Use Of Ammonium Sulfate Research Articles

Influence of the Use of Ammonium Sulfate and Citric Acid on the Buoyancy of Minerals in Copper-cobalt Plant Process (Case of 635 Deposit Fed at Kambove

The objective pursued in this work is testing the performance of two new reagents namely ammonium sulfate and citric acid, on buoyancy of Kamfundwa ore currently treated at Kambove Concentrator. Optimization tests were conducted in order to determine the optimal doses of reagents commonly used, in this case Sodium hydrosulfide (NaSH), the amylxanthate potassium (KAX), Sodium silicate (Na2SiO3), and the mixture fuel-fatty acid. Metallurgical results obtained with these tests were used as reference for further work. Tests with citric acid alone could not improve the metallurgical results obtained under standard conditions, the same finding was observed in tests with ammonium sulfate alone and that performance seemed to be much closer to those of reference tests. We finally realized flotation tests by combining citric acid and ammonium sulfate in order to streamline the synergy of these two reagents. It appears from these tests that at the dose of 600 g / t of citric acid and 400 g / t of ammonium sulfate, metallurgical performance obtained are better than previously. The following results were achieved during the batch flotation tests: 18.87% as copper content of the head concentrate, with a recovery rate of 55.34%, and 10.81% as copper content of the global concentrate; for a copper recovery corresponding to 80.94%. This mixture of citric acid and ammonium sulfate has allowed good selectivity and a reduction of gangue trained to the concentrate.

Desiccation and senification in the technology of cultivation of winter triticale varieties in the Middle Urals

Triticale is an artificially man-made culture that has both positive and negative signs and properties. One of such undesirable signs is the low resistance of the grain to germination during maturation. Therefore, the search for ways to reduce this phenomenon is an urgent issue. Pre-harvest treatment of crops, namely desiccation and senification, can be a solution to this problem. The purpose of the study, conducted in the conditions of the Udmurt Republic, geographically belonging to the Middle Urals, was a comparative study of the effect of desiccation and senification of crops on yield and grain quality of winter triticale. In a two-factor field experiment during the growing seasons 2021 and 2022, the varieties Izhevskaya 2 (control) and Beta, whose crops were treated with desiccant Sukhovey and seni- cants – 20 and 30% solutions of ammonium nitrate and ammonium sulfate, were studied. In the years of the study, the final stages of ontogenesis in triticale varieties took place in hot dry conditions. As a result, the effect of the studied substances did not affect the grain yield. When comparing the declared varieties, the yield advantage of the Beta variety was established due to the formation of larger grains and higher inflorescence productivity. At the same time, a greater accumulation of dry matter per unit area was characterized by a higher-growing variety Izhevskaya 2. In the course of the experiment the increase of the natural weight indices of winter triticale variety Beta by 7–9 g/l in the variants with the use of ammonium sulfate was revealed. Grain volume weight of the Izhevskaya 2 variety did not change under the influence of the studied methods.

Agro-technologies for greenhouse gases mitigation in flooded rice fields for promoting climate smart agriculture

We investigated methane (CH4) and nitrous oxide (N2O), two important greenhouse gases (GHGs) emissions using the closed chamber method from a flooded rice field in Brahmaputra valley of Assam, northeast part of India. We tried to understand the factors responsible for the emission and identify appropriate agro-technologies for their mitigation. Various factors like water level, drainage management, soil organic carbon management, crop management, fertilizer amendment, cultivar type etc. affect the GHG production and emission from the flooded rice soil. In this study, six treatments were employed, namely, farmer's practice (FP), recommended fertilizer dosage (RDF), direct seeded rice (DSR), intermittent wetting drying (IWD), use of efficient methanotrophs (MTH), and use of ammonium sulfate as a nitrogen source for real-time nitrogen management using leaf color chart, (AS). GHG flux was measured through the static closed chamber technique. Soil temperature, pH, and redox potential (Eh) and other soil physico-chemical and biological properties that have a potential role in GHG emission were also assessed. The lowest CH4 flux was observed in IWD treatment. The highest CH4 but lowest N2O flux was observed in RDF thus portraying a tradeoff relationship among these two GHGs. The highest N2O flux was observed in AS. Changes in Eh strongly altered CH4 and N2O emissions. The CH4 flux for the growing season varied from 62.5 to 86.3 kg ha−1 with an average of 72.4 kg ha−1. The average N2O flux was 0.89 kg ha−1 with values fluctuating between 0.72 – and 1.08 kg ha−1. The findings of this study could assist in understanding the factors affecting the source, production, and sink of these two important GHGs. IWD, along with judicious N-based fertilizer use, could provide significant respite from GHG emissions in rice-based agriculture. These climate-smart strategies not only reduce emissions but also have the potential to improve yield.

