetics Properties of Polyphenol Oxidase in Hawthorn (Crataegus spp)

2014 ◽  
Vol 25 ◽  
pp. 29-38 ◽  
Author(s):  
Shahriar Saeidian
Keyword(s):  
Enzyme Activity ◽  
Polyphenol Oxidase ◽  
Thermal Inactivation ◽  
Kojic Acid ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Optimum Ph ◽  
Km Value ◽  
Ph Range ◽  
Menten Constant

Polyphenol oxidase (PPO) from hawthorn was extracted and partially purified through (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in Crataegus spp. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the substrates tested, catechol was the best substrate for PPO with a Km value of 2.2 mM. The optimum pH for PPO activity was found to be 7. The enzyme showed high activity over a broad pH range of 4 - 8. The optimal pH and temperature for enzyme activity were found to be 7 and 40-45 °C, respectively. km value for hawthorn PPO is calculated 22 mM for catechol and 6.7 mM for pyrogallol and 9.7 mM for L-dopa. As can be seen, affinity of PPOs for various substrates varies widely. The enzyme showed a broad activity over a broad pH and temperature range. The thermal inactivation studies showed that the enzyme is heat resistant. The enzyme showed the highest activity toward pyrogallol and no activity toward tyrosine. Of the inhibitors tested, the most potent inhibitors were kojic acid, cysteine and glycine , respectively

Optimizing Pre Liming pH for Efficient Juice Clarification Process in Sri Lankan Sugar Factories

2021 ◽  
Author(s):  
Natasha Sewwandi ◽  
Sandya Ariyawansha ◽  
Buddhika Sampath Kumara ◽  
Aloka Maralanda
Keyword(s):  
Quadratic Model ◽  
Sri Lankan ◽  
Effect Of Ph ◽  
Juice Clarification ◽  
Cane Juice ◽  
Optimum Ph ◽  
Initial Ph ◽  
High Turbidity ◽  
Mean Differences ◽  
Ph Range

Abstract This study was conducted treating with Milk of Lime to reach different pH levels (T1- with Initial pH, T2, T3 and T4 with 6.5, 7.5 and 8.5 of pH respectively) to determine the optimum pre-liming pH which could result in best cane juice clarification in Sri Lankan sugar industries. The experiment design used was RCBD with five replicates. ANOVA followed by Duncan’s Multiple Range Test (DNMRT) were used to identify significant mean differences. Regression analyses were carried out to model the variation of turbidity, mud volume and CaO with change of juice pH. Quadratic model (R 2 = 99.2%, p <0.001) best fitted to explain the effect of pH on turbidity of juice. Effect of pH on deposited mud volume and CaO were explained by cubic models with R 2 = 99.4% (p <0.001) and R 2 = 93.9%, (p <0.001) respectively.Among tested treatments, pH 7.5 is selected as the best for turbidity improvement of the clarified juice while pH 8.5 is the second best. However pH 8.5 (370 ml) was able to deposited significantly high mud volume than pH 7.5 (270 ml). Further, the amount of residual Ca2+ ions in the clarified juice at pH 7.5 (2715 ppm) is clearly lower than the amount of Ca2+ ions remaining in the clarified juice at pH 8.5 (2945 ppm). It is expected to obtain high turbidity and higher mud volume with low sugar inversion at optimum pH. Therefore the results suggest optimum pH range lie around pH 7.5 to 8.5. Conducting similar experiment by using mixed juice extracted from sugar factory mills with pH range around 7.0 to 8.4 at 0.2 increments is suggested to validate the optimum pH.

scholarly journals DENITRIFIKASI LIMBAH NITRAT PADA BERBAGAI TINGKAT KEASAMAN DENGAN MEMANFAATKAN MIKROBA AUTOTROPH

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Rudi Nugroho
Keyword(s):  
Activated Sludge ◽  
Electron Donor ◽  
Elemental Sulfur ◽  
Denitrification Rate ◽  
Effect Of Ph ◽  
Biological Denitrification ◽  
Autotrophic Bacteria ◽  
Optimum Ph ◽  
Shape Equation ◽  
Ph Range

A biological denitrification using autotrophic bacteria in batch suspension runs was investigated to clarify the effect of pH on denitrification rate. Elemental sulfur was employed as an electron donor. The culture of autotrophic bacteria was obtained from activated sludge by acclimatization. The effect of pH on denitrification rate could be expressed by bell-shape equation with optimum pH of 7,07. However at a pH range of 5,5 to 8,0, the denitrification rate significantly fastl. Therefore, the application of the denitrification of wastewater using autotrophic bacteria is suggested running well although without controlling pH.  Kata kunci : Denitrification, nitrate, autotrophic bacteria, elemental sulfur, pH.

scholarly journals Granulicoccus phenolivorans gen. nov., sp. nov., a Gram-positive, phenol-degrading coccus isolated from phenol-degrading aerobic granules

