Source Of Urease Research Articles

Crack healing in cement mortar using enzyme induced calcium carbonate precipitation

The current study highlights a breakthrough approach to crack healing by harnessing the potential of plant-based urease enzymes derived from urease-rich seeds. In this investigation, pulverized watermelon seeds (Citrullus lanatus) served as a valuable source of urease, which facilitated the production of calcium carbonate for crack repair in cement mortar. The healing process involved introducing a specialized suspension, consisting of urea, watermelon seeds’ urease, and calcium hydroxide, into the existing cracks of the specimens. Prior to treatment, the cracked mortar specimens exhibited a substantial 35% reduction in compressive strength as compared to the control specimens. The application of the biocementing suspension led to complete repair of the cracks, resulting in an impressive recovery of approximately 90% of the compressive strength on 7th day, comparable to the control specimens. The UPV results clearly indicated that the crack was healed on the 7th day thus confirming that the proposed biocementing suspension was able to repair the crack completely within 7 days of application. Moreover, the treated i.e experimental specimens demonstrated significant improvements in water tightness, indicating remarkable effectiveness of this crack healing methodology.

Study of enzyme kinetics for urease extracted from Glycine max

Urease is an enzyme that has a key role in nitrogen metabolism in plant germination. Grains are produced more amount of urease than other plants. Glycine max is also called soya bean, a yearly vegetable of the pea family Fabaceae and it’s an eatable seed. Glycine max is mostly used as protein rich legume only, but it has a lot of medical and industrial applications too. Glycine max is used as a source of urease. The goal of this task is to study the kinetic activities of urease enzyme in Glycine max. The first enzyme was extracted from soya beans and partially purified. The enzyme activity was determined in both crude and partially purified using standard procedure. Further, enzyme kinetics (effect of temperature, pH, and substrate concentration) was studied using urease enzyme extracted from soya beans. The purification fold was 1.8 with a yield of 75%. The factors accustomed for its action was pH 8, temperature 50°C, Vmax and Km in Michaelis-Menten plot is 100 units and 8x10-4 moles/litre and LB Plot is 0.25units and 20x10-4 moles/litre.

The effect of the antibiotic tetracycline hydrochloride on the biotransformation of urea when exposed to soil nitrifying strains

Introduction. The consequences of uncontrolled use of antibiotics in agriculture are an urgent problem of environmental hygiene. Tetracycline can enter the soil with the urine of domestic animals, inhibit the vital activity of soil bacterial strains and inhibit the processes of enzymatic hydrolysis of urea (carbamide), disrupting the global nitrogen cycle in nature. The lack of both quantitative and qualitative criteria for assessing this influence determined the relevance of the research. Materials and methods. The studies were carried out using the “Stayer” chromatographic system with cationic and anionic separating columns and exclusive analysis methods developed by the authors. When modelling solutions of heavy metals, an atomic absorption spectrometer MGA - 915MD with ETA was used. The objects of research were model solutions of carbamide with different content of inhibiting substances. As a source of urease and strains of Nitrobacter and Nitrosomonas, sod-podzolic soil from the Educational and Experimental Soil-Ecological Center “Chashnikovo” of Lomonosov Moscow State University was used. Results. An improved, more rapid chromatographic method for the analysis of urea in water is proposed compared to the method described by the authors earlier. The inhibitory effect of the antibiotic tetracycline hydrochloride on the process of biotransformation of nitrite into nitrate caused by Nitrobacter strains has been shown. No significant effect of the antibiotic on the biotransformation of urea into ammonium and ammonium into nitrite under the action of Nitrosomonas strains has been established. Limitations. The studies were carried out on the model of water systems, which included an aqueous phase containing different concentrations of the antibiotic, soil suspension, urea, heavy metal ions at a temperature of t = 30 ○C, pH ~ 6.5. The influence of salt background, pH, and temperature on biotransformation has not been studied, which could, without changing the overall picture, reveal nuances in the kinetics of the main processes. Conclusion. Studies have shown the absence of the effect of the antibiotic tetracycline hydrochloride on the kinetics of the decomposition of urea to ammonium and carbon dioxide due to urease enzymatic activity; there is no effect of the antibiotic on the oxidation of ammonium to nitrites by Nitrosomonas strains. It was found: selective inhibitory effect of an antibiotic during the oxidation of nitrite to nitrate, due to Nitrobacter strains; inhibition of biotransformation processes by chromium ions along the entire chain of transformations from urea to nitrate; and the inhibitory effect of excess oxygen on the totality of biotransformation processes during air bubbling through the aqueous phase.