Accumulation and Potential Remediation of Copper in Golf Course Putting Greens

The objective of this study was to determine the potential accumulation of copper (Cu) within a USGA golf green profile and analyze potential remediation techniques of soils containing toxic Cu concentrations. Accumulation study utilized: copper phthalocyanine pigment (Par), copper hydroxide (Junction DF), varying concentrations of copper sulfate (CuSO4) within irrigation, and combinations of each. Products were applied over 13 weeks at Clemson University horticulture greenhouses with samples taken at thatch depth, 0-5.1 cm below thatch, and 5.1-10.2 cm below thatch at conclusion of study. Average Cu concentrations in thatch layer was 634.7 kg Cu ha-1, with 0 - 5.1 cm and 5.1 - 10.2 cm depth concentrations of 11.26 and 6.84 kg Cu ha-1, respectively. Remediation studies exposed 5 mg Cecil sandy loam to 15 ml 1000 ppm of CuSo4-Cu followed by 4 sequential 20 ml filtration cycles of 1 N ammonium sulfate, 1 N calcium nitrate, 1 N gypsum, or water. Single filtration of ammonium sulfate removed similar or greater amount of Cu than cumulative impact of 4 filtrations of any other products with 2064 mg Cu kg-1. Studies suggest that the management or removal of thatch may alleviate toxic accumulation of copper, however the use of ammonium sulfate in irrigation water may provide additional remediation options to turfgrass managers.

Ammonium sulphate induces dose-dependent ammonium stress in rice seedlings

Plants require nitrogen (N) in various forms to facilitate essential physiological functions. Nitrate (NO3-) is one of the most readily absorbed N forms by plants and is preferred in well-aerated soils because it can be easily transported within the plant. Ammonium (NH4+), on the other hand, is utilized especially in waterlogged or acidic soils, where it is directly absorbed by the roots and incorporated into amino acids. Urea (CH4N2O) is another significant N source found in many fertilizers; it is transformed into NH4+ and nitrate in the soil through microbial processes. These diverse forms of N are crucial for supporting photosynthesis, protein synthesis, and energy production in plants. The escalating use of ammonium sulphate (NH4)2SO4) as a N source in agriculture prompts a thorough examination of its impact on crop health and productivity. This study aimed to investigate the NH4+ toxicity on rice (Oryza sativa) plants by administering various dosages (0 mM, 5 mM, 7 mM, 10 mM, 12 mM, and 15 mM) and assessing their effects on plant growth parameters, particularly root-shoot lengths, root-shoot fresh biomass along with dry weight. Our research utilized a controlled experimental setup to monitor the growth responses of rice plants to these NH4+ concentrations. Results indicated a clear threshold of tolerance, with adverse effects becoming significant at concentrations starting from 7 mM. At this concentration and higher, there was a noticeable decline in root-shoot lengths, root-shoot biomass and dry biomass, marking the onset of toxicity symptoms in rice plants. These findings suggest a critical need for regulated application of (NH4)2SO4 in rice cultivation to avoid detrimental effects on plant health and yield. The study underscores the importance of establishing safe usage guidelines for (NH4)2SO4 in agriculture, ensuring sustainable farming practices while maintaining crop productivity.

