Dissolution kinetics of rare earth metal phosphates in carbonate solutions of alkali metals

Treatment of apatite raw materials is associated with the formation of large-tonnage waste – phosphogypsum. The content of rare earth metals in such waste reaches 1 %, which makes it possible to consider it a technogenic source for obtaining rare earth metals and their compounds. Up to the present moment, there are neither processing plants, nor an efficient process flow to handle phosphogypsum dumps. It is rational to use a way that involves extraction of valuable components and overall reduction of phosphogypsum dumps. Such process flow is available with carbonate conversion of phosphogypsum to alkali metal or ammonium sulfate and calcium carbonate upon the condition of associated extraction of rare earth metal (REM) compounds. Associated extraction of REM compounds becomes possible since they form strong and stable complexes with hard bases according to Pearson, which among other things include carbonate, phosphate and sulfate anions. Formation of lanthanide complexes with inorganic oxygen-containing anions is facilitated by the formation of high-energy Ln-O bonds. The study focuses on the dissolution of lanthanide phosphates in carbonate media. It was established that formation of REM carbonate complexes from their phosphates is a spontaneous endothermic process and that formation of lanthanide carbonates and hydroxides serves as thermodynamic limitation of dissolution. A shift in equilibrium towards the formation of carbonate complexes is achieved by increasing the temperature to 90-100 °C and providing an excess of carbonate. The limiting stage of REM phosphate dissolution in carbonate media is external diffusion. This is indicated by increasing rate of the process with an intensification of stirring, first order of the reaction and the value of activation energy for phosphate dissolution from 27 to 60 kJ/mol. A combination of physical and chemical parameters of the process allowed to develop an engineering solution for associated REM extraction during carbonate conversion of phosphogypsum, which included a 4-5 h conversion of phosphogypsum at temperature of 90-110 °C by an alkali metal or ammonium carbonate solution with a concentration of 2-3 mol/l. As a result, a solution with alkali metal (ammonium) sulfate is obtained, which contains REMs in the form of carbonate complexes and calcium carbonate. The rate of REM extraction into the solution reaches no less than 93 %. Rare earth metals are separated from the mother liquor by precipitation or sorption on anion exchange resins, while the excess of alkali metal or ammonium carbonate is returned to the start of the process.

The properties of rhizobacteria from tomato rhizosphere as biocontrol and biofertilizer

Low soil fertility and the presence of pathogen are the limiting factors in horticultural crops cultivation in Ambon City. This study aimed to isolate plant growth promoting rhizobacteria from tomato rhizosphere as a potential biocontrol, biostimulant and biofertilizer. The research consisted of two stages, namely (1) isolation of bacteria from tomato rhizosphere and purification of the isolates, and (2) characterization of colony morphology, gram reaction, hypersensitivity test and antagonist test to soil pathogens, phosphate dissolution, and phytohormones indole acetic acid (IAA) production. Forty-two isolates were found from tomato rhizosfer, 36 isolates suppressed growth of Rhizoctonia solani while 6 isolates increased the growth of those pathogen. The growth of Phytophthora sp. pathogen was decreased by 35 bacterial isolates and increased by 7 bacterial isolates. All isolates produce IAA but only 13 isolates are enabled to dissolve inorganic phosphate. Based on bacterial properties, the isolates of TT-22, TT-21, TT-12, TT-11, WT-11 and WT-332 are the promising isolates for developing the biological agent as pathogen control and biofertilizer.

Exploring of promising bacteria from the rhizosphere of maize, cocoa and lamtoro

Sukmawati, Ala A, Patandjengi B, Gusli S. 2020. Exploring of promising bacteria from the rhizosphere of maize, cocoa and lamtoro. Biodiversitas 21: 5665-5673. Alginate-producing bacteria are important for improving the quality of dry land, as they can both dissolve phosphate and fix nitrogen. Until now, the alginate-producing bacteria are largely isolated from seaweed. These bacteria were from the root ecosystem of cultivated plants. This study was conducted to explore bacteria that were capable of producing alginates, dissolving phosphates, and fixing nitrogen from the rhizosphere of corn (Zea mays), cocoa (Theobroma cacao), and lamtoro (Leucaena leucocephala). The characterization was carried out both morphologically and physiologically. A total of 17 isolates were successfully grown on alginate media, of which six isolates were from maize rhizosphere, five isolates from cocoa, and six isolates from the lamtoro rhizosphere. Bacterial isolates from the rhizosphere of maize and cocoa varied in terms of colony colors. In contrast, isolates from the lamtoro rhizosphere varied in colony forms. The KK1-40 isolates showed the highest cell biomass and dry weight which were 0.082 g mL-1 and 0.068 g respectively. The KK3-32 isolate showed the highest phosphate dissolution concentration of 10.85 mg L-1 with phosphate solubility efficiency value (PSE) and phosphate solubility index (PSI) which were 166.7 and a phosphate solubility index (PSI) 2.67 with a phosphate dissolution concentration of 10.85 mg L-1. LR1-25 isolates were able to fix the highest amount of nitrogen with a total N content of 0.36%. Isolates KK1-40 and LR1-25 were identified as Gram-negative bacteria and isolate KK-32 were identified as Gram-positive bacteria. The bacterial isolates KK1-40, KK3-32, and LR1-25 were superior bacteria that can be formulated to increase the productivity of dry land.

