481. Simple and rapid methods for the estimation of bacterial phosphatases using di-sodium p–nitrophenylphosphate as substrate

1952 ◽  
Vol 19 (3) ◽  
pp. 275-287 ◽  
Author(s):  
J. Tramer
Keyword(s):  
Alkaline Solution ◽  
Bacterial Suspension ◽  
Optimal Conditions ◽  
Yellow Colour ◽  
Rapid Methods ◽  
Measured Amount ◽  
Close Relationship ◽  
Hydrolysis Of

Bacterial phosphatases of growing organisms can be simply demonstrated by incorporating di–sodium–p–nitrophenylphosphate (pNPP) into suitable media. The phosphatase content of a bacterial suspension can be assessed by incubating a measured amount of it with unbuffered or suitably buffered pNPP solutions. The yellow colour (in alkaline solution) of p-nitrophenol liberated from the substrate by phosphatase can be measured accurately and conveniently in a photoelectric absorptiometer, or estimated in a Lovibond comparator using permanent colour standards. The usefulness of the tests for differentiating between members of certain genera is demonstrated by the reactions of Bact. aerogenes and Bact. cloacae, for which a close relationship between phosphatase production and gelatine liquefaction times has been found. The optimal conditions for hydrolysis of pNPP by the phosphatase of a strain of Bact. aerogenes have been established.

Modeling and Optimization of Lipase-Catalyzed Partial Hydrolysis for Diacylglycerol Production in Packed Bed Reactor

2016 ◽  
Vol 12 (7) ◽  
pp. 681-689 ◽  
Author(s):  
Eng-Tong Phuah ◽  
Yee-Ying Lee ◽  
Teck-Kim Tang ◽  
Oi-Ming Lai ◽  
Thomas Shean-Yaw Choong ◽  
...  
Keyword(s):  
Immobilized Enzyme ◽  
Rhizomucor Miehei ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Partial Hydrolysis ◽  
Optimal Conditions ◽  
Lack Of Fit ◽  
Bed Height ◽  
Hydrolysis Of ◽  
Quadratic Models

Abstract Response surface methodology (RSM) was employed to optimize the process variables namely packed bed height (cm) and flow rates (ml/min) on diacylglycerol (DAG) production via partial hydrolysis of palm oil using immobilized Rhizomucor miehei lipase in packed bed reactor (PBR). Quadratic models were successfully developed for both DAG(y) and unhydrolyzed triacylglycerol ((un)TAG) with determination coefficient (R2) of 0.9931 and 0.9986, respectively coupled with insignificant lack of fit (p > 0.05). Optimal conditions for DAG synthesis were evaluated to be 10 cm packed bed height and 3.8 ml/min flow rate. Immobilized enzyme can be reused up to 10 times without significant changes in enzymatic activity. The partial hydrolysis under studied was found to be mass transfer-controlled.

The hydrolysis of maleimide in alkaline solution

1976 ◽  
Vol 54 (9) ◽  
pp. 1400-1404 ◽  
Author(s):  
Remigio Germano Barradas ◽  
Stephen Fletcher ◽  
John Douglas Porter
Keyword(s):  
Alkaline Solution ◽  
Reaction Scheme ◽  
Rate Equations ◽  
Bulk Concentration ◽  
Rate Of Reaction ◽  
Ph Range ◽  
Derived Data ◽  
Hydrolysis Of

The hydrolysis of maleimide has been investigated in the pH range 8.5–14. Polarographic limiting currents were well-defined, so that the bulk concentration of reactant during reduction could be clearly followed as a function of time. Logarithmic analysis of derived data indicated an arrest in the rate of reaction at circa pH 12, and a reaction scheme is proposed to explain this. In this scheme, the neutral maleimide molecule exists in equilibrium with its anion, and both of these species may undergo hydrolysis at the appropriate pH. From derived rate equations, the pKa of maleimide was found to be 10.0, whilst estimates of the rates of hydrolysis were also calculated.

scholarly journals Optimization of lupine hydrolyzate separation

2019 ◽  
Vol 292 ◽  
pp. 01026
Author(s):  
Jiří Pecha ◽  
Jakub Husár ◽  
Miloš Jelínek ◽  
Lubomír Šánek ◽  
Karel Kolomazník
Keyword(s):  
Mathematical Model ◽  
Mass Distribution ◽  
Molar Mass ◽  
Separation Process ◽  
Degree Of Hydrolysis ◽  
Optimal Conditions ◽  
Mixture Separation ◽  
Process Simulations ◽  
Promising Source ◽  
Hydrolysis Of

Lupine hydrolyzate is a promising source of proteins. Hydrolysis of lupine flour was studied under various conditions and their influence on reaction mixture separation by means of filtration was assessed. A mathematical model describing separation process was suggested and verified. This model was used in further calculations and process simulations. It was shown, that the filtration largely depends on the molar mass distribution, respectively the degree of hydrolysis. In addition, an approach enabling optimizing filtration was presented. The time of filtration performed at optimal conditions was almost ten times decreased.