Yield and quality of lettuce (Lactuca sativa L.) depending on variety and type of nitrogen fertilizer

The aim of this research was to determine the effect of the application of different types of nitrogen fertilizer in five different varieties of lettuce on yield. The experiment was performed in the open field, in the spring cycle of growing during 2018 and 2019. The size of the base plot was 3 m2, and the trial was set up in a random block system. The trial covered the application of various forms of nitrogen fertilizers: ammonium sulphate, ammonium nitrate and urea. The applied nitrogen dose is 100 kg/ha (May 10th 2018 and May 8th 2019). Samples for the analysis of vitamin C and nitrate content, as well as yield determination, were carried out at the stage of the technological maturity of lettuce (60-62 days after seedling). The average weight of lettuce, depending on the variety, varied in the range of 211.3 g to 258.7 g. The use of ammonium nitrate resulted in the highest average weight of lettuce head (246.7 g), followed by the use of urea (238.9 g) and the lowest by the use of ammonium sulphate (221.0 g). The nutritional value of lettuce (vitamin C content) shows that depending on the applied form of nitrogen in the fertilizer, the highest content of vitamin C was determined by urea (10.86 mg/100 g), then ammonium sulphate (9.61 mg/100 g), and the lowest by ammonium nitrate (7.38mg/100g). The lower content of vitamin C was found in varieties of lettuce with red leaves compared to varieties with green leaves. The accumulation of nitrate in lettuce leaves directly depends on the variety and the applied fertilizer. The highest nitrate content was with ammonium nitrate (2355.6 mg/kg). The accumulation of nitrate in lettuce varieties with red leaves was higher compared to varieties with green leaves. Keywords: Lettuce, Nitrate, Vitamin C, Yield, Open field

Processing of serpentenites of the Arvaten deposit of Uzbekistan with the use of ammonium sulphate

The article presents the results of a study of the processes of obtaining magnesium oxide by fusing serpentinites of the Arvaten deposit in the presence of ammonium sulfate, followed by grinding and treatment with water to separate silica from the suspension, neutralizing the filtrate with ammonia to pH 8.5 for precipitation and separation of impurity metal ions, precipitation and separation of ions magnesium from solution using ammonia and ammonium carbonate, thermal decomposition of magnesium corbanate to obtain magnesium oxide. It has been established that the use of ammonium sulfate for fusion of serpentite at a ratio of serpentenite: (NH4)2SO4 = 100: 201.77 and further processing of the resulting solutions allows you to obtain magnesium oxide with a composition (wt.%): MgO - 97.55; Fe2O3 - 0.86; A12O3 - 0.12; CaO - 0.18; SO3 - 0.48.

Use of ammonium sulphate as a sulphur fertilizer: Implications for ammonia volatilization.

Ammonium sulphate is widely used as a sulphur (S) fertilizer, constituting about 50% of global S use. Within nitrogen (N) management, it is well known that ammonium‐based fertilizers are subject to ammonia (NH3) volatilization in soils with pH > 7, but this has been overlooked in decision making on S fertilization. We reviewed 41 publications reporting measurements of NH3 loss from ammonium sulphate in 16 countries covering a wide range of soil types and climates. In field experiments, loss was mostly <5% of applied N in soils with pH (in water) <7.0. In soils with pH > 7.0, there was a wide range of losses (0%–66%), with many in the 20%–40% range and some indication of increased loss (ca. 5%–15%) in soils with pH 6.5–7.0. We estimate that replacing ammonium sulphate with a different form of S for arable crops could decrease NH3 emissions from this source by 90%, even taking account of likely emissions from alternative fertilizers to replace the N, but chosen for low NH3 emission. For every kt of ammonium sulphate replaced on soils of pH > 7.0 in temperate regions, NH3 emission would decrease from 35.7 to 3.6 t NH3. Other readily available sources of S include single superphosphate, potassium sulphate, magnesium sulphate, calcium sulphate dihydrate (gypsum), and polyhalite (Polysulphate). In view of the large areas of high pH soils globally, this change of S fertilizer selection would make a significant contribution to decreasing NH3 emissions worldwide, contributing to necessary cuts to meet agreed ceilings under the Gothenburg Convention.

