optimum temperature
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2022 ◽  
Vol 2022 ◽  
pp. 1-7
Yandri Yandri ◽  
Ezra Rheinsky Tiarsa ◽  
Tati Suhartati ◽  
Heri Satria ◽  
Bambang Irawan ◽  

The stability of the α-amylase enzyme has been improved from Aspergillus fumigatus using the immobilization method on a bentonite matrix. Therefore, this study aims to obtain the higher stability of α-amylase enzyme from A. fumigatus; hence, it is used repeatedly to reduce industrial costs. The procedures involved enzyme production, isolation, partial purification, immobilization, and characterization. Furthermore, the soluble enzyme was immobilized using 0.1 M phosphate buffer of pH 7.5 on a bentonite matrix, after which it was characterized with the following parameters such as optimum temperature, Michaelis constant (KM), maximum velocity V max , thermal inactivation rate constant (ki), half-life (t1/2), and the change of energy due to denaturation (ΔGi). The results showed that the soluble enzyme has an optimum temperature of 55°C, KM of 3.04 mg mL−1 substrate, V max of 10.90 μmole mL−1 min−1, ki of 0.0171 min−1, t1/2 of 40.53 min, and ΔGi of 104.47 kJ mole−1, while the immobilized enzyme has an optimum temperature of 70°C, KM of 8.31 mg mL−1 substrate, V max of 1.44 μmole mL−1 min−1, ki of 0.0060 min−1, t1/2 of 115.50 min, and ΔGi of 107.37 kJ mole−1. Considering the results, the immobilized enzyme retained 42% of its residual activity after six reuse cycles. Additionally, the stability improvement of the α-amylase enzyme by immobilization on a bentonite matrix, based on the increase in half-life, was three times greater than the soluble enzyme.

2022 ◽  
Vol 9 (12) ◽  
pp. 242-250
Hefti Salis Yufidasari ◽  
Retno Tri Astuti ◽  
Eko Waluyo ◽  
Jekmal Malau

Lipases constitute as top three most important group of enzymes along with  carbohydrases and proteases, and are widely used in various industries. In particular, lipase that perform high activity at low temperatures, or referred as cold adapted lipase (CLPs) considered as attractive catalyst due to its activity at low temperature. This unique feature is the main advantage of cold adapted lipase utilization because it requires a low energy source that is correlated with lower production costs and energy. In addition, reactions occur in cold temperatures may result in better product quality. The purpose of this research was to perform screening and characterization of bacterial cold adapted lipase from seafood cold storage. Among 53 isolates, Kr_16_30, TI_37_14 and Kr_16_28 showed the highest activity with 4.12 U/mL; 3.87 U/mL and 3.21 U/mL, respectively. Isolates Kr_16_30 seemed to be typical cold adapted lipase with optimum temperature at 20°C and pH 7. Isolates Kr_16_28 performed highest lipolytic activity at 30°C while TI_37_14 suspected to be similar to typical mesophilic lipase with optimum temperature at 40°C. Species identification based on 16s rRDA sequencing revealed that isolates Kr_16 30 and Kr_16 28 are belong to genus Pseudomonas and Bacillus, repectively.

2022 ◽  
N. Derbasova

Abstract. The results of photocatalytic activity of tungsten oxide in visible light are analyzed. It was shown that tungsten oxide has photocatalytic activity under the action of visible light in the photodegradation of the dye methylene blue. It was determined that the concentration of 15 mg/L provides the highest rate of photodecomposition of methylene blue. The optimum temperature for the process was determined. The process of methylene blue decomposition is most effective at 25 °С.