2007 ◽  
Vol 57 (4) ◽  
pp. 730-737 ◽  
Author(s):  
Abdul Majid Maszenan ◽  
He Long Jiang ◽  
Joo-Hwa Tay ◽  
Peter Schumann ◽  
Reiner M. Kroppenstedt ◽  
...  
Keyword(s):  
Batch Reactor ◽  
Rrna Gene ◽  
Aerobic Granules ◽  
New Genus And Species ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Optimum Ph ◽  
Phenolic Wastewater ◽  
Ph Range ◽  
Capsular Material

A Gram-positive bacterium, designated strain PG-02T, was isolated by serial dilution from aerobic granules obtained from a laboratory-scale sequencing batch reactor for bioremediation of phenolic wastewater. Strain PG-02T grew axenically as cocci and is an oxidase-negative and catalase-positive, non-motile facultative anaerobe. It does not reduce nitrate and grows between 15 and 37 °C, with an optimum temperature of 30 °C. The pH range for growth is between 5.0 and 8.5, with an optimum pH of 7.0. Strain PG-02T contains type A3γ peptidoglycan (ll-A2pm←Gly with alanine at position 1 of the peptide subunit). The G+C content of the DNA is 69 mol%. Menaquinone MK-9(H4) was the major isoprenoid quinone. The polar lipids included diphosphatidylglycerol and phosphatidylglycerol, while 13-methyltetradecanoic acid (i-C15 : 0) and 1,1-dimethoxy-iso-pentadecane (i-C15 : 0 DMA) were the major components in whole-cell methanolysates. PG-02T stained positively for intracellular polyphosphate granules but not poly-β-hydroxyalkanoates. It produces capsular material and possesses an autoaggregation capability. Phenotypic and 16S rRNA gene sequence analyses showed that PG-02T differed from its closest phylogenetic relatives, namely members of the suborder Propionibacterineae, which includes the genera Tessaracoccus, Microlunatus, Luteococcus, Micropruina, Propionibacterium, Propioniferax, Nocardioides, Friedmanniella and Aeromicrobium, and that it should be placed in a new genus and species as Granulicoccus phenolivorans gen. nov., sp. nov. The type strain of Granulicoccus phenolivorans is PG-02T (=ATCC BAA-1292T=DSM 17626T).

scholarly journals Evidence that the active centre of chymopapain A is different from the active centres of some other cysteine proteinases and that the Brønsted coefficient (βnuc.) for the reactions of thiolate anions with 2,2′-dipyridyl disulphide may be decreased by reagent protonation

1980 ◽  
Vol 189 (1) ◽  
pp. 189-192 ◽  
Author(s):  
K Brocklehurst ◽  
B S Baines ◽  
M S Mushiri
Keyword(s):  
Carica Papaya ◽  
Cysteine Proteinases ◽  
Active Centre ◽  
Pka Values ◽  
Nitrobenzoic Acid ◽  
Specific Reactivity ◽  
Ph Range ◽  
Thiolate Anions ◽  
Active Centres

The active centres of chymopapains A and B (jointly designated EC 3.4.22.6) and papaya (Carica papaya L.) peptidase A were investigated by using 2,2′-dipyridyl disulphide and 5,5′-dithiobis-(2-nitrobenzoic acid) as thiol-specific reactivity probes. Whereas the first active-centre pKa values for chymopapain B and papaya peptidase A are less than 5, is as the case for papain (EC 3.4.22.2) and ficin (EC 3.4.22.3), that for chymopapain A is about 6.8. The reason why the reactions of thiols of pKa approx. 6.5 with 2.2′-dipyridyl disulphide are essentially pH-independent in the pH range around the thiol pKa is delineated. The value of the Brønsted coefficient (beta nuc.) for the reactions of thiolate ions with the 2,2′-dipyridyl disulphide monocation appears to be smaller than its value for the corresponding reactions with the neutral disulphide.

scholarly journals AmyA, an α-Amylase with β-Cyclodextrin-Forming Activity, and AmyB from the Thermoalkaliphilic Organism Anaerobranca gottschalkii: Two α-Amylases Adapted to Their Different Cellular Localizations†

2005 ◽  
Vol 71 (7) ◽  
pp. 3709-3715 ◽  
Author(s):  
Meike Ballschmiter ◽  
Martin Armbrecht ◽  
Krasimira Ivanova ◽  
Garabed Antranikian ◽  
Wolfgang Liebl
Keyword(s):  
Amino Acid ◽  
Half Life ◽  
Extracellular Enzyme ◽  
Amino Acid Sequences ◽  
Cyclodextrin Glycosyltransferase ◽  
High Similarity ◽  
Ph Optimum ◽  
Transglycosylation Activity ◽  
Optimum Ph ◽  
Ph Range