ESTIMATION OF CORTICOSTEROIDS BY THE REDUCTION OF FERRICYANIDE

1959 ◽  
Vol 37 (1) ◽  
pp. 391-398 ◽  
Author(s):  
N. R. Stephenson
Keyword(s):  
Prussian Blue ◽  
Blood Sugar ◽  
Alkaline Medium ◽  
Alkaline Solution ◽  
Reducing Power ◽  
Hydroxyl Group ◽  
Side Chain ◽  
Inhibiting Effect ◽  
Reducing Activity ◽  
Hydrolysis Of

A procedure based on a modification of Folin's micromethod for blood sugar (1, 2) was used to investigate the reducing activity of various corticosteroids. The ferrocyanide produced as a result of the reduction of ferricyanide in alkaline solution was measured photometrically as Prussian blue. With a filter transmitting light at 620 mμ, the relation between the absorbance of the chromogen and the amount of the reducing steroid obeyed Beer's law over the range from 0.005 to 0.050 mg. The oxygen function at C-3 accounted for most of the reducing power of the non-alpha ketolic steroids studied. An oxygen function at C-11 did not affect significantly the reduction of ferricyanide by 17-desoxycorticosteroids. Although the presence of a hydroxyl at C-17 depressed the reducing activity of the alpha-ketol side chain, a fluorine at C-9 and an hydroxyl at C-11 appeared to overcome this inhibiting effect. Evidence was obtained to suggest that a C-16 hydroxyl group was able to increase the reducing action of the alpha-ketolic side chain. Esterification of the C-21 hydroxyl influenced the reduction of ferricyanide only when interference with hydrolysis of the ester in the alkaline medium was experienced.

REACTIONS OF OXODELCOSINE AND INTERRELATION OF DELCOSINE AND DELSOLINE

1960 ◽  
Vol 38 (12) ◽  
pp. 2433-2440 ◽  
Author(s):  
Vinko Skarić ◽  
Léo Marion
Keyword(s):  
Sodium Borohydride ◽  
Membered Ring ◽  
Lead Tetraacetate ◽  
The Other ◽  
Supporting Evidence ◽  
Close Relationship ◽  
Suggested Structure ◽  
Hydrolysis Of

The oxidation of diacetyldelcosine produces a lactam which, after hydrolysis of the acetyl groups, can be oxidized further to a diketo-lactam in which one of the keto groups is in a five- and the other in a six-membered ring. This result leads to an alteration of the previously suggested structure of delcosine. The new structure suggests a close relationship between delcosine and delsoline which is confirmed by the methylation of the former. The reaction is selective and gives rise to a monomethyldelcosine identical in every way with delsoline. Reduction of the diketo-lactam (didehydro-oxodelcosine) with sodium borohydride gives oxodelcosine. Dehydro-oxodelcosine is also described, and its oxidation with lead tetraacetate as well as that of oxodelcosine lead to the formation of keto-products which lend supporting evidence for the structure assigned to delcosine.

Coagulation-filtration of a secondary effluent by means of pre-hydrolyzed coagulants

1996 ◽  
Vol 33 (10-11) ◽  
pp. 193-201 ◽  
Author(s):  
Evangelos Diamadopoulos ◽  
Christos Vlachos
Keyword(s):  
Metal Salts ◽  
Secondary Effluent ◽  
Uv Absorbance ◽  
Optimal Conditions ◽  
Turbidity Removal ◽  
Direct Filtration ◽  
Order Of Magnitude ◽  
Filter Bed ◽  
Hydrolysis Of ◽  
Different Levels