М.К. Бахадырханов ◽  
З.Т. Кенжаев ◽  
С.В. Ковешников ◽  
К.С. Аюпов ◽  
Е.Ж. Косбергенов

It has been shown experimentally that nickel clusters on the surface of a silicon sample contain a large amount of oxygen and recombination impurities - Cu, Fe, Cr, which shows good gettering properties of clusters. The optimum temperature of nickel diffusion into silicon is determined - Т=800-850 ° С. Doping with impurity nickel atoms with the formation of clusters makes it possible to increase the lifetime of nonequilibrium charge carriers in the base of a solar cell by up to 2 times, while the formation of a nickel-enriched region in the face layer is more efficient. It is shown that the effect of additional doping with nickel weakly depends on the sequence of the processes of nickel diffusion and the creation of a working p–n-junction.

Mohammed Aman Mujeeb

Abstract: In this investigation a model was made to replicate the working of a shock absorber and the liquid that is used in place of the hydraulic fluid was vegetable oil. Hydraulic fluid is composed of a mineral oil base stock [1]. The working of the model of a shock absorber was tested at different temperatures. It is studied that the relation between the temperature and the time taken by the load attached to the spring to stop oscillating and presented in graph. An optimum temperature, at which the time taken by the mass of 1.50 kilograms suspended in the vegetable oil to stop oscillating and it is the least mass used in the study. In addition to this, the freezing point of the vegetable oil will also be found. It is found in this study that the two variables that is temperature of the vegetable oil and the mass of 1.5 kilograms at rest is linear. Keywords: Temperature Variation, Oil, Oscillation, Mass, Load.

2021 ◽  
Qasim Hussein AHMED ◽  

Abstract The purple scale predator, Rhyzobius lophanthae Blaisdell (Coleoptera: Coccinellidae) is known as coccidophagous ladybird predator, and effective against scales’ insects. The present study aimed to evaluate the optimum temperature for the species to be more efficient. In this study, the life table parameters of R. lophanthae were determined on different temperatures at 4, 16, 18, 20, 22, 24, 26, 28, 30 and 32 °C and 60% RH, by calculations using RmStat-3 software according to Euler-Lotka equation. The results showed that the intrinsic rates of increase (rm) were 0.016, 0.022, 0.030, 0.052, 0.056, 0.068, 0.120, 0.142, 0.132, 0.021 females/females/day, respectively, while the net reproductive rates (R0) were 7.082, 9.514, 11.960, 50.906, 54.150, 49.525, 56.883, 80.944, 31.149, 1.882 females/females/generation, respectively. The mean generation times (T0) were 125.966, 104.602, 84.009, 75.742, 71.511, 57.568, 33.801, 30.866, 25.978, 30.759 days, respectively. Total productivity rates (GRR) were 34.865, 39.210, 48.216, 201.990, 209.469, 166.207, 177.779, 303.751, 105.751, 12.622 egg/female, respectively. The study concluded that 26-30 °C was the optimum temperature range for the efficient role of R. lophanthae under laboratory conditions. From the results, it is still needed to do more studies on the interactions of pests, predators with environmental conditions.

Muhammad Armaghan Siffat ◽  
Muhammad Ishfaq ◽  
Afaq Ahmad ◽  
Khalil Ur Rehman ◽  
Fawad Ahmad

This study is supervised to assess the characteristics of the locally available wheat straw ash (WSA) to consume as a substitute to the cement and support in enhancing the mechanical properties of concrete. Initially, after incineration at optimum temperature of 800°C for 0.5, the ash of wheat straw was made up to the desirable level of fineness by passing through it to the several grinding cycles. Subsequently, the X-ray fluorescence (XRF) along with X-ray diffraction (XRD) testing conducted on ash of wheat straw for the evaluation its pozzolanic potential. Finally, the specimens of concrete were made by consuming 10% and 20% percentages of wheat straw ash as a replacement in concrete to conclude its impact on the compressive strength of high strength concrete. The cylinders of steel of dimensions 10cm diameter x 20cm depth were acquired to evaluate the compressive strength of high strength concrete. The relative outcomes of cylinders made of wheat straw ash substitution presented the slight increase in strength values of the concrete. Ultimately, the C-100 blends and WSA aided cement blends were inspected for the rheology of WSA through FTIR spectroscopy along with Thermogravimetric technique. The conclusions authenticate the WSA potential to replace cement in the manufacturing of the high strength concrete.