EKSPLORASI DAN KARAKTERISASI CENDAWAN TANAH PADA RIZOSFER SAWI

ABSTRACTSoil fungis are one of the soil microbes that can be beneficial or detrimental to plants, so they play an important rolein agriculture. This study aims to determine the abundance and characterization of soil fungi in the rhizosphere ofmustard greens. Isolation and identification of soil fungus was carried out in the Pest and Disease Laboratory of theFaculty of Agriculture, University of Borneo Tarakan. The fungus was characterized macroscopically andmicroscopically, and the pathogenicity test, phosphate dissolution activity test, proteolytic activity test and chitinhydrolysis test were carried out. The results of the study obtained 34 fungus colonies. Based on the phenotypiccharacteristics there were 9 fungi isolates with different characteristics, 4 isolates from 9 isolates were non-pathogenic.In non-pathogenic fungi isolates, 2 genera were obtained, namely genus Phialophora sp. and Paecilomyces sp. Thereare non-pathogenic fungus isolates that have proteolytic activity and chitin hydrolysis so that it has the potential as abiological fertilizer and biological agentKeywords: Soil fungis, rhizosphere, characterization ABSTRAK Cendawan tanah merupakan salah satu mikrobia tanah yang dapat bersifat menguntungkan atau merugikan bagitanaman, sehingga berperan penting dalam bidang pertanian. Penelitian ini bertujuan untuk mengetahui kelimpahandan karakterisasi cendawan tanah di daerah rizosfer sawi. Isolasi dan identifikasi cendawan tanah dilakukan diLaboratorum Hama dan Penyakit Fakultas Pertanian Universitas Borneo Tarakan. Cendawan tanah dikarakterisasisecara makroskopis dan mikroskopis, dan dilakukan uji patogenesitas, uji aktivitas melarutkan fosfat, uji aktivitasproteolitik dan uji hidrolisis kitin. Hasil penelitian diperoleh 34 koloni cendawan. Berdasarkan karakteristik fenotipterdapat 9 isolat cendawan dengan karakteristik yang berbeda, 4 isolat dari 9 isolat bersifat non patogen. Pada isolatcendawan yang non patogenik, diperoleh 2 genus yaitu genus Phialophora sp. dan Paecilomyces sp. Isolat cendawannon patogenik yang diperoleh ada yang memiliki aktivitas proteolitik dan hidrolisis kitin sehingga berpotensi sebagaipupuk hayati dan agens hayati. Kata kunci: Cendawan tanah, rizosfer, karakterisasi

The isolation, characterization endophytic bacteria on indole-3-acetic acid-producing and phosphate solubilizing from roots of local rice plant Kamba in Bada Valley, Central Sulawesi

Sudewi S, Ala A, Baharuddin, Farid M. 2020. The isolation, characterization endophytic bacteria on from roots of local rice plant Kamba in Central Sulawesi, Indonesia. Biodiversitas 21: 1614-1624. The local Kamba rice plants are cultivated by the Bada Valley people for generations by obtaining seeds from previous crops. This rice plant is able to survive even though it is cultivated with traditional cultivation techniques. The ability to survive is suspected because this local rice plant is associated with endophytic bacteria through a variety of mechanisms including being able to produce the IAA hormone and its ability to dissolve phosphate. This study aims to find endophytic bacteria that have the potential to produce IAA and phosphate solvents through morphological and physiological characterization (Gram reaction test with 3% KOH, catalase test, hypersensitivity reaction and hemolysis activity), screening of IAA-producing bacteria qualitative and quantitative, phosphate dissolution activity on Pikovskaya medium, and quantitative using a spectrophotometer. Endophytic bacteria isolates from Gintu give the highest yields in IAA production and phosphate solubility activity, namely RKGU11 and RKGU6, respectively at 4,905 mg L-1 and 10.984 mg L-1 so that it has the potential to be used as a candidate for biofertilizer agents in developing effective sustainable agriculture, respectively, efficient and environmentally friendly.

