scholarly journals Analisis Temperatur terhadap Konversi Tepung Jagung ke Molases pada Tahap sakarifikasi

SAINTIFIK ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 8-14
Author(s):  
Sutrisnawati Mehora ◽  
Surya Ningsih
Keyword(s):  
Temperature Optimum

 Temperature sangat mempengaruhi kosentrasi molases dalam menghidrolisis tepung jagung. Kenaikan temperature menyebabkan energy kinetic molekul meningkat. Peningkatan energi yang cukup bagi molekul reaktan akan meningkatkan laju reaksi sehingga semakin tinggi temperature konversi yang diperoleh akan semakin tinggipada temperature yang yang tidak melebihi temperature optimum enzim bekerja. Dalam menghidrolisis tepung jagung ke molases dilakukan tiga tahap yakni, gelatinase, likuifikasi, dan sakarifikasi. Metode penelitian yang digunakan yaitu metode eksperimen yang dilakukan di laboratorium. Hasil penelitian ini diperoleh nilai kadar molases, massa molases, dan nilai efisiensi. Pada temperatur (40-45) oC kadar molases yang dihasilkan yakni 8,8 %, massa molases 19,33 gr, efisiensi 64%. Pada temperatur (45-50) oC kadar molases yang dihasilkan yakni 11,6 %, massa molases 25,69 gr, dan efisiensi 86%. Pada temperatur (50-55) oC kadar molases yang dihasilkan meningkat menjadi 13 %, massa molases 26,27 gr, dan efisiensi 88%. Pada temperatur (55-60) oC kadar molases lebih meningkat menjadi 14,6 %, massa molases 28,86 gr dan efisiensi 90%.. Ini artinya semakin tinggi temperatur maka kadar molases juga akan semakin bertambah. Pada temperatur rentang (40-45) oC hanya sebagian kecil molekul yang memiliki energi aktivasi yang cukup untuk bertumbukan menghasilkan reaksi, sehingga tepung jagung yang berhasil terhidrolisis lebih sedikit, sebaliknya pada temperatur (55-60) oC energi kinetik molekul naik sehingga menyebabkan peningkatan laju reaksi. Pada temperatur tersebut adalah temperatur optimum enzim gluko amilase bekerja. Hal ini bersesuaian dengan distribusi Maxwell-Boltzmann yang menyatakan bahwa reaksi akan semakin cepat dengan adanya pertambahan temperatur.

Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

Biosynthesis of the Diguanosine Nucleotides. I. Purification and Properties of an Enzyme from Yolk Platelets of Brine Shrimp Embryos

1974 ◽  
Vol 52 (3) ◽  
pp. 231-240 ◽  
Author(s):  
A. H. Warner ◽  
P. C. Beers ◽  
F. L. Huang
Keyword(s):  
Molecular Weight ◽  
Brine Shrimp ◽  
Artemia Salina ◽  
Temperature Optimum ◽  
Small Molecular Weight ◽  
Ph Optimum ◽  
Optimal Activity ◽  
Purification And Properties

An enzyme that catalyzes the synthesis of P1P4-diguanosine 5′-tetraphosphate (Gp4G) has been isolated and purified from yolk platelets of encysted embryos of the brine shrimp, Artemia salina. The enzyme GTP:GTP guanylyltransferase (Gp4G synthetase) utilizes GTP as substrate, has a pH optimum of 5.9–6.0, a temperature optimum of 40–42 °C, and requires Mg2+ and dithiothreitol for optimal activity. The synthesis of Gp4G is inhibited markedly by pyrophosphate, whereas orthophosphate has no effect on the reaction. In the presence of GDP the enzyme also catalyzes the synthesis of P1,P3-diguanosine 5′-triphosphate (Gp3G), but the rate of synthesis is low compared with Gp4G synthesis and dependent upon other small molecular weight components of yolk platelets.