ABSTRACT Two α-amylase genes from the thermophilic alkaliphile Anaerobranca gottschalkii were cloned, and the corresponding enzymes, AmyA and AmyB, were investigated after purification of the recombinant proteins. Based on their amino acid sequences, AmyA is proposed to be a lipoprotein with extracellular localization and thus is exposed to the alkaline milieu, while AmyB apparently represents a cytoplasmic enzyme. The amino acid sequences of both enzymes bear high similarity to those of GHF13 proteins. The different cellular localizations of AmyA and AmyB are reflected in their physicochemical properties. The alkaline pH optimum (pH 8), as well as the broad pH range, of AmyA activity (more than 50% activity between pH 6 and pH 9.5) mirrors the conditions that are encountered by an extracellular enzyme exposed to the medium of A. gottschalkii, which grows between pH 6 and pH 10.5. AmyB, on the other hand, has a narrow pH range with a slightly acidic pH optimum at 6 to 6.5, which is presumably close to the pH in the cytoplasm. Also, the intracellular AmyB is less tolerant of high temperatures than the extracellular AmyA. While AmyA has a half-life of 48 h at 70°C, AmyB has a half-life of only about 10 min at that temperature, perhaps due to the lack of stabilizing constituents of the cytoplasm. AmyA and AmyB were very similar with respect to their substrate specificity profiles, clearly preferring amylose over amylopectin, pullulan, and glycogen. Both enzymes also hydrolyzed α-, β-, and γ-cyclodextrin. Very interestingly, AmyA, but not AmyB, displayed high transglycosylation activity on maltooligosaccharides and also had significant β-cyclodextrin glycosyltransferase (CGTase) activity. CGTase activity has not been reported for typical α-amylases before. The mechanism of cyclodextrin formation by AmyA is unknown.

Effect of temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37

2021 ◽  
Vol 66 (1) ◽  
pp. 72-79
Author(s):  
Thuoc Doan Van ◽  
Hung Nguyen Phuc
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Animal Feed ◽  
Culture Conditions ◽  
Effect Of Temperature ◽  
Physical Parameters ◽  
Original Activity ◽  
Optimum Ph ◽  
Production Activity ◽  
Ph Range

The effect of physical parameters such as temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37 was investigated. The results indicated that the optimum culture conditions for enzyme activity were pH 7.0 and 35 oC. The optimum pH and temperature for enzyme activity were 6.0 and 70 oC. The crude enzyme was found to be stable in the pH range of 5.0 to 7.0. The enzyme was stable for 1 h at a temperature from 30 to 80 oC; nearly 100% of enzyme activity remained at temperatures of 30 - 40 oC, and about 34% of original activity remained at a temperature of 80 oC. These features demonstrated that α-amylase from B. subtilis V37 can be applied in many areas such as the food, fermentation, and animal feed industries.

SIGNIFICANT EFFECT OF PH ON PHOTOCATALYTIC DEGRADATION OF ORGANIC POLLUTANTS USING SEMICONDUCTOR CATALYSTS

2016 ◽  
Vol 78 (8-3) ◽  
Author(s):  
Nur Farhana Jaafar ◽  
Aishah Abdul Jalil ◽  
Sugeng Triwahyono ◽  
Adnan Ripin ◽  
Mohamad Wijayanuddin Ali
Keyword(s):  
Carbon Dioxide ◽  
Methyl Orange ◽  
Physicochemical Properties ◽  
Photocatalytic Degradation ◽  
Organic Pollutants ◽  
Ph Value ◽  
Effect Of Ph ◽  
Electrolysis Method ◽  
Ph Range ◽  
Positively Charged

Photocatalytic is one of the inexpensive and non-toxic techniques for degradation of organic pollutants into harmless substances such as water and carbon dioxide. In this study, simple electrolysis method was used in preparation of Ag/TiO2 and α-Fe2O3/HY catalysts. The physicochemical properties of the catalysts were studied using XRD, FTIR, FESEM-EDX and surface area analysis. The pH of solution plays an important role in the photocatalytic degradation of organic pollutants which influences the surface-charge properties of the catalysts. Ag/TiO2 and α-Fe2O3/HY were used as catalyst on degradation of 2-chlorophenol (2-CP) and methyl orange (MO), respectively. The effect of pH on degradation of 2-CP and MO were investigated over a pH range from 2 to 9. Higher degradation of 2-CP and MO were obtained at pH 5 (74%) and pH 2 (80%), respectively. This finding might be explained by the amphoteric performance of the catalyst using point zero charge (pHZPC). The pHZPC for Ag/TiO2 and α-Fe2O3/HY was found to be at pH 6.3 and pH 7.2, respectively. Hence, the activities of the catalysts may have been affected by the existence of a strong electrostatic field between the positively charged catalysts surface and negatively charged 2-CP and MO caused a pH value lower than their pHZPC give greater degradation.

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