Organic amendments alleviate early defoliation and increase fruit yield by altering assembly patterns and of microbial communities and enzymatic activities in sandy pear (Pyrus pyrifolia)

Severe early defoliation has become an important factor restricting the development of the pear industry in southern China. However, the assembly patterns of microbial communities and their functional activities in response to the application of bioorganic fertilizer (BIO) or humic acid (HA) in southern China’s pear orchards remain poorly understood, particularly the impact on the early defoliation of the trees. We conducted a 3-year field experiment (2017–2019) in an 18-year-old ‘Cuiguan’ pear orchard. Four fertilization schemes were tested: local custom fertilization as control (CK), CK plus HA (CK-HA), BIO, and BIO plus HA (BIO-HA). Results showed that BIO and BIO-HA application decreased the early defoliation rate by 50–60%, and increased pear yield by 40% compared with the CK and CK-HA treatments. The BIO and BIO-HA application significantly improved soil pH, available nutrient content, total enzyme activity and ecosystem multifunctionality, and also changed the structure of soil bacterial and fungal communities. The genus Acidothermus was positively correlated with the early defoliation rate, while the genus Rhodanobacter was negatively correlated. Additionally, random forest models revealed that the early defoliation rate could be best explained by soil pH, ammonium content, available phosphorus, and total enzyme activity. In conclusion, application of BIO or BIO mixed with HA could have assembled distinct microbial communities and increased total enzyme activity, leading to significant improvement of soil physicochemical traits. The increased availability of soil nutrient thus changed leaf nutrient concentrations and alleviated the early defoliation rate of pear trees in acid red soil in southern China.

Isolation and Screening of Pectinase Producing Bacteria from Soil Sample

The vast majority of the industrial use of enzymes is covered from microorganisms. Microorganisms are favoured in industry because of their several advantages for example rapid growth, short life expectancy and simplicity in doing genetic alterations. Microbial enzymes are thus amply provided, very much standardized and promoted by many companies. Among various enzymes, Pectinases hold an exceptional place because of its different uses in various sectors like food, textile and biofuel industries.A total of 25% of total enzyme market is being shared by Pectinase alone.The current study was carried out to evaluate the pectinase activity of the pectinolytic bacteria. 40 Bacterial strains were isolated from different soil samples and screened for Pectinase production. Primary and Secondary screening showed 3 potential isolates I38 , I39 and I40 showing pectin degradation on Vincent’s media. Further, extracellular pectinase was partially purified by ammonium sulphate precipitation and dialysis. Sequential ammonium sulphate saturations from 20-80% i.e. (20, 40, 60 and 80%) showed 60% ammonium sulphate was optimum for precipitation of intracellular enzyme whereas 80% was optimum for extracellular enzyme.

Immobilization of Crude Polyphenol Oxidase Extracts from Apples on Polypyrrole as a Membrane for Phenol Removal

This research aims to make a polypyrrole (PPy) membrane and crude extract of polyphenol oxidase (PPO) as a membrane of mPPy/PPO apple extracts. The membrane of PPy/PPO-apple extract has been synthesized by the electrodeposition method. The electrolyte composition consists of a mixture of 0.10-0.20 M pyrrole (Py) and 50-100% PPO apple extract, which is stable using 50 mM of phosphate buffer solution at pH 6.80-7.00 and room temperature. The electrodeposition process is used 400 mesh steel gauze anode ST-304 and carbon plate cathode. Electrodeposition is carried out at potential = 5.00-6.00 V; current = 0.02-0.25 A; the distance from both electrodes = 1.00-2.00 cm for 300-500 seconds. The results from the deposition of PPy/PPO apple extract of the anode are a membrane of mPPy/PPO-apple extract, with total enzyme activity (U) = (957,1441, 2287 and 1754) using 2.00-5.00 mM phenol as a substrate which is measured based on the UV-visible spectrophotometric method. PPy and mPPy/PPO-apple extracts were characterized by SEM and SEM-EDS. The membrane of mPPy/PPO-apple extract can be used to remove phenol in industrial wastewater samples is 50-65% with a filtration capacity of 500 mL for 2 hours.

Variable accumulation of cadmium in flax (Linum usitatissimum L.)

Given the potential use of flax in metal-contaminated soil remediation programs, the uptake and accumulation of cadmium was studied in five varieties of flax (Linum usitatissimum L.) including var. Belinka, Escalina, Jitka, Marina and Krasnoder. Early stage plants in hydroponics were exposed to Cd to assess their tolerance by means of growth parameters and content of photosynthetic pigments. All varieties exerted tolerance indexes in the range of 63 – 89 %, while oxidative stress was not detected in either variety. Chitinase enzymes were analyzed in leaf protein extracts since activities of these enzymes have previously been correlated with plant tolerance to Cd. However, total enzyme activities remained unchanged in presence of Cd in all flax varieties. A more detailed analysis of these enzymes identified up to 3 chitinase isoforms upon separation of leaf protein extracts in polyacrylamide gels, and their quantification confirmed responsiveness to Cd for each of them. The obtained data were interpreted in light of metal uptake rate, which we measured using gammaspectrometry in growth media spiked with 109Cd and in the plant tissue. The variety Jitka showed the most sensitive to Cd and accumulating fast and the highest amounts of metal. In contrast, the variety Belinka appeared most tolerant, accumulating the least Cd in a slow rate. Activation of chitinase isoforms correlated with more sensitive varieties and suggests activation of general defense mechanisms. The obtained data suggest the variety Jitka as most promising for phytoremediation programs and the var. Belinka as the most suitable when avoidance of potential health risk is of interest.