RESULTS OF X-RAY PHASE AND IR-SPEC ASE AND IR-SPECTRAL AN TRAL ANALYSIS OF AZOSUPERPHOSPH OSUPERPHOSPHATES OBTAINED ON THE BASIS OF AINED ON THE BASIS OF PHOSPHORITES OF CENTRAL KIZILKUM

This article is devoted to the use of ammonium sulfate in the production of nitrogen-phosphorus fertilizers, which are widely used in agriculture today. In the research work, the possibilities of obtaining azo superphosphate are described in detail by the use of intensive technology based on low-grade phospharites of the Central KyzylKum. X-ray and IRspectroscopic analyzes of a new type of NP-complex fertilizers obtained using a solution of ammonium sulfate in sulfuric acid are described in detail. The X-ray analysis of the obtained sample on the X-ray diffraction pattern of the azo-superphosphate fertilizer revealed the appearance of peaks in the interplanar spacing line (NH4)2SO4 of ammonium sulfate and NH4Н2РO4 of ammonium dihydrogen phosphate. It has been substantiated that in addition to the main nutrient components dicalcium phosphate and monocalcium phosphates, the sample also contains (NH4)2SO4 and NH4Н2РO4. The results of IR spectroscopic analyzes show that the process of decomposition of the CO3 2-ion in the composition of phosphorites, peaks with high intensity formed by stretching vibrations, in the regions of 873.75 and 1417.68 cm-1, were not detected in the IR spectra of the obtained sample and this proves that that the complete decomposition process is complete. Also, the formation of stretching vibrations of the H2PO4-ion - 1215.15 cm-1, the PO4 3-ion - 532.35 cm-1 and bending vibrations of the H2PO4 -ion - 1033.85 cm-1 in the IR spectrum of the sample in this NH4Н2РO4 sample and the formation of stretching vibrations of SO4 2-ion 1436.97 cm-1 confirmed the presence of (NH4)2SO4.

Ways to Reduce the Level of Contamination at the Stages of Tableted Chemical Cholera Vaccine Production

Objective of the study was an assessment of the degree of contamination of cholera chemical vaccine at the stages of preparation and determination of the ways to reduce it.Materials and methods. Liquid and lyophilized components of the cholera chemical vaccine used in the study: cholerogen-anatoxin and O-antigens of Vibrio cholerae 569B and V. cholerae M-41 strains, as well as auxiliary substances (sucrose, talc, calcium stearate, starch). Granulation was carried out in a device that works on a fluidized bed principle, GPCG 2 (GLATT, Germany). Subsequent tabletizing of the mixture was performed using MiniTabT compression machine (LUXNER, Germany). Studies were conducted on the evaluation of “microbiological purity” at the stages of manufacturing of the cholera chemical vaccine, tablets coated with an enteric coating. Positive or negative growth of microorganisms on Petri dishes with nutrient media was determined on visual inspection.Results and conclusions. The dynamics of changes in microbial contamination at certain technological stages of vaccine production has been revealed. It is shown that the solutions of antigens in the process of separation are subject to microbial contamination which is associated with the use of ammonium sulfate during precipitation and non-sterile water at the stage of dialysis. Sterility of semi-finished products has been achieved through twophase filtration of choleragen-anatoxin and sterilization of O-antigens of V. cholerae 569B and V. cholerae M-41 strains with flowing steam at (100±1) °C for 30 minutes. In order to decrease microbial contamination at the stage of granulation additional fine filters were installed in the air-supply system. Further on comparative assessment of microbial purity of vaccine batches obtained using both, direct compression and preliminary granulation, was carried out. It has been experimentally demonstrated that granulation of the components of a tablet mixture of cholera vaccine leads to a decrease in the level of bacterial contamination and improves the microbiological purity of the finished dosage form.