A mathematical model of mitochondrial calcium-phosphate dissolution as a mechanism for persistent post-CSD vasoconstriction

Cortical spreading depolarization (CSD) is the propagation of a relatively slow wave in cortical brain tissue that is linked to a number of pathological conditions such as stroke and migraine. Most of the existing literature investigates the dynamics of short term phenomena such as the depolarization and repolarization of membrane potentials or large ion shifts. Here, we focus on the clinically-relevant hour-long state of neurovascular malfunction in the wake of CSDs. This dysfunctional state involves widespread vasoconstriction and a general disruption of neurovascular coupling. We demonstrate, using a mathematical model, that dissolution of calcium that has aggregated within the mitochondria of vascular smooth muscle cells can drive an hour-long disruption. We determine the rate of calcium clearance as well as the dynamical implications on overall blood flow. Based on reaction stoichiometry, we quantify a possible impact of calcium phosphate dissolution on the maintenance of F0F1-ATP synthase activity.

Phosphate Solvent Fungi Exploration and Identification in West Bali National Park Forest Area

Research on the exploration and identification of phosphate solvent fungi has never been carried out in West Bali National Park (TNBB), therefore researchers aims to explore and identify microscopic fungi to be used as phosphate solvent fungi which later will be taken from each plant soil samples (Lantana camara) that the presence is very common in TNBB. The research was implemented in two stages. The first stage is exploration of soil fungi in the field (TNBB) and identification of fungal species and the second stage is the phosphate solvent fungus test on Pikovskaya media. The results of the identification of the fungi obtained as follow: Aspergillus niger, Aspergillus bertholletius, Aspergillus flavus, Aspergillus isolate 4, Aspergillus isolate 5, Penicillium citrinum, and Trichoderma amazonicum. From the entire types of fungi obtained, there are onlybfour fungi that have the potential as phosphate solvents, namely Aspergillus niger, Aspergillus flavus, Aspergillus bertholletius and Penicillium citrinum with the presence of clear zones on Pikovskaya media. Fungi that has the best potential in the process of phosphate dissolution is Aspergillus niger. Key words: Rhizosfer, Lantana camara, clear zone, phosphate solvent fungus

ISOLASI DAN IDENTIFIKASI BAKTERI PENGHASIL IAA DAN PELARUT FOSFAT DARI RHIZOSFER TANAMAN KELAPA SAWIT

The potential of various genera and species of rhizosphere bacteria is well known. This study aims to determine the diversity and physiological characteristics of the rhizosphere bacterial isolates of oil palm plants at PTPN III Aek Nabara Labuhanbatu North Sumatra. This research was conducted in July 2018 to October 2018 in laboratory of STIPER Labuhanbatu. This research was conducted by isolating bacteria from the root rhizosphere of oil palm plants, characterizing the morphology and physiology of isolates by phosphate dissolution test and indole acetic acid production test. Furthermore, the data was analyzed descriptively. Based on the isolation results obtained 10 bacterial isolates with different macroscopic and microscopic morphological characteristics with the largest amount of dissolved phosphate produced by isolate R05 (0.211 mg / l) and the largest amount of IAA produced by isolate R04 (0.097 mg / l). Isolates R05 and R04 have the potential to be further tested.

Isolasi dan Identifikasi Bakteri Pelarut Fosfat dari Tanah Gambut

Phosphate (P) are macronutrients that necessary for growth and development of plants, But the availability of phosphate dissolved in the ground are very limited because trend is bound to minerals ground form phosphate complexs. One of the alternative to improve the efficiency of phosphate is by utilize phosphate solubilizing bacteria. Phosphate solubilizing bacteria is bacteria capable of dissolving phosphate that is not available become available, so that it can be absorbed by plants. Peat soils can be used as a source of phosphate solubilizing bacteria because , peat soils formed from litter and organic matter so, many microorganisms which live in peat soils one of them is a phosphate solubilizing bacteria. The aim of this research is to isolat, identify bacteria to species level using Biolog system GenIII Mircoplate, and test the ability of phosphate dissolution. The isolation is done with the methods spread plate in a media pikovkaya solid and testing the ability to isolat qualitatively glimpsed clear zone around colonies, measuring phosphate solubilizing index. testing the ability isolats quantitatively by measuring solubility phosphate using spektrofotometer, and identification isolats using Biolog System. Eighteen isolates phosphate solubilizing bacteria successfully obtained from of peat soils, two isolates of them potential in solubilizing phosphate, According to Biolog system the second isolates identified as Pseudomonas tolaasii (isolate PG2T.5) and a Bacillus pumilus (isolate PG3TT.2), each is about phosphate dissolved successive of 24,81 mg/L and 22,62 mg/L Key words: Peat Soil, Isolation, Phosphate Solubilizing Bacteria, Biolog System Identification