scholarly journals Synthesis Polyelectrolyte Complex Membrane Polystyrene Sufonate-Chitosan from Styrofoam Waste as The Adsorbent for Cu(II) and Ni(II) Metal

2021 ◽  
Vol 1 (1) ◽  
pp. 10-25
Author(s):  
Nurillahi Febria Leswana ◽  
Dwi Siswanta ◽  
Adhitasari Suratman
Keyword(s):  
Freundlich Isotherm ◽  
Reaction Rates ◽  
Optimum Composition ◽  
Ph Optimum ◽  
Hydrogen Bond Formation ◽  
Adsorption Mechanisms ◽  
Chitosan Membrane ◽  
Optimum Ph ◽  
Physical Entrapment ◽  
Polystyrene Sulphonate

ABSTRAK Telah dilakukan sintesis membran polistirena sulfonat (PSS)-kitosan dari modifikasi limbah styrofoam, kemudian dipelajari kemampuannya dalam mengadsorpsi logam Ni(II) dan Cu(II). Telah ditentukan pula komposisi optimum PSS-kitosan, uji stabilitas asam basa, dan kemampuan swellingnya. Parameter kajian adsorpsi yang dipelajari dalam penelitian ini meliputi pH optimum, kinetika adsorpsi, isoterm adsorpsi, pengaruh kation lain secara selektifitas, dan penentuan mekanisme adsorpsi. Analisis logam Cu(II) dan Ni(II) sebelum dan sesudah proses adsorpsi dilakukan dengan menggunakan metode Spektrofotometri Serapan Atom (SSA) Hasil penelitian menunjukkan  bahwa polistirena sulfonat (PSS) berhasil diperoleh dari reaksi sulfonasi limbah styrofoam yang ditunjukan dengan spektra FTIR. Komposisi optimum membran PSS:kitosan untuk mengadsorpsi logam Cu(II) dan Ni(II) adalah  perbandingan 60:40 dengan kestabilan, sifat fisik, dan kemampuan adsorpsi yang paling baik. Keadaan pH optimum adsorpsi logam Cu(II) dan Ni(II) berada pada pH 5, waktu optimum berturut-turut 45 menit dan 60 menit, serta konsentrasi optimum berturut-turut 60 ppm dan 40 ppm. Model kinetika dan isoterm adsorpsi logam Cu(II) dan Ni(II) pada membran PSS-kitosan adalah orde kedua semu (McKay dan Ho) dan model isoterm Freundlich. Tetapan laju reaksi logam Cu(II) dan Ni(II) pada pH 5 berturut-turut 0,480 mmol/g-1menit-1 dan 0,423 mmol/g-1menit-1. Adanya logam Ni(II) dalam adsorpsi Cu(II) tidak memberikan pengaruh yang signifikan sampai pada perbandingan Ni(II)/Cu(II)= 2:1, namun sebaliknya dengan kehadiran logam Cu(II) pada adsorpsi logam Ni(II) sudah memberikan pengaruh pada perbandingan Ni(II)/Cu(II)=1:1. Afinitas membran PSS-kitosan terhadap logam adalah Cu(II) > Ni(II). Pada studi desorpsi diketahui jenis interaksi antara adsorbat dan situs aktif adsorben merupakan mekanisme pembentukan kompleks, pemerangkapan dan pembentukan ikatan hidrogen.   ABSTRACT Synthesis of polystyrene sulphonate (PSS) – chitosan membrane of styrofoam waste modification and its ability to adsorb Ni (II) and Cu (II) metals has been studied. The optimum composition of PSS-chitosan, acidity stability test, and swelling ability have been determined. The parameters of the adsorption study studied in this study include optimum pH, adsorption kinetics, adsorption isotherms, selective cationic effects, and determination of adsorption mechanisms. Analysis of Cu (II) and Ni (II) metals before and after the adsorption process was performed using Atomic Absorption Spectrophotometric (AAS) The results showed that polystyrene sulphonate (PSS) was obtained from the sulfonation of styrofoam waste using the FTIR spectra. The optimum composition of rasio PSS: chitosan membrane for adsorbing Cu (II) and Ni (II) is 60:40 with the best stability, physical properties, and adsorption capability. The optimum pH adsorption of Cu (II) and Ni (II) metals was at pH 5, the optimum time was 45 min and 60 min, and the optimum concentrations were 60 ppm and 40 ppm. The kinetic and adsorption models of Cu (II) and Ni (II) metals on PSS-chitosan membranes are second-order (McKay and Ho) and Freundlich isotherm model. The reaction rates of Cu (II) and Ni (II) reactions at pH 5 were 0.480 mmol / g-1menit-1 and 0.423 mmol / g-1menit-1. The presence of Ni (II) metal in Cu (II) adsorption did not give a significant effect to the ratio of Ni (II) / Cu (II) = 2: 1, but with the presence of Cu (II) metal on metal adsorption Ni (II) have an effect on the ratio of Ni (II) / Cu (II) = 1: 1. The affinity of PSS-chitosan membrane to metal is Cu (II)> Ni (II). Sequential desorption studies showed that the adsorption of Cu (II) and Ni (II) metals on the PSS-chitosan membrane were estimated to follow a complex formation, hydrogen bond formation, and physical entrapment mechanisms.  

