Amounts Of Hydrolysis Products Research Articles

Hydrolysis of Oat Starch by Amyloglucosidase and Pullulanase

AbstractThis study describes the enzymatic conversion of oat starch to maltose and glucose under laboratory conditions. First, oat starch is isolated by two different extraction methods (alkali and acid‐alkali). Second, enzymatic starch hydrolysis is carried out for 10% and 12.5% starch solutions obtained by both extraction methods. Third, pullulanase usage together with amyloglucosidase is investigated during saccharification. Finally, effects of the extraction method, starch concentration, and use of pullulanase are evaluated. The use of a 12.5% starch solution obtained by the acid‐alkali method results in higher rates of conversion of starch to glucose and maltose, expressing better substrate for syrup production compared to alkali starch. The use of pullulanase increases the rate of starch conversion to glucose and maltose. The highest conversion of starch to glucose is found to be 49.06% when pullulanase (12 U) is used with amyloglucosidase. The highest dextrose equivalence (DE) value is 97.71, and it is obtained by using pullulanase in 10% ​​acid‐alkali starch. The data obtained in the study show that oat starch can be a suitable source for use in sugar syrup production. The 12.5% starch ​​concentration provides high yield, and the use of pullulanase increases both the amount of hydrolysis products and the DE value.

Effects of Commercial Nitrilase Hydrolysis on Acrylic Fabrics

This study aims to evaluate the hydrolytic activity of a commercial nitrilase and optimize nitrilase treatment conditions to apply eco-friendly finishing on acrylic fabrics. To assess the possibility of hydrolyzing nitrile bonds in acrylic fabric using a commercial nitrilase, the amounts of hydrolysis products, ammonia and carboxylate ions, were measured. The treatment conditions were optimized via the amount of ammonia. The formation of carboxylate ions on the fabric surface was detected by X-ray photoelectron spectroscopy and wettability measurements. After nitrilase treatment, ammonia was detected in the treatment liquid; thus, nitrilase hydrolyzed the nitrile bonds in acrylic woven fabric. The largest amount of ammonia was released into the treatment liquid under the following conditions: pH 8.0, <TEX>$40^{\circ}C$</TEX>, and a treatment time of 5 h. The formation of carboxylate ions on the acrylic woven fabric surface by nitrilase hydrolysis was proven by the increased O1s content measuring of XPS analysis. From comparison of the results of nitrilase and alkaline hydrolysis, the white index and strength of the alkali-hydrolyzed acrylic fabric decreased, whereas those of the nitrilase-hydrolyzed samples were maintained. The nitrilase hydrolysis improved the sensitivity of acrylic fabrics to basic dye similarly to alkaline hydrolysis without the drawbacks of yellowing and decreased strength caused by alkaline hydrolysis.

Study of the urea hydrolysis kinetics in the precipitation conditions of hydroxides and metal salts

The results of studies of the urea hydrolysis kinetics in the temperature conditions corresponding to the precipitation conditions of hydroxides and metal salts were presented. The research was carried out at temperatures of 80-100 °C. The process mechanism was determined - the first-order reaction takes place, the kinetic equation of the urea hydrolysis process was obtained, the dependence of the reaction rate on temperature was defined. The activation energy - 88 kJ, indicating the process flow in the kinetic region was calculated. The rates of accumulation of the hydrolysis products - ammonia and carbon dioxide, which are precipitators of hydroxides and metal salts, in the solution were experimentally studied. It was found that in the hydrolysis process, the amount of ammonia and carbon dioxide in the solution decreases. The temperature at which the there is the highest amount of hydrolysis products in the solution is 90 °C.

Diversity in Production of Xylan-Degrading Enzymes Among Species Belonging to the Trichoderma Section Longibrachiatum

Xylan is an important part of plant biomass and represents a renewable raw material for biorefineries. Contrary to cellulose, the structure of hemicellulose is quite complex. Therefore, the biodegradation of xylan needs the cooperation of many enzymes. For industrial production of xylanase multienzyme complexes (cocktails) and selected monocomponent xylanases, different Trichoderma reesei mutants and recombinants are used. T. reesei QM 6a (wild-type parent of best existing mutants) was selected as a starting material in the 1960s when the modern in-depth analytical methods were not yet in use. Therefore, screening of fungi genetically close to T. reesei in biodegradation of xylan may have a scientific value. Fifteen different strains from Trichoderma section Longibrachiatum have been tested for extracellular xylan-degrading enzyme production on three carbon sources (wheat straw, corn fiber, and eucalyptus wood) in shake flask cultivation. The enzyme activities were evaluated by traditional colorimetric enzyme assays and by HPLC and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Degradation of xylan was studied on four different xylan-rich model substrates. T. reesei CPK 155, Trichoderma parareesei TUB F-2535, and Trichoderma gracile TUB F-2543 isolates were equally good or better in degradation of the wheat arabinoxylan (WAX) and corn fiber alcohol insoluble solids as hydolysis substrates than the well-known T. reesei QM 6a and RUT C30 strains. Though Trichoderma saturnisporum ATCC 18903 gave relatively low volumetric enzyme activities by traditional colorimetric assays, it could release quite large amount of hydrolysis products (mono- and oligosaccharides) from WAX. Therefore, these fungi may be potential candidates for further experiments. Enzyme production on wheat straw and corn fiber carbon sources was more effective than on eucalyptus wood.