The Utilization of Lamtoro leaves (Leucaena leucocephala L.) Extract as an Alternative Nitrogen Source on The Formation of Nata de Soya Cellulose from Tofu Whey Waste

Nata is not only made from coconut water; it is also possible to produce it from other raw materials. In our study, nata de soya has successfully made using tofu whey as raw material. Research focused is on the utilization of lamtoro (Leucaena leucocephala L.) leaves as an alternative source of nitrogen in addition to the use of ammonium sulphate and urea which have generally been used in nata production. The selected research method was experimental. First, the Lamtoro leaves were mashed and then inserted into the medium and cooked until it boils. The medium was incubated at room temperature for 12-14 days and the thickness of the cellulose was then measured. The purpose of this study was to determine the effect of the using of lamtoro leaf extract (Leucaena leucocephala L.) as an alternative source of nitrogen for nata de soya cellulose formation. The optimization of pH and nitrogen contentration have been obyained. Three types of formula have been arranged, i.e. 1⁄2 of the control nitrogen concentration, equivalent, and 2 times of the control nitrogen concentration, to provide the variation concentration. Results found that the optimum pH was 3 and the optimum nitrogen concentration was ½ of the control nitrogen level. Nata de soya has then prepared using optimum condition of pH and nitrogen concentration. The maximum average of nata de soya thickness was 7.6 mm. In addition to leveraging the ability of medicinal plants and reducing the use of chemicals in the food processing, the use of alternate sources of nitrogen may also be adopted in the wider cellulose nata application.

Continuous culture of Nitrosomonas eutropha and biomethanol production using whole cell biotransformation

AbstractBACKGROUNDNitrosomonas eutropha is a chemolithoautotrophic organism with an ability to oxidize ammonium to nitrite and nitrate. Continuous culture with and without cell recycling was used to enhance production of N. eutropha cell biomass using a 40‐L bioreactor. Whole cell biotransformation was used to convert methane (CH4) present in the biogas into biomethanol using N. eutropha.RESULTSThe maximum biomass production rate of N. eutropha was increased by three‐fold with provision of cell recycling in the continuous culture. Removal of nitrite from the continuous culture resulted in high activity of ammonia monooxygenase enzyme responsible for conversion of CH4 to biomethanol. Use of ammonium sulfate as a source of electrons for biotransformation reaction with N. eutropha resulted in a maximum 119.86 mg L−1 of biomethanol production.CONCLUSIONOur research provides an efficient process for biomass production of N. eutropha using continuous culture. We have demonstrated improvement in CH4 to biomethanol conversion using biogas as feedstock. © 2021 Society of Chemical Industry

Crescimento, qualidade de raízes e atividade da redutase do nitrato em plantas de rabanete submetidas a doses de potássio e fontes de nitrogênio

Nitrogênio e potássio são os nutrientes mais extraídos e exportados pela cultura do rabanete, sendo imprescindíveis para a produtividade e qualidade das raízes produzidas. Desta forma, o presente estudo foi desenvolvido com o objetivo de avaliar alterações no crescimento de plantas e qualidade de raízes de rabanete em função de doses de potássio e fontes de nitrogênio. O experimento foi conduzido em delineamento inteiramente casualizado, com tratamentos arranjados em esquema fatorial 4 x 2, sendo quatro doses de potássio (K), 0, 70, 140 e 210 kg ha-1 de K2O e duas fontes de nitrogênio (N), sulfato de amônio e nitrato de cálcio, com quatro repetições. As plantas foram avaliadas quanto ao crescimento, rendimento, qualidade bioquímica das raízes e atividade da redutase do nitrato nas folhas. Os tratamentos não influenciaram as características de crescimento e rendimento: massa fresca de folhas, massa seca de folhas, área foliar total, comprimento e diâmetro de raiz. A adubação potássica aumentou o conteúdo de vitamina C nas raízes de rabanete e a atividade da redutase do nitrato nas folhas, principalmente quando a fonte de N utilizada foi o nitrato de cálcio. O maior valor de índice SPAD foi obtido na dose de 51 kg ha-1 de K2O. A utilização do sulfato de amônio propiciou maior teor de sólidos solúveis nas raízes.