2021 ◽  
Vol 937 (2) ◽  
pp. 022099
S Yu Smolentsev ◽  
L M Sufyanova ◽  
A S Makarov ◽  
N Yu Garafutdinova ◽  
O I Shorkina ◽  

Abstract The data on the influence of the temperature regime of the spray drying process on the quality parameters of dry mare’s milk are given. The results of experimental studies on the selection of the optimal drying mode for maximum preservation of the quality indicators of the final product are presented. It was revealed that the optimum temperature during the drying process of mare’s milk is the temperature at the entrance to the dryer t = 180°C, at the exit t = 70-80°C. The study of qualitative indicators with this drying mode showed that the particle size (more than 68%) was 117-140 microns, the solubility index was 0.18 ml of insoluble sediment in 50 ml of reconstituted mare’s milk, the moisture in dry mare’s milk was 3.8% (at t = 180°C), which met all the requirements of the standard. In addition, it was found that the correct heat treatment of mare’s milk before drying also affects the quality indicators of the dry product. The most optimal temperature for milk pasteurization is a temperature of no more than 60°C.

2021 ◽  
Vol 937 (3) ◽  
pp. 032035
Uliyana Alexandrova ◽  
Andrey Kotelnikov ◽  
Svetlana Kotelnikova ◽  
Angelina Firsova ◽  
Anton Kuzov

Abstract The influence of different temperature regimes (28 ° C and 25 ° C) on the early ontogeny of Clarias gariepinus was studied. Heterochronism in the development of the main systems has been provided: the central nervous system and the digestive system are actively developing, the formation of the cardiovascular, respiratory and genitourinary systems occurs more slowly. The duration of embryonic development within the membranes was 18-22 hours. The initial stages of development changed insignificantly with decreasing temperature. The duration of the larval period was 14 days at 28 ° C and 15 days at 25 ° C. The fry period lasted 30 and 32 days, respectively. In terms of the duration of embryogenesis and the timing of the release of free embryos, the indicators did not go beyond the norm. The percentage of ugly embryos (underdevelopment of the operculum, underdevelopment of the tail, head and fins) was small and amounted to 3.2%, in the first and 4% in the second temperature regime. Incubation at temperatures below the optimum temperature of this species makes it possible to obtain viable offspring, adapted to the change in temperature regime.

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Qiutao Liu ◽  
Lingling Jiang ◽  
Lihe Xiao ◽  
Weijun Kong

AbstractThis study aimed to investigate the characteristics, moisture contents, chemical fingerprints changes and aflatoxins accumulation of Atractylodis rhizoma during storage, further to determine the optimum temperature and relative humidity conditions. Based on the suitable temperature (20–40 °C) and relative humidity (80–95%), 13 different temperature and humidity conditions were set up by the central composite design-response surface methodology (CCD-RSM) for Aspergillus flavus. After inoculation with Aspergillus flavus by artificial infection, A. rhizoma samples were stored under normal conditions and 13 different temperature and relative humidity levels. By taking the changes of characteristics, the contents of moisture, chemical fingerprints and aflatoxins as the evaluation indexes for A. rhizoma with or without Aspergillus flavus fungi to optimize the optimal storage conditions. After storage for 10 days, the color of A. rhizoma was deepened, the water content and chemical composition increased, and some unknown components were detected. The susceptible condition for aflatoxins production in A. rhizoma was identified at temperature 22–37 °C and relative humidity over 87.5%. Thus, the suitable storage conditions for A. rhizoma should be controlled at temperature below 20 °C and relative humidity less than 85%. This paper screened out the optimum temperature and humidity for the storage of A. rhizoma. Then, the storage specification for A. rhizoma was proposed, lying technical and data support for the scientific preservation of other food or herbs.

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