Longevity of Raw and Lyophilized Crude Urease Extracts

The stability (longevity of activity) of three crude urease extracts was evaluated in a laboratory study as part of an effort to reduce the cost of urease for applications that do not require high purity enzyme. A low-cost, stable source of urease will greatly facilitate engineering applications of urease such as biocementation of soil. Inexpensive crude extracts of urease have been shown to be effective at hydrolyzing urea for carbonate precipitation. However, some studies have suggested that the activity of a crude extract may decrease with time, limiting the potential for its mass production for commercial applications. The stability of crude urease extracts shown to be effective for biocementation was studied. The crude extracts were obtained from jack beans via a simple extraction process, stored at room temperature and at 4 ℃, and periodically tested to evaluate their stability. To facilitate storage and transportation of the extracted enzyme, the longevity of the enzyme following freeze drying (lyophilization) to reduce the crude extract to a powder and subsequent re-hydration into an aqueous solution was evaluated. In an attempt to improve the shelf life of the lyophilized extract, dextran and sucrose were added during lyophilization. The stability of purified commercial urease following rehydration was also investigated. Results of the laboratory tests showed that the lyophilized crude extract maintained its activity during storage more effectively than either the crude extract solution or the rehydrated commercial urease. While incorporating 2% dextran (w/v) prior to lyophilization of the crude extract increased the overall enzymatic activity, it did not enhance the stability of the urease during storage.

Determination of Urease Biochemical Properties of Asparagus Bean (Vigna unguiculata ssp sesquipedalis L.)

Urease is enzyme that plays a role in nitrogen metabolism during plant germination. Plants that produce a lot of urease are grains. This study used asparagus bean as source of urease. The purpose of this research is to learn the effect of germination time on the activity of urease enzyme from asparagus bean and its biochemical properties. The research was started by germination of asparagus bean on day 2, 4, 6, 8, 10 and 12. Asparagus bean sprouts were extracted using acetone and separated by centrifugation to obtain the crude extract of urease. The biochemical properties of the crude extract of urease was further determined including: the effect of temperature, pH, substrate concentration, and metal addition to urease activity. The urease activity is determined by the Nessler method. The germination time of asparagus bean in yielding urease enzyme reached the optimum activity on the 8th day with activity value of 593.7 U/mL. The biochemical properties of urease from asparagus bean have optimum activity at 35 °C, pH 7.0 and substrate concentration 0.125% with activity value of 600 U/mL. Addition of CaCl2, SnCl2 and ZnCl2 metals decrease the activity of urease.

Entrapment of live microbial cells in electropolymerized polyaniline and their use as urea biosensor

The lyophilized biomass of bacterium Brevibacterium ammoniagenes was immobilized in polystyrene sulphonate–polyaniline (PSS–PANI) conducting polymer on a Pt twin wire electrode by potentiostatic electropolymerization. The bacterial cells retained their viability as well as urease activity under entrapped state, as confirmed with bacterial live–dead fluorescent assay and enzymatic assays. The entrapped cells were visualized using scanning electron microscope. The immobilized cells were used as a source of unpurified urease to develop a conductometric urea biosensor. The catalytic action of urease in the sensor released ammonia, thereby causing an increase in the pH of the microenvironment. The pH dependant change in the resistivity of the polymer was used as the basis of sensing mechanism. The sensor response was linear over a range of 0–75mM urea with a sensitivity of 0.125mM−1. The sensor could be reused for 12–15 independent measurements and was quite stable in dry as well as buffered storage condition at 4°C for at least 7 days.