Free Ammonia Deliming: Effect of Tartaric Acid Addition as a Deliming Agent on The Quality of Wet Blue and Wastewater

The objective of this study was to evaluate the pelt and wastewater characteristics after deliming process in an acid condition by tartaric acid, also wet blue properties that were formed. Various observed variables were the dose of tartaric acid, pelt thickness, calcium content, physical and chemical properties of wet blue, such as tensile strength, tear strength, elongation, shrinkage temperature, and chrome oxide content, as well as the pollutants content of wastewater as chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS), and total dissolve solid (TDS). The experiment used a completely randomized design with a factorial arrangement. The first factor was pH variables consisted of 3 levels, i.e., 4, 5, and 6 in the final deliming solution. The second factor was the deliming time consisted of 3 levels, i.e., 45 min, 60 min, and 75 min. Data were analyzed using Analysis of Variance (ANOVA) and then Duncan’s Multiple Range Test (DMRT). The results showed that deliming for 60 min and the pH of 5 at the end of the solution was the best treatment to remove calcium content in the pelt and reduce the thickness of pelt. It did not affect the physical and chemical quality, such as tensile strength, tear strength, elongation at break, and shrinkage temperature of the wet blue produced. Also, the quality of wastewater produced was better than the use of ammonium sulfate as a deliming agent. It can be concluded that the use of tartaric acid as pH regulator of deliming stage at pH 5 for 60 min can be used as an alternative deliming agent to substitute ammonium sulfate.

The impact of ammonium sulfate and citric acid concentration in print Paste on burn-out degree with Cotton/Polyester fabrics.

The last years of the 20th century have seen real changes and rapid developments in all areas of life, and modern techniques in the field of textile printing have emerged, occupying the first positions in strategic fields. Therefore, this research aims to study the effect of using different concentrations of ammonium sulfate and citric acid in the print paste on the burn-out rate produced on Cotton/polyester blended fabrics in terms of weight loss, tensile strength and elongation to reach the best concentrations that can be used during the burn-out printing process and using it to print ladies' clothing fabrics as one of the most important areas for textile printing designers, as burning printing offers the clothes a unique value that helped to change the course of fashion through the presentation of texture, shape, and appropriateness that The designers dreamed of it. Fabrics used is cotton 100%, polyester 100%, cotton/polyester 35/65, cotton/polyester 50/50, printed in silk screen Research problem: The search problem can be identified in the following question: What are the effect changes resulting from the use of different concentrations of ammonium sulphate and citric acid in the burn-out printing paste and how are they used to produce different texture effects for the production of ladies printed fabrics? Objectives: Study the effect of different concentrations of ammonium sulfate and citric acid in the printing paste on the weight loss ratio of cotton/polyester fabrics and Study the effect of different concentrations of ammonium sulfate and citric acid in the printing paste on the tensile strength and elongation of cotton/polyester fabrics.Significance: Identify the method of burn-out printing as one of the modern methods of printing textiles. Identify the best concentrations that can be used to effect burn-out printing on cotton/poly-esters fabrics. Take advantage of the effect of burning printing in enriching the design of ladies printing fabrics with modern technological thinking and design construction that goes hand in hand with the latest international fashion lines to meet the demands of the consumer. Methodology: The research follows the analytical and experimental descriptive approach by: Analytical descriptive approach: study the effect of the concentrations of ammonium sulphate and citric acid in the burning paste on the characteristics and properties of the printed fabrics. Experimental approach: on the practical side of the experiment using different concentrations of ammonium sulphate and citric acid in the burning paste and use it to print women's fabrics. Results: it was found that: There is a direct correlation between the increase in the rate of burn-out Chemicals in the print paste and the resulting burn-out rate (weight loss). There is a direct correlation between the proportion of cotton in the material to be printed and the resulting burn-out rate. There is an inverse relationship between the concentration of the burn-out Chemicals ratio in the printing paste and the degree of tensile strength and longing of the material. The burn rate resulting from the use of ammonium sulfate is better than the burn rate produced by citric acid. The best concentration for ammonium sulfate is 35g/kg. The best concentration of citric acid is 30g/kg