Total Enzyme-substrate Complex Which Includes Product-destined Enzyme-substrate Complex

Background: There is no much interest in the determination of total enzyme-substrate complex concentration ([ES]T) which includes undissociated ES that is unaccounted for unlike the usual ES destined for transformation into free enzyme and product or substrate. The reason is speculatively as a result of the lack of awareness of such possibility via sequestration. Objectives: 1) To derive on the basis of both reverse – and standard – quasi-steady – state assumptions equations for the determination of [ES]T which is not restricted to the complex which dissociates to product/substrate and free enzyme and 2) quantitate the value of [ES]T. Methods: A theoretical research and experimentation using Bernfeld method to determine velocities of amylolysis with which to calculate relevant parameters. Results: The [EST] is < [E] ( i. e. [ET] - [ES]); [EST] decreased with increasing [ST] and increased with increasing concentration of enzyme [ET] while the velocity of amylolysis, v and maximum velocity of amylolysis, vmax expectedly increased with increasing [ET] and [ST]. Conclusion: The equations for the determination of the total enzyme-substrate complex, free enzyme without any complex formation before and after dissociation of enzyme-complex into product and/or substrate and free enzyme were derived. The difference, [ET] - [ES] is a heterogeneous mixture of undissociated ES and free enzyme without any complex formation. This is the case because [ES] which dissociates into product is only a part of the total enzyme-substrate complex. There is a continuous formation of ES during and at the expiry of the duration of assay as long as there is no total substrate depletion.

Two-Step Production of Neofructo-Oligosaccharides Using Immobilized Heterologous Aspergillus terreus 1F-Fructosyltransferase Expressed in Kluyveromyces lactis and Native Xanthophyllomyces dendrorhous G6-Fructosyltransferase

Fructo-oligosaccharides (FOS) are prebiotic low-calorie sweeteners that are synthesized by the transfer of fructose units from sucrose by enzymes known as fructosyltransferases. If these enzymes generate β-(2,6) glycosidic bonds, the resulting oligosaccharides belong to the neoseries (neoFOS). Here, we characterized the properties of three different fructosyltransferases using a design of experiments approach based on response surface methodology with a D-optimal design. The reaction time, pH, temperature, and substrate concentration were used as parameters to predict three responses: The total enzyme activity, the concentration of neoFOS and the neoFOS yield relative to the initial concentration of sucrose. We also conducted immobilization studies to establish a cascade reaction for neoFOS production with two different fructosyltransferases, achieving a total FOS yield of 47.02 ± 3.02%. The resulting FOS mixture included 53.07 ± 1.66 mM neonystose (neo-GF3) and 20.8 ± 1.91 mM neo-GF4.

MODELO MATEMÁTICO PARA LA TRANSFRUCTOSILACIÓN DE ESTEVIÓSIDO CON - FRUCTOFURANOSIDASA INMOVILIZADA

MODELO MATEMÁTICO PARA LA TRANSFRUCTOSILACIÓN DE ESTEVIÓSIDO CON - FRUCTOFURANOSIDASA INMOVILIZADA MATHEMATICAL MODEL FOR TRANSFRUCTOSYLATION OF STEVIOSIDE USING ImmOBILIZED - FRUCTOFURANOSIDASE Fiorella Cárdenas T. Departamento de Ingeniería Química, Universidad de Tohoku, Japón DOI: https://doi.org/10.33017/RevECIPeru2010.0002/ RESUMEN En el presente articulo, un modelo matemático fue diseñado para la transfructosilación de esteviósido con b-fructofuranosidasa inmovilizada considerando el equilibrio de partición entre la fase liquida y la fase de partícula, difusión y reacción dentro de la partícula. Las constantes cinéticas fueron estimadas mediante el ajuste de las ecuaciones cinéticas con los resultados experimentales de la síntesis de fructosil-esteviósido con enzima libre. Las otras constantes fueron estimadas mediante el ajuste del modelo matemático con resultados experimentales de coeficiente de equilibrio de partición, y síntesis de fructosil-esteviósido con enzima inmovilizada. El modelo describe la formación de fructosil-esteviósido en el tiempo para varias condiciones de concentración inicial de sustrato y enzima total en el sistema. Palabras clave: transfructosilación, fructosil-esteviósido, análisis cinético, modelo matemático. ABSTRACT In the present article, a mathematical model for the b- immobilized fructofuranosidase was constructed considering the partition equilibrium between the liquid phase and the particle, diffusion and reaction within the particle. The kinetic constants were estimated by fitting the kinetic equations with the experimental data of the fructosyl-stevioside experiments using suspended enzyme. The other constants were estimated by fitting the mathematical model with experimental data of partition equilibrium coefficient, and fructosyl-stevioside synthesis using immobilized enzyme. The model could describe the fructosyl-stevioside formation under several conditions of initial concentration of substrate and total enzyme in the system. Keywords: Transfructosilation, fructosyl – stevioside, kinetic analysis, mathematical model.