scholarly journals A shift in the optimum pH of phospholipase D produced by activating long-chain anions

1969 ◽  
Vol 112 (5) ◽  
pp. 795-799 ◽  
Author(s):  
R. H. Quarles ◽  
R. M. C. Dawson
Keyword(s):  
Phosphatidic Acid ◽  
Phospholipase D ◽  
Activity Profile ◽  
Ph Optimum ◽  
Surface Ph ◽  
Electrophoretic Mobilities ◽  
Low Concentrations ◽  
Optimum Ph ◽  
Long Chain

1. The activity of phospholipase D (phosphatidylcholine phosphatidohydrolase, EC 3.1.4.4) towards ultrasonically treated phosphatidylcholine or large phosphatidylcholine particles activated with ether was maximal near pH5, and there was little activity above pH6. 2. When the enzyme was activated by the addition of phosphatidic acid to large phosphatidylcholine particles the pH optimum was shifted to pH6·5 irrespective of the amount of activator added. 3. When the enzyme was activated with low concentrations of dodecyl sulphate the pH optimum was 5·5 with little activity above pH6. With higher concentrations of dodecyl sulphate the pH–activity profile was shifted upwards towards a pH optimum of 6·5–6·6, the magnitude of the shift depending on the extent of the hydrolysis. 4. The shifts in the pH–activity profiles cannot be correlated with changes in the ‘surface pH’ of the substrate particles calculated from the measurement of their ζ-potentials (electrophoretic mobilities).

scholarly journals Thermostable glucose isomerase from psychrotolerant Streptomyces species

1970 ◽  
Vol 1 ◽  
pp. 6-10 ◽  
Author(s):  
Bidur Dhungel ◽  
Manoj Subedi ◽  
Kiran Babu Tiwari ◽  
Upendra Thapa Shrestha ◽  
Subarna Pokhrel ◽  
...  
Keyword(s):  
Specific Activity ◽  
Fold Increase ◽  
Glucose Isomerase ◽  
Enzyme Concentration ◽  
Maximal Velocity ◽  
Ph Optimum ◽  
Streptomyces Spp ◽  
Optimum Ph ◽  
Optimum Reaction ◽  
Sepharose 4B

Glucose isomerase (EC 5.3.1.5) was extracted from Streptomyces spp., isolated from Mt. Everest soil sample, and purified by ammonium sulfate fractionation and Sepharose-4B chromatography. A 7.1 fold increase in specific activity of the purified enzyme over crude was observed. Using glucose as substrate, the Michaelis constant (KM<) and maximal velocity (Vmax) were found to be 0.45M and 0.18U/mg. respectively. The optimum substrate (glucose) concentration, optimum enzyme concentration, optimum pH, optimum temperature, and optimum reaction time were 0.6M, 62.14μg/100μl, 6.9, 70ºC, and 30 minutes, respectively. Optimum concentrations of Mg2+ and Co2+ were 5mM and 0.5mM, respectively. The enzyme was thermostable with half-life 30 minutes at 100ºC.DOI: 10.3126/ijls.v1i0.2300 Int J Life Sci 1 : 6-10