Interactions of radionuclides in solution with ions and with trace concentrations of solid phase

Abstract Interactions of radionuclides in extremely low concentrations were determined by measurement of their apparent self-diffusion coefficients. Formation of trace amounts of hydrolysis products, hydroxides of RuIV, MnIV, FeIII, EuIII and of ionic precipitate of AgI were determined from apparent self-diffusion coefficients. Transition of 85Sr2+ by ion exchange or by coprecipitation into trace amounts of FeIII-hydroxide and MnIV-hydrated oxide was revealed by this method. 85Sr2+ sorbed on trace amounts of FeIII-hydroxide and MnIV-hydrated oxides lost its individual chemical properties. This can negatively affect its separation from solution. Formation of unstable embryos of Ag131I trace precipitate in unsaturated solution at concentration of Ag+ 1 · 10−9 mol · l−1 and 131I−1 · 10−8 mol · l−1 was detected by self-diffusion. Formation of trace amounts of Ag131I led to the decrease of sorption of 131I− on hydrated ferric oxide.

Inhibiting properties and adsorption of some thioamides on mild steel in sulphuric acid solutions

The inhibiting properties and adsorption behaviour of thioacetamide (TAA), thiobenzamide (TBA) and thiocinnamamide (TCA) on mild steel in sulphuric acid solution were studied by gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. TBA and TCA were found to be mixed type inhibitors providing good corrosion inhibition. Different mechanisms of adsorption and corrosion inhibition were observed for the tested thioamides. In the cases of TBA and TCA, the adsorption of the compounds is chemical and the values of the activation energy (Ea) and the pre-exponential factor (A) are lower than the corresponding values observed in inhibitor free solution. The adsorption of TAA is physical and the values of Ea and А are higher than the corresponding values in sulphuric acid solution. The adsorption process of TBA and TCA on the mild steel/sulphuric acid solution interface is described by Langmuir’s isotherm. A correlation between the adsorption capability and the inhibiting efficiency of the molecules and their donor–acceptor properties (E HOMO and E LUMO) has been established. It is ascertained that the protection effect of TAA depends on the amount of hydrolysis products.

Effects of grinding and tableting on physicochemical stability of an anticancer drug, TAT-59.

The effects of grinding and tableting on the physicochemical stability of TAT-59, (E)-4-[1-[4-[2-(dimethylamino)ethoxy]phenyl]-2-(4-isopropyl) phenyl]-1-butenyl]phenyl monophosphate, were studied. The crystallinity of TAT-59 ground in a planetary ball mill for 0-120 min or compressed at 0-4500 kg/cm2 was evaluated by X-ray diffraction analysis and differential scanning calorimetry (DSC). The surface of TAT-59 was measured under a scanning electron microscope (SEM). The physicochemical stability of TAT-59, ground or compressed, was determined by measurements of water content, crystallinity and the amount of hydrolysis product, DP-TAT-59, formed. The crystallinity of ground TAT-59 decreased with increasing grinding time, and the amount of DP-TAT-59 increased with decrease in the crystallinity. Similar to ground TAT-59, the crystallinity of TAT-59 tablet gradually decreased with increasing compression pressure, and the amount of DP-TAT-59 tended to increase with decreasing crystallinity. These findings suggested that the decrease of the crystallinity of TAT-59 by mechanical force, such as grinding and tableting, raised the drug's reactivity and affected its stability.

Effects of compression pressure on physical and chemical stability of tablets containing an anticancer drug TAT-59.

(E)-4-[1-[4-[2-(Dimethylamino)ethoxy]phenyl]-2-(4-isopropyl) phenyl]-1-butenyl]phenyl monophosphate (TAT-59) is a new drug for the treatment of breast cancer. Physical and chemical stability of mixtures of TAT-59 and microcrystalline cellulose (1:9) compressed at 0, 300, 600 and 1400 kg/cm2 was evaluated by determination of water content, porosity and the amount of hydrolysis product, DP-TAT-59, formed. The water contents and porosity of these tablets scarcely changed during 57 d at 25-60 degrees C under 50% relative humidity (RH). The degradation rate of TAT-59 increased with increasing compression pressure as well as temperature. The apparent activation energy and frequency factor were determined from an Arrhenius plot of the degradation rate. Activation energy of these tablets was almost the same, while the frequency factor tended to increase with increasing compression pressure. The porosity and pore sizes in TAT-59-containing tablets decreased with increasing compressive force. We speculated from these observations that the increase in compression pressure decreased the distance and increased the contact area between TAT-59 and microcrystalline cellulose. The proximity between TAT-59 and moisture presented at the surface of microcrystalline cellulose by compression was considered to enhance the degradation of TAT-59.

Influence of the reaction medium on enzyme activity in bio-organic synthesis: behaviour of lipase from Candida rugosa in the presence of polar additives.

Lipase from Candida rugosa immobilized on Celite was employed as the biocatalyst in order to examine the effect of the reaction medium upon enzymic activity and selectivity. As the model reaction, transesterification between tributyrin and pentan-2-ol in iso-octane (2,2,4-trimethylpentane) was chosen. A small amount of water (0.05%, v/v) was added to the reaction medium. Enhanced transesterification yields and increased selectivity of the lipase could be obtained by manipulating the microenvironment of the catalyst. Addition of 0.2% NN-dimethylformamide allowed a 93% higher ester yield compared with that obtained when no extra addition was made. Under the same conditions, the ratio of the amount of transesterification product over the amount of hydrolysis product after 48 h, became 52% higher than the ratio determined in the absence of additives. It was concluded that addition of compounds that have low logP3 (P is the partition coefficient in the octanol/water two-phase system) values and high dielectric constant was advantageous in order to favour transesterification over hydrolytic processes.