Jar tests were applied to a secondary effluent in order to determine optimal conditions for coagulation. The metal salts Al2(SO4)3, AlCl3 and FeCl3 were used as coagulants, and their efficiency under various degrees of pre-hydrolysis was examined. The variables under examination were the dose of the coagulant, the degree of pre-hydrolysis, B=[OH−]/[Me+3], and the pH at two different levels (pH=5.5 and pH=7.5). The efficiency of the various coagulants was evaluated for the removal of turbidity, phosphorous, COD and UV absorbance at 254 nm. The results showed that as far as turbidity removals are concerned, pre-hydrolysis of the aluminum and ferric chloride coagulants at values of B equal to 0.5 to 1 gave optimal results. However, for phosphorous removal, the higher the degree of pre-hydrolysis, the lower the removal of phosphorous. No remarkable differences were observed for the removal of organic matter measured as COD, while alum gave the best results for the reduction in UV absorbance at 254 nm. Direct filtration of the effluent showed that the coagulant dose required was an order of magnitude lower than that required for coagulation. 35 cm of filter bed were sufficient for effective filtration. All coagulants performed well, increasing the degree of turbidity removal as compared to the absence of coagulants. The lowest headloss rate was observed when alum was used, while the highest headloss rate, almost three times as much, when the aluminum chloride coagulants were used (with and without pre-hydrolysis). Ferric coagulants, with or without pre-hydrolysis, demonstrated intermediate headloss rates.

scholarly journals Comparison of Enzymatic Hydrolysis of Polysaccharides from Eggshells Membranes

2016 ◽  
Vol 15 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Eva Ürgeová ◽  
Katarína Vulganová
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Enzymatic Hydrolysis ◽  
Glucuronic Acid ◽  
Optimal Conditions ◽  
Osteoarthritis Treatment ◽  
Neural Tissues ◽  
Eggshell Membranes ◽  
Hydrolysis Of ◽  
And Cartilage

Abstract AHyaluronic acid (HA) is part of the extracellular matrix of connective, epithelial and neural tissues, as well as the synovial fluid, skin, and cartilage. It is composed of repeating disaccharide units of D-glucuronic acid and N-acetyl glucosamine. Hyaluronic acid is used in abdominal surgery, ophthalmology, dermatology, rhinology; it is usable for the osteoarthritis treatment. The membranes of eggshell are a natural source of hyaluronic acid, collagen, glycosaminoglycan and collagenous proteins. In paper, we tested the possibility of extraction hyaluronic acid from the eggshell membranes by enzymatic hydrolysis. We identified optimal conditions of hydrolysis with trypsin at reaction temperature of 37 °C and pH 8; with pepsin at 40 °C and pH 3, as well as with papain at 60 °C and pH 7.5. The content of hyaluronic acid in samples was determined spectrophotometrically using the carbazole method. The experimental results showed a yield of ~ 4 -4.5 % hyaluronic acid per 1 g of dry eggshell membranes.

scholarly journals OPTIMIZATION FOR BATCH PROTEOLYTIC HYDROLYSIS OF SPENT BREWER’S YEAST BY USING PROTEASES

2018 ◽  
Vol 54 (4A) ◽  
pp. 181
Author(s):  
Nguyen Thi Thanh Ngoc
Keyword(s):  
Ph Value ◽  
Degree Of Hydrolysis ◽  
Optimal Conditions ◽  
Brewer’S Yeast ◽  
Hydrolysis Time ◽  
Brewer's Yeast ◽  
Factors Influencing ◽  
Hydrolysis Temperature ◽  
Hydrolysis Of ◽  
Proteolytic Hydrolysis

The yield of proteolylic hydrolysis for spent brewer’s yeast by protease and aminoacid contents of hydrolysates (the main  factors influencing in taste of hydrolysed product) depends on factors influencing in catalytic activities of enzymes as temperature, pH value, type of used  enzymes and ratio enzyme/substrate. With the purpose to hydrolyse the spent brewer’s yeast for food application, bitterness of hydrolysate takes the firth consideration, and than the yield of hydrolysing process plays economic role. In this paper, it is dealt with determination of optimal conditions to obtain the highest yield of hydrolysis process and the lowest bitterness of hydrolysate (the bitterness is determined by sensory evaluation, expressed equivalently with concentration of quinine). Response surface methodology (RSM) was used to determine optimum condition for batch proteolytic hydrolysis of spent brewer’s yeast. The influencing factors were investigated as temperature (X1): 40 oC–60 oC; pH (X2): 6.0–9.0, ratio E (flavourzyme)/S (X3): 5–10 U/g and hydrolysis time (X4): 6–9 hours. The experimental responses including degree of hydrolysis (Y1) (%) and bitterness of hydrolysate (Y2) (μmol quinine/ml) are performed in second-degree model. The optimal conditions for obtaining high degree of hydrolysis and low bitterness are determined: Ratio of enzyme mixture (alcalase 7.5 U/g and flavourzyme 8.5 U/g), pH 7.5, hydrolysis temperature at 52oC and hydrolysis time 9 hours. Under the optimal conditions, the actual values obtained for the yield of hydrolysis was 40.81  ± 0.044 % and the bitterness equivalently with concentration of quinine was 16.37 ± 0.03 μmol quinine/ml.

Sign in / Sign up

Export Citation Format

Share Document