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.

scholarly journals Immobilization of Isolated Lipase From Moldy Copra(Aspergillus Oryzae)

2011 ◽  
Vol 8 (2) ◽  
pp. 896-902
Author(s):  
Seniwati Dali ◽  
A. B. D. Rauf Patong ◽  
M. Noor Jalaluddin ◽  
Pirman ◽  
Baharuddin Hamzah
Keyword(s):  
Thermal Stability ◽  
Aspergillus Oryzae ◽  
Immobilized Lipase ◽  
Optimum Temperature ◽  
Adsorption Method ◽  
Ph Optimum ◽  
Optimum Ph ◽  
Recovery Technique ◽  
Free Lipase

Enzyme immobilization is a recovery technique that has been studied in several years, using support as a media to help enzyme dissolutions to the reaction substrate. Immobilization method used in this study was adsorption method, using specific lipase fromAspergillus oryzae. Lipase was partially purified from the culture supernatant ofAspergillus oryzae. Enzyme was immobilized by adsorbed on silica gel. Studies on free and immobilized lipase systems for determination of optimum pH, optimum temperature, thermal stability and reusability were carried out. The results showed that free lipase had optimum pH 8,2 and optimum temperature 35 °C while the immobilized lipase had optimum 8,2 and optimum temperature 45 °C. The thermal stability of the immobilized lipase, relative to that of the free lipase, was markedly increased. The immobilized lipase can be reused for at least six times.

scholarly journals FOTODEGRADASI ZAT WARNA REMAZOL BRILLIANT BLUE DENGAN BENTONIT TERIMPREGNASI Fe2O3

Jurnal Kimia ◽  
2017 ◽  
Author(s):  
Made Arie Kusuma Dewi ◽  
Iryanti Eka Suprihatin ◽  
James - Sibarani
Keyword(s):  
Brilliant Blue ◽  
Ph Optimum ◽  
Optimum Ph

Telah dilakukan penelitian mengenai fotodegradasi zat warna remazol brilliant blue dengan fotokatalis Fe2O3-bentonit dan sinar UV. Penelitian ini bertujuan untuk mengetahui konsentrasi katalis optimum, pH optimum larutan, waktu penyinaran optimum dengan sinar UV, dan efektivitas fotodegradasi zat warna remazol brilliant blue. Penentuan kondisi optimum fotodegradasi remazol brilliant blue dilakukan dengan variasi konsentrasi komposit Fe2O3-bentonit sebesar 50-300 mg untuk 25 mL larutan (b/v). Variasi pH larutan yang diteliti sebesar 4,0-10,0 dan variasi waktu penyinaran selama 1-6 jam. Efektivitas proses fotodegradasi ditentukan dengan memvariasikan konsentrasi larutan yaitu 50-500 ppm. Hasil penelitian menunjukkan bahwa kondisi optimum proses fotodegradasi remazol brilliant blue memerlukan 8 g/L fotokatalis Fe2O3-bentonit, pH larutan 6, dan waktu penyinaran dengan sinar UV selama 3 jam. Fotokatalis Fe2O3-bentonit pada kondisi optimumnya efektif untuk mendegradasi larutan remazol brilliant blue pada konsentrasi rendah

scholarly journals Removal of cadmium from aqueous solutions using excised leaves of Quetta pine (Pinus halepensis Mill.)

2015 ◽  
Vol 43 (3) ◽  
pp. 277-281 ◽  
Author(s):  
M Rahman ◽  
S Gul ◽  
M Ajmal ◽  
A Iqbal ◽  
Akk Achakzai
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Pinus Halepensis ◽  
Freundlich Isotherm ◽  
Batch Adsorption ◽  
Adsorption Efficiency ◽  
Cadmium Removal ◽  
Optimum Ph ◽  
Maximum Contact ◽  
Adsorbent Dose