Inhibition factor of ammonification in stored urine with fecal contamination

Inhibition factors of urea hydrolysis caused by fecal contamination as source of urease were investigated. The urea hydrolysis was described by initial ammonification rate (IAR). Three factors for the inhibition (pH, free ammonia nitrogen (FAN) and salinity) were investigated in this study. It was found that the optimum pH value for the urea hydrolysis was obtained at pH 7 (30 degrees C). Similar results were obtained from pH 5 to pH 8 whereas pH 9 provided a little amount of negative effect on the hydrolysis. Significant effect of the FAN as inhibition factor on the urea hydrolysis was obtained in the urea solution: the hydrolysis was observed within 120 mg-N/l of the FAN level in artificial urea solution with fecal contamination. However in storage process of real urine the urea hydrolysis was observed until the FAN level increased up to 2,000 mg-N/l. Salinity obviously provided negative effect on the urea hydrolysis in stored urine with fecal contamination at 30 degrees C. It was assumed that high concentration of the NaCl (150 g/l) was required to achieve 50% reduction of the IAR.

Influence of Urea Treatment and Soybean Meal (Urease) Addition on the Utilization of Wheat Straw by Sheep

The effect of ammoniation with urea and with soybean meal (SBM) as a source of urease on the nutritive value of wheat straw was evaluated in sheep. Twenty-four male Najdi lambs were used in a 3x2 factorial design, in which the animals were allocated to three straw treatments: 0% urea-treated (NT), 6% urea-treated (UT) and 2.2% urea-supplemented (US) straws. Each straw treatment was either supplemented or non-supplemented with 70 g SBM kg - 1 straw during the treatment time with urea, giving a total of six straw treatments. Each of these treatments was individually fed ad libitum to 4 lambs, together with 300 g of barley grain/head/day. Total N content of UT and US straws increased significantly (p 0.05) higher straw DM intake (g d - 1 kg - 1 BW 0 . 7 5 ), compared to those fed NT straw based diet. Apparent DM or OM digestibilities increased significantly (p = 0.014) in lambs fed UT diet, and numerically (p>0.05) in lambs fed US diet as compared to those fed NT diet. Fiber (CF, NDF, ADF, cellulose and hemicellulose) digestibility increased to a similar magnitude, averaging 20.2 (p 0.05) among the treatment diets. This study suggests that US and UT treatments, particularly the latter, improved straw intake, digestibility and N utilization by lambs compared to NT treatment. On the other hand, addition of SBM as a source of urease had a negligible effect on urea hydrolysis.

Direct Coagulation Casting of Alumina Suspensions Using Jack Bean as a Urease Source

This paper reports on the use of Jack bean meal as an alternative source of urease for direct coagulation casting (DCC) processes. Al2O3 suspensions were prepared to compare the effect of Jack bean meal and pure urease on the hydrolysis of urea, the slurry coagulation rate, and the mechanical properties of consolidated bodies. Results indicate that the Jack bean meal is a promising economic alternative for the consolidation of ceramic parts, mainly because of its lower susceptibility to enzyme deactivation when exposed to room temperature and relatively humid environments.

Avaliação de fontes de amônia para o tratamento de fenos de gramíneas tropicais. 1. Constituintes da parede celular, poder tampão e atividade ureática

Avaliaram-se as alterações da fração fibrosa e as características químicas dos fenos de braquiária decumbens (Brachiaria decumbnes Stapf) e jaraguá (Hyparrhenia rufa Ness Stapf) não-tratados, tratados com uréia (U-5,4% da MS), uréia (UL-5,4% da MS) mais labe-labe (Lablab purpureus L. Sweet, cv. Highworth-3,0% da MS) ou amônia anidra (NH3 -3,0% da MS). O tratamento químico com uréia ou NH3 aumentou o pH e a digestibilidade in vitro verdadeira dos fenos. A amonização não alterou os teores de fibra em detergente ácido e celulose, mas diminuiu os de fibra em detergente neutro, hemicelulose e lignina. O uso do labe-labe como fonte adicional de urease não aumentou a eficiência da uréia no tratamento dos volumosos. As avaliações do conteúdo de umidade, do poder tampão e da atividade ureática são técnicas que podem auxiliar na previsão das respostas dos volumosos à amonização com o uso de uréia.

Potentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease

A sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal ( Canavalia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0×10 −4 mol urea l −1, a relative standard deviation of 1.9% ( n=10) and a sampling rate of 20 samples h −1 were observed when 172 Sumner units (SU) of urease and 900 μl of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes.