Purification of (S)-3-cyano-5-methylhexanoic acid from bioconversion broth using an acetone/ammonium sulfate aqueous two-phase system

Abstract (S)-3-Cyano-5-methylhexanoic acid ((S)-CMHA) is the key chiral intermediate of pregabalin. In this paper, an aqueous two-phase system (ATPS) was developed to extract (S)-CMHA from nitrilase-catalyzed bioconversion broth. Inorganic salts and hydrophilic solvents were screened to form ATPS, among which an acetone/ammonium sulfate ATPS was investigated in detail, including phase diagram, effect of phase composition and stability of (S)-CMHA. The maximum product recovery of 99.15% was obtained by an optimized ATPS system composed of 15% (w/w) ammonium sulfate and 35% (w/w) acetone with the removal of 99% cells and 86.27% proteins. The total (S)-CMHA yield reached 92.11% after back-extraction. The recycling use of ammonium sulfate was investigated, and 93.10% of salt in the salt-rich phase was recovered with the addition of methanol. The results demonstrated the efficiency of the two-step extraction process for separation of (S)-CMHA.

Soil acidity, lime application, nitrogen fertility, and greenhouse gas emissions: Optimizing their joint economic management

Soil acidity is a major limiting factor for crop production in many farming systems worldwide. Lime application is the most common practice to mitigate soil acidity. There are complex economic interactions between application of lime and nitrogen fertilizer, with the greenhouse gas emissions associated with the use of these inputs adding further complexity. We employ a non-linear dynamic optimization model to determine economically optimal application strategies for lime and nitrogen fertilizer accounting for the social cost of the resulting emissions of greenhouse gases. The model is applied in three zones with different rainfall levels, in the northern wheatbelt of Western Australia. Rainfall has important influences on results through its effect on the dissolution and leaching of lime, leaching of nitrogen, and the yield potential of crops. Results show that nitrogen-related decisions, such as the type of nitrogen fertilizer and crop rotation, have a substantial impact on optimal lime application rates and resulting emissions. For example, the use of ammonium sulfate, rather than urea, reduces emissions. Similarly, by allowing a reduction in nitrogen fertilizer use the incorporation of legume crops like lupin can reduce emissions by 50%, relative to a wholly non-legume crop rotation. Although carbon pricing reduces emissions, the magnitude of the reductions is modest in all modeled scenarios. The private cost to farmers of a carbon tax in this case study region is small, although the net social benefit of the carbon tax in this case study is smaller still, even without accounting for the transaction costs of operating the tax system.