Removal of cadmium from aqueous solution was studied by using Quetta pine (Pinus halepensis Mill.) leaves. Batch adsorption experiments were performed as a function of appropriate equilibrium time, pH, concentration of adsorbate and amount of adsorbent. The optimum pH required for maximum adsorption was found to be 7.0 and the maximum contact time for the equilibrium was 30 minutes at adsorbent dose of 10 g. The maximum adsorption efficiency of cadmium removal was 98.50%. The results were better fitted by Langmuir than Freundlich isotherm. The separation factor of equilibrium 0.12 and 0.67 showed that Quetta pine leaves are good adsorbent of cadmium from aqueous solution DOI: http://dx.doi.org/10.3329/bjb.v43i3.21598 Bangladesh J. Bot. 43(3): 277-281, 2014 (December)

Adsorption and Decoloration of Nitroso Dye Based on Eggshell Membrane

2011 ◽  
Vol 183-185 ◽  
pp. 963-966
Author(s):  
Ning Liu ◽  
Tao Liu
Keyword(s):  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Freundlich Isotherm ◽  
Eggshell Membrane ◽  
Eosin B ◽  
Optimum Ph ◽  
Egg Shell Membrane ◽  
Natural Biomaterial ◽  
Egg Shell

Eggshell membrane is a natural biomaterial with macropores lattice and high surface area. The bio-sorption and decolorization of organic dye eosin B was investigated based on eggshell membrane. The effect of adsorption time, pH value and temperature of eggshell membrane on the decolorization of eosin B was studied. Time for adsorption to reach equilibrium is 100 min. Optimum pH value is 2.0 for the adsorption. And the amount of dye removed by egg shell membrane was increasing as temperature ascending. At room temperature and optimum conditions, 95% of eosin B could be removed and maximum adsorption of 40.9 mg/g had been achieved. The adsorption behavior of eggshell membrane towards eosin B fit well with Freundlich isotherm.

scholarly journals Differences in the autocatalytic cleavage of pro-PC2 and pro-PC3 can be attributed to sequences within the propeptide and Asp310 of pro-PC2

1998 ◽  
Vol 334 (3) ◽  
pp. 531-537 ◽  
Author(s):  
Kathleen SCOUGALL ◽  
Neil A. TAYLOR ◽  
Joanne L. JERMANY ◽  
Kevin DOCHERTY ◽  
Kathleen I. J. SHENNAN
Keyword(s):  
Secretory Pathway ◽  
Cell Types ◽  
Structural Features ◽  
Neuroendocrine Cells ◽  
Acidic Ph ◽  
Ph Optimum ◽  
Equivalent Position ◽  
Optimum Ph ◽  
Pro Region

PC2 and PC3 are subtilisin-like proteases involved in the maturation of prohormones and proneuropeptides within neuroendocrine cells. They are synthesized as zymogens that undergo autocatalytic maturation within the secretory pathway. Maturation of pro-PC2 is slow (t½ > 8 h), exhibits a pH optimum of 5.5 and is dependent on calcium (K0.5 2 mM), while pro-PC3 maturation is relatively rapid (t½ 15 min), exhibits a neutral pH optimum and is not calcium dependent. These differences in the rates and optimal conditions for activation of the proteases may contribute to the diversity of products generated by these proteases in different cell types. Although highly similar, there are two major differences between pro-PC2 and pro-PC3: the presence of an aspartate at position 310 in pro-PC2 compared with asparagine at the equivalent position in pro-PC3 (and all other members of the subtilisin family), and the N-terminal propeptides, which exhibit low sequence identity (30%). With a view to establishing the structural features that might be responsible for these differences in the maturation of pro-PC2 and pro-PC3, Asp310 in pro-PC2 was mutated to Asn, and Asn309 in pro-PC3 was mutated to Asp. Chimaeric proteins were also made consisting of the pro-region of PC2 fused to the mature portion of PC3 and the pro-region of PC3 fused to the mature region of PC2. The wild-type and mutant DNA constructs were then transcribed and translated in an in vitro system capable of supporting maturation of pro-PC2 and pro-PC3. The results demonstrated that Asp310 of pro-PC2 is responsible for the acidic pH optimum for maturation. Thus changing Asp310 to Asn shifted the pH optimum for maturation to pH 7.0. However, changing Asn309 of pro-PC3 to Asp had no effect on the optimum pH for maturation of pro-PC3. A chimaeric construct containing the propeptide of pro-PC2 attached to PC3 shifted the pH optimum for maturation from pH 7.0 to 6.0 and slowed down the rate of maturation (t½ > 8 h). When attached to PC2, the pro-region of pro-PC3 had no effect on the optimum pH for maturation (pH 5.5–6.0), but it did accelerate the rate of maturation (t½ 2 h). These results demonstrate that Asp310 and the pro-region of pro-PC2 contribute to the acidic pH optimum and low rate of maturation of this zymogen relative to its closely related homologue PC3.