Growth Performance of Buffalo Male Calves as Affected by Using Cowpeas and Soybean Seeds as A Source of Urease During Urea-Treated Wheat Straw Ensiling Process

Growth Performance of Buffalo Male Calves as Affected by Using Cowpeas and Soybean Seeds as A Source of Urease During Urea-Treated Wheat Straw Ensiling Process

Kinetics of Urea Hydrolysis and Binding of Ammonia to Wheat Straw During Ammoniation by Urea

Chaffed wheat straw treated with urea (5% wt/wt) alone or with rumen liquor, a source of urease (EC 3.5.1.5), was stored in polythene bags at 4, 22, and 37°C up to 60 d. Moisture concentration was adjusted to 40%. Urea remaining in the straw and ammonia concentrations in the bags were measured on 2, 4, 8, 12, 16, 25, 40 and 60 d. Urea hydrolysis increased exponentially with time. Hydrolysis of urea was highest at 22°C followed by 37 and 4°C. Addition of rumen liquor substantially increased rate of urea hydrolysis at all temperatures studied, suggesting that treatment time can be reduced by addition of rumen liquor. Rates of ammonia binding at different temperatures were in the order 22°C> 37°C> 4°C. No hydrolysis of urea was observed up to 7 d of storage at 22 and 37°C when straw was autoclaved and the treatment was carried out under aseptic conditions.

DETOXIFICATION OF GROUNDNUT SEEDS BY UREA AND SUNLIGHT

ABSTRACTA fourteen hour exposure to sunlight destroys about 90 and 77% aflatoxin B1 added to groundnut flakes with and without fat whereas only about 50% of the toxin is destroyed when present as a natural contaminant. Treating the groundnut flakes with 20% urea and 2% soybean flour (a source of urease) at 50% moisture would bring about 70% destruction of aflatoxin B1; In large scale trials, destruction was about 85%. Treatment with urea does not bring down the PER value of the material, which is 1.5 after treatment as against 1.6 in the untreated groundnuts.

Ammonia treatment of straw via the hydrolysis of urea. II. Additions of soya bean (urease), sodium hydroxide and molasses; effects on the digestibility of urea-treated straw

Samples of barley straw were sprayed with solutions of urea (U), urea plus a dry addition of soya bean meal (50 g/kg straw dry matter (DM)) (UB) alone or with sodium hydroxide (15 g/kg straw DM) (UBS), or urea plus molasses (50 g/kg straw DM) (UM). Water was added to lower the DM content of the straw to 700 g kg −1, and the level of urea applied was 70 g/kg straw DM. A further quantity of straw was treated with aqueous ammonia (40 g/kg straw DM). Two-kilogramme lots of each treated straw were sealed in polythene bags and stored for 40 days at 18°C. From the levels of gaseous ammonia in the bags on Day 40, there were indications that the rate of hydrolysis of urea was decreased by treatment UBS, but was increased by molasses addition (UM) compared with straw treated with urea alone (U). The addition of soya bean meal (UB) as a source of urease had no effect. After 48 h incubation in the rumen of steers, samples from Treatments UBS, UB and UM were not significantly different to samples from Treatment U in DM degradability. The DM degradability (%) of a control, untreated straw or samples of straw treated with urea (U) or ammonia (A) was 41.4 < 47.1 < 59.1, respectively ( P < 0.001). Large quantities of straw (200 kg) were treated as for U, UBS, UM and A. The straw was stored in polythene bags for 40 days when the mean ambient temperature was 5.5°C. Diets of treated straw and dried grass (1:1 on a DM basis) were offered to sheep and digestibility was determined. There were no differences in DM digestibility between diets made up with dried grass and straw (U, 0.64; UBS, 0.65; UM, 0.65; A, 0.65). The DM digestibility of dried grass plus untreated straw was 0.56. Apparent DM digestibility of the straw alone in the above diets was 0.49, 0.51, 0.52, 0.51 and 0.34, respectively. Both ammonia and urea treatment significantly ( P < 0.001) increased the digestibility of straw.