Temperature-induced alanine oxidation in a psychrotrophic Pseudomonas

1975 ◽  
Vol 21 (12) ◽  
pp. 2028-2033
Author(s):  
Prince K. Zachariah ◽  
John Liston
Keyword(s):  
Heat Treatment ◽  
Enzyme Synthesis ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sephadex Column ◽  
Oxidase System ◽  
Psychrotrophic Bacteria ◽  
Induction Of Enzymes ◽  
Elution Fraction

A psychrotrophic pseudomonad isolated from iced fish oxidized alanine at temperatures close to 0 °C and grew over the range 0 °C–35 °C. The rate of oxidation of alanine, measured manometrically, by cells grown at 2 °C was lower than that of cells grown at 22 °C. However, the consumption of oxygen after heat treatment at 35 °C for 35 min was reduced considerably by 2 °C grown cells. Alanine oxidase activity was tested in an extract from cells grown at 2 °C and 22 °C with alanine as the sole carbon, nitrogen, and energy source. Cells grown at 2 °C produced an alanine oxidase with a temperature optimum of 35 °C and pH optimum of 8, which lost about 80% activity by heat treatment at 40 °C for 30 min. There was no change in activity after dialysis at pH 7, 8, or 9. Extracts from cells grown at 22 °C contained an alanine oxidase system with an optimum temperature of 45 °C, a pH optimum above 8, and only about 30% reduction of activity after heat treatment. This enzyme activity was concentrated in the 0.5 M elution fraction from a Sephadex column, and dialysis reduced the activity at pH 7 and 8. Mesophilic enzyme synthesis apparently started around a growth temperature of 10 °C.The crude alanine oxidase systems of Pseudomonas aeruginosa derived from cells grown at 13 °C and 37 °C had a common optimum temperature of 45 °C. These data suggest that one mechanism of psychrophilic growth by psychrotrophic bacteria may be the induction of enzymes with low optimum temperatures in response to low temperature conditions.

Cellulase production by Acetivibrio cellulolyticus

1980 ◽  
Vol 26 (7) ◽  
pp. 760-765 ◽  
Author(s):  
J. N. Saddler ◽  
A. W. Khan
Keyword(s):  
Sewage Sludge ◽  
Cellulose Degradation ◽  
Cellulase Production ◽  
Cellulolytic Enzymes ◽  
Exponential Growth Phase ◽  
Cellulose Powder ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Culture Supernate ◽  
Cellulose Concentration

Acetivibrio cellulolyticus, an isolate from an established sewage sludge culture, degraded cellulose powder, Avicel cellulose, and cellobiose. The organism showed maximum cellulose degradation in a medium containing 10 g/L of cellulose and it could also degrade cellulose in media containing up to 75 g/L of cellulose. During the exponential growth phase, large quantities of cellulolytic enzymes were found extracellularly whereas cellobiase activity was cell associated. The crude culture supernate contained endo- and exo-glucanase activities with a pH optimum at 5.0 and a temperature optimum at 50 °C. Maximum cellulase activities were detected in 2- to 3-day-old cultures grown on 1 g/L of cellulose. Cellulose concentration above 10 g/L caused the adsorption of these enzymes to the substrate and consequently lowered their detection in the supernate. The activities at 50 °C for endoglucanase, exoglucanase, and filter paper degrading ability, expressed as micrograms of glucose equivalents released per minute per milligram of protein culture supernate, were 510, 135, and 40 respectively.

Effects of Clone and Irrigation on the Stomatal Conductance and Photosynthetic Rate of Tea (Camellia sinensis)

1994 ◽  
Vol 30 (1) ◽  
pp. 1-16 ◽  
Author(s):  
B. Gail Smith ◽  
Paul J. Burgess ◽  
M. K. V. Carr
Keyword(s):  
Stomatal Conductance ◽  
Camellia Sinensis ◽  
Photosynthetic Rate ◽  
Leaf Temperature ◽  
Temperature Optimum ◽  
Photosynthetic Rates ◽  
Clone Selection ◽  
Treatment Interaction ◽  
Dry Seasons ◽  
The Relationship

SummaryStomatal conductances (g) and photosynthetic rates (A) were monitored in six tea clones planted in a clone X irrigation experiment in the Southern Highlands of Tanzania. Measurements were made during the warm dry seasons of 1989 and 1990. There was no genotype X treatment interaction in the response in A or g of the various clones to irrigation. Irrigation increased A more than it increased g. Irrigation also increased the temperature optimum for photosynthesis and decreased photo-inhibition at high illuminance. Clones differed in g and A, and in the relationship between leaf temperature and A. The implications of these findings for clone selection are discussed.

Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione

1971 ◽  
Vol 26 (7) ◽  
pp. 710-719 ◽  
Author(s):  
Kunhard Pollow ◽  
Barbara Pollow
Keyword(s):  
Hydrogen Transfer ◽  
Microsomal Fraction ◽  
Close Relation ◽  
Inhibitory Effect ◽  
Magnesium Ions ◽  
Michaelis Constant ◽  
Temperature Optimum ◽  
Optimum Ph ◽  
Kinetics Of ◽  
Estradiol 17Β

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.

STUDIES ON SOLUBILIZED ADENYLATE KINASE FROM MITOCHONDRIA

1966 ◽  
Vol 44 (11) ◽  
pp. 1469-1475 ◽  
Author(s):  
Marjorie A. Brewster ◽  
Ezzat S. Younathan
Keyword(s):  
Activation Energy ◽  
Rat Liver ◽  
Adenylate Kinase ◽  
Divalent Cations ◽  
Metabolic Function ◽  
Kcal Mole ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sensitive Method

Adenylate kinase from mitochondria of rat liver was made soluble by sonication. The enzyme had a pH optimum of 8.0, temperature optimum of 30°, and activation energy of 12.2 kcal/mole. It was activated by several divalent cations in the following order of efficiency: Mg++ > Co++ > Mn++ > Ca++, with an optimal Mg++: ADP ratio of 1. The apparent Km value (ADP as substrate) was found to be 1.3 mM at pH 7.4 and 30°. The activity was sensitive to phloretin and mildly activated by aurovertin. Oligomycin, 2,4-dinitrophenol, p-chloromercuribenzoate, alloxan, and phlorizin had no effect on the activity. The metabolic function and a comparison of the properties of this solubilized mitochondrial adenylate kinase with those of similar preparations from other sources are discussed in the light of these findings. During this study, a sensitive method adaptable for a large number of assays of adenylate kinase was developed, and is described in detail.

Isolation and Characterization of a Chlorogenic Acid Esterase from Aspergillus niger

1980 ◽  
Vol 35 (3-4) ◽  
pp. 209-212 ◽  
Author(s):  
B. Schöbel ◽  
W. Pollmann
Keyword(s):  
Enzyme Activity ◽  
Chlorogenic Acid ◽  
Divalent Cations ◽  
Hydrolysis Product ◽  
The Other ◽  
Temperature Optimum ◽  
Pig Liver ◽  
Isolation And Characterization

Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split chloro­genic acid. The isoelectric focusing reveals several isoenzymes of chlorogenase within a pI-range of 4.0-4.5.

Polyphenol Oxidase Enzymes in the Sap and Skin of Mango Fruit

1993 ◽  
Vol 20 (1) ◽  
pp. 99 ◽  
Author(s):  
SP Robinson ◽  
BR Loveys ◽  
EK Chacko
Keyword(s):  
Heat Treatment ◽  
Polyphenol Oxidase ◽  
Catechol Oxidase ◽  
Hexadecyltrimethylammonium Bromide ◽  
Temperature Optimum ◽  
Mango Fruit ◽  
Salicylhydroxamic Acid

Severe sapburn occurs in mango fruit of the cultivar Kensington when sap contacts the fruit, resulting in browning and then blackening of the skin. Both the sap and skin of mango fruit contained considerable polyphenol oxidase (PPO) activity. The sap enzyme was not activated by SDS, was inhibited by hexadecyltrimethylammonium bromide, and was active with both para- and ortho-diphenol substrates. The skin enzyme was activated by SDS, was inhibited by salicylhydroxamic acid and polyvinylpyrrolidone, and was active only with ortho-diphenol substrates. These properties suggest that the sap PPO is a laccase-type enzyme (EC 1.10.3.2) whereas the skin contains the more common catechol oxidase-type PPO (EC 1.10.3.1). The skin enzyme had a temperature optimum at 30�C but the sap enzyme had maximum PPO activity at 75�C. Both enzymes were relatively thermostable, requiring more than 15 min at 80�C for 50% loss of activity. It is concluded that browning of mango skin induced by the sap is predominantly catalysed by PPO in the skin and that this is unlikely to be prevented by heat treatment of the fruit.

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