HYDROLYSIS OF GLYCEROLPHOSPHATIDES BY PLASTID PHOSPHATIDASE C

1956 ◽  
Vol 34 (5) ◽  
pp. 967-980 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Ethyl Ether ◽  
Phosphatidyl Choline ◽  
Phosphatidyl Ethanolamine ◽  
Enzymatic Reaction ◽  
Phosphatidyl Serine ◽  
Ph Optimum ◽  
Soybean Phosphatide ◽  
Optimum Ph ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Studies of the influence of structural variation in the glycerolphosphatide molecule on the hydrolysis of this class of compounds by plastid phosphatidase C showed that the presence of both fatty acid ester groups is necessary for enzymatic reaction; that release of nitrogenous bases occurred, in the presence of ethyl ether, from phosphatidyl cholines, phosphatidyl ethanolamine, and phosphatidyl serine; and that a phosphatidyl choline was hydrolyzed more rapidly than the corresponding phosphatidyl ethanolamine or phosphatidyl serine. The rate of hydrolysis of phosphatidyl choline was influenced greatly by the chain length and degree of unsaturation of the fatty acids. The corresponding phosphatidic acid formed in the hydrolysis of (dipalmitoyl)- or (dipalmitoleyl)-lecithin by carrot phosphatidase C was isolated. Studies on the hydrolysis of crude soybean phosphatide by phosphatidase C showed that both choline and ethanolamine were liberated in the absence of ethyl ether, at an optimum pH of 4.8; in the presence of ether, the rate of liberation of each base was increased, and the pH optimum was between 4.8 and 6. Soybean phosphatide probably contains a substance that stimulates the enzymatic hydrolysis.

HYDROLYSIS OF GLYCEROLPHOSPHATIDES BY PLASTID PHOSPHATIDASE C

1956 ◽  
Vol 34 (1) ◽  
pp. 967-980 ◽  
Author(s):  
Morris Kates
Keyword(s):  
Ethyl Ether ◽  
Phosphatidyl Choline ◽  
Phosphatidyl Ethanolamine ◽  
Enzymatic Reaction ◽  
Phosphatidyl Serine ◽  
Ph Optimum ◽  
Soybean Phosphatide ◽  
Optimum Ph ◽  
Rate Of Hydrolysis ◽  
Hydrolysis Of

Studies of the influence of structural variation in the glycerolphosphatide molecule on the hydrolysis of this class of compounds by plastid phosphatidase C showed that the presence of both fatty acid ester groups is necessary for enzymatic reaction; that release of nitrogenous bases occurred, in the presence of ethyl ether, from phosphatidyl cholines, phosphatidyl ethanolamine, and phosphatidyl serine; and that a phosphatidyl choline was hydrolyzed more rapidly than the corresponding phosphatidyl ethanolamine or phosphatidyl serine. The rate of hydrolysis of phosphatidyl choline was influenced greatly by the chain length and degree of unsaturation of the fatty acids. The corresponding phosphatidic acid formed in the hydrolysis of (dipalmitoyl)- or (dipalmitoleyl)-lecithin by carrot phosphatidase C was isolated. Studies on the hydrolysis of crude soybean phosphatide by phosphatidase C showed that both choline and ethanolamine were liberated in the absence of ethyl ether, at an optimum pH of 4.8; in the presence of ether, the rate of liberation of each base was increased, and the pH optimum was between 4.8 and 6. Soybean phosphatide probably contains a substance that stimulates the enzymatic hydrolysis.

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