The effect of method of urea-ammonia treatment on the subsequent utilization of rice straw by cross bred bull calves

An experiment was carried out with sixty cross bred draught bull calves of 163 kg average liveweight to investigate the effect of six different methods of urea-ammonia treatment on the subsequent utilization of rice straw. Straw treated with 4% urea solution for 3, 9 and 27 days in closed pits and 3 or 9 days in open heaps was compared with untreated straw supplemented with 8·5% ground soyabean. Both 3-day treatments involved 8·5% ground soyabean added at the time of treatment as an external source of urease. Calves fed straw treated with urea and soyabean urease for 3 days in closed pits showed a daily gain of 336 ± 83 g while those on the 27-day closed, 9-day closed, 9-day open and 3-day open treatments showed daily gains of 213 ± 68 g, 307 ± 114 g, 207 ± 65 g and 308 ± 73 g, respectively. Calves on untreated straw supplemented with soyabean powder showed the lowest body weight gain of 141 ± 78 g day −1. It appears that an additional source of urease can reduce the reaction time of urea-treated straw. The 27-day closed system of treatment in cement-lined pits was not only expensive but gave weight gains similar to the 9-day open system of treatment. It is concluded that the economics of treatment and the production potential of the animal concerned should be the final factors in deciding upon the most appropriate method of treatment for farmer's use.

The effect of urease enzyme on treatment time and the nutritive value of straw treated with ammonia as urea

Three experiments were conducted with hammer-milled (10-mm screen) rice and barley straw treated with urea solution, alone or with urease enzyme. In Experiment 1 rice straw was treated with 10, 20, 40, 60 or 80 g urea dissolved in 1 l of water/kg straw, alone or with pure urease, in sealed polythene bags for 1, 2, 6, 14 or 21 days. In Experiment 2 rice straw was treated with 40 or 80 g urea/kg straw and ground soya bean as the source of urease, for 0, 2, 4 or 6 days. Both experiments showed that urea significantly ( P < 0.001) increased organic matter digestibility in vitro and the nitrogen content of the straw. The addition of urease reduced the treatment time to 2–4 days. Ground soya bean appeared to be a satisfactory source of urease for treated straw. In Experiment 3 barley straw was treated with 0, 40 or 80 g urea/kg straw, as in Experiment 1, for 0, 2, 4, 6 or 14 days. Half the treated material was further subjected to a spray treatment with 1 M acetic acid at the time of opening of the bags. Acetic acid treatment significantly ( P < 0.001) depressed organic matter digestibility in vitro of treated straw, but retained 10–15% of the added urea which otherwise would have been lost to the atmosphere as ammonia. It appeared that the urea treatment was inefficient as a means of increasing the nitrogen content of straw. However, the process improved the digestibility of straw and, in the presence of urease, the treatment process could be reduced to 2–4 days.

Jack Bean Meal as Source of Urease in Determination of Urea

Abstract Ground jack bean was added to feed samples as a source of urease in urea determinations. Jack bean meal is much less expensive and is more stable in the presence of soluble salts than is refined urease powder. Percent recoveries in terms of protein equivalent for 3 types of feed ranged from 96.1 to 98.9, using the proposed method. Jack bean meal was equal or superior to refined urease powder in converting urea to ammonia in all samples analyzed.

Urease Activity in the Rumen of Sheep and the Isolation of Ureolytic Bacteria

Urease activity in the sheep rumen varied with the diet of the sheep, but appeared to be largely or entirely present in the small bacterial fraction. Screening of over 1000 strains of rumen bacteria isolated on different media showed that urease activity was apparently confined to species of Staphylococcus, Lactobacillus casei var. casei and Klebsiella aerogenes. Consideration of the numbers in which these occurred and their activities suggested that the bacteria could not be responsible for the total rumen urease activity. By enrichment culture a ureolytic strain of Streptococcus faecium was isolated. This had a higher urease activity than the other bacteria and occurred in higher numbers in the rumen. It could live with other bacteria in the rumen of a gnotobiotic lamb in numbers, and with a urease activity, comparable with those in the normal sheep rumen. The other properties of the bacterium also suggested that it would grow and produce urease in the rumen, but was unlikely to retain its urease activity after isolation. It was concluded that this bacterium was the main source of rumen urease in roughage-fed, and probably other, sheep.