English

This study was conducted with the objective of evaluating the nitrogen fertilization in orchid seedling formation. The experiment was conducted in a greenhouse environment with a coated polypropylene mesh with retention capacity of 60% of the solar radiation flux at the greenhouse of the Department of Agronomy of State University of Londrina &ndash; PR, Brazil. One year old seedlings of the orchid species Oncidium baueri has been used (Lindl.) from in vitro propagation, with an average height of 8.0 &plusmn; 1.0 cm. The experimental design was completely randomized with four replications and the treatments resulted from a 2&times;7 factorial design in which the factors were two sources (urea and ammonium sulfate) and seven doses of nitrogen applied fortnightly (0.00, 0.75, 1.50, 2.25, 3.00, 3.75, and 4.50 mg/pot). The experiment was conducted for a period of one year and the following variables were evaluated: largest pseudobulb length, plant height, highest root length, leaf area, root number, dry matter, number of leaves, and Dickson quality index. The use of ammonium sulphate resulted in the highest average values to the length of the longest pseudobulb, plant height, leaf area, length of the longest root, and plant dry matter, except for the number of leaves and Dickson quality index. The application of nitrogen between 3.20 and 4.33 mg/pot resulted in the highest values for the length of the longest pseudobulb, number of roots, length of the longest root, number of leaves, plant height and Dickson quality index for O. baueri (Lindl.) orchid. The plant height and leaf area variables increased significantly with increasing doses of N regardless of the source used, but the length of the longest pseudobulb, number of roots and dry matter production of plant only increased when urea was used as a nitrogen source. Key words: Orchidaceae, nitrogen, fertilization, vegetative development. &nbsp

Magnetic Combined Cross-Linked Enzyme Aggregates of Ketoreductase and Alcohol Dehydrogenase: An Efficient and Stable Biocatalyst for Asymmetric Synthesis of (R)-3-Quinuclidinol with Regeneration of Coenzymes In Situ

Enzymes are biocatalysts. In this study, a novel biocatalyst consisting of magnetic combined cross-linked enzyme aggregates (combi-CLEAs) of 3-quinuclidinone reductase (QNR) and glucose dehydrogenase (GDH) for enantioselective synthesis of (R)-3-quinuclidinolwith regeneration of cofactors in situ was developed. The magnetic combi-CLEAs were fabricated with the use of ammonium sulfate as a precipitant and glutaraldehyde as a cross-linker for direct immobilization of QNR and GDH from E. coli BL(21) cell lysates onto amino-functionalized Fe3O4 nanoparticles. The physicochemical properties of the magnetic combi-CLEAs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and magnetic measurements. Field emission scanning electron microscope (FE-SEM) images revealed a spherical structure with numerous pores which facilitate the movement of the substrates and coenzymes. Moreover, the magnetic combi-CLEAs exhibited improved operational and thermal stability, enhanced catalytic performance for transformation of 3-quinuclidinone (33 g/L) into (R)-3-quinuclidinol in 100% conversion yield and 100% enantiomeric excess (ee) after 3 h of reaction. The activity of the biocatalysts was preserved about 80% after 70 days storage and retained more than 40% of its initial activity after ten cycles. These results demonstrated that the magnetic combi-CLEAs, as cost-effective and environmentally friendly biocatalysts, were suitable for application in synthesis of (R)-3-quinuclidinol essential for the production of solifenacin and aclidinium with better performance than those currently available.

Biosynthesis of pyruvic acid from glycerol-containing substrates and its regulation in the yeast Yarrowia lipolytica

The ability of different yeasts to synthesize pyruvic acid (PA) from glycerol-containing substrates has been studied. The selected strain Yarrowia lipolytica VKM Y-2378 synthesized PA with α-ketoglutaric acid (KGA) as a byproduct. The content of KGA greatly depended on cultivation conditions. The minimal formation of the byproduct was provided by the limitation of yeast growth by thiamine (0.6 µg/g biomass); the use of ammonium sulfate (0.6%) as a nitrogen source; addition of glycerol to cultivation medium in 20 g/L portions; maintaining the cultivation temperature at 28 °C, pH of the cultivation medium at 4.5, and medium aeration between 55 and 60% of saturation; the optimal cultivation time was 48 h. The selected strain cultivated under such conditions in a fermenter with a waste glycerol from biodiesel production process synthesized 41 g/L PA with a yield of 0.82 g/g. The mechanism of PA production from glycerol-containing substrates in Y. lipolytica is discussed.