Tratamiento de agua contaminada con metales pesados utilizando como medios filtrantes biorresina intercambiadora de cationes de la cáscara y tallo de guineo y carbón activado de endocarpo de coco / Treatment of contaminated water with heavy metals, utilizing as filtering media a cation exchanger bio-resin from the banana peel and bush and activated carbon from coconut endocarp

En este trabajo de desarrollo experimental, la Escuela de Ingeniería Química de ITCA-FEPADE se propuso comprobar la efectividad de las cáscaras y pseudotallo de guineo y el endocarpo de coco, previamente tratados, para remover la contaminación por metales pesados en una muestra de agua. Para tal objeto, se procesaron dichas biomasas para ser utilizadas como medios filtrantes, los cuales se caracterizaron por medio de pruebas físicas: densidad y tamaño de partícula. Se evaluó su efectividad para remover metales, filtrando agua contaminada con cantidades conocidas de metales pesados tales como hierro, cromo y níquel (Fe3+Cr6+ y Ni2+), variando el tiempo de contacto y el tipo de medio filtrante. La cuantificación de los metales en el agua tratada se llevó a cabo por espectrofotometria de absorción atómica: para el níquel (λ = 232.0 nm); hierro (λ = 24830 nm) y cromo hexavalente (λ = 357.9 nm). Además, se determinó el color en los filtrados por el método de platino-cobalto. Se llegó a la conclusión que las biomasas utilizadas en este estudio resultaron efectivas para la disminución de metales pesados y color en la muestra de agua sintética elaborada en el laboratorio.

In this experimental development work, the Escuela de Ingeniería Química ITCA-FEPADE set out to verify the effectiveness of previously treated banana peels and pseudostem and endocarp to remove heavy metal contamination in a water sample. For this purpose, said biomasses were processed to be used as filter media, which were characterized by means of physical tests: density and particle size. Its effectiveness to remove metals was evaluated, filtering water contaminated with known amounts of heavy metals such as iron, chromium and nickel (Fe3 + Cr6 + and Ni2 +), varying the contact time and the type of filter medium. The quantification of the metals in the treated water was carried out by atomic absorption spectrophotometry: for nickel (λ = 232.0 nm); iron (λ = 24830 nm) and hexavalent chromium (λ = 357.9 nm). In addition, the color in the filtrates was determined by the platinum-cobalt method. It was concluded that the biomasses used in this study were effective in reducing heavy metals and color in the synthetic water sample prepared in the laboratory.

Tratamiento de agua contaminada con metales pesados, utilizando como medios filtrantes bio-resina intercambiadora de cationes de la cáscara y mata de guineo y carbón activado de endocarpo de coco / Treatment of contaminated water with heavy metals, utilizing as filtering media a cation exchanger bio-resin from the banana peel and bush and activated carbon from coconut endocarp

En este trabajo de desarrollo experimental, la Escuela de Ingeniería Química de ITCA-FEPADE se propuso comprobar la efectividad de las cáscaras y pseudotallo de guineo y el endocarpo de coco, previamente tratados, para remover la contaminación por metales pesados en una muestra de agua. Para tal objeto, se procesaron dichas biomasas para ser utilizadas como medios filtrantes, los cuales se caracterizaron por medio de pruebas físicas: densidad y tamaño de partícula. Se evaluó su efectividad para remover metales, filtrando agua contaminada con cantidades conocidas de metales pesados tales como hierro, cromo y níquel (Fe3+Cr6+ y Ni2+), variando el tiempo de contacto y el tipo de medio filtrante. La cuantificación de los metales en el agua tratada se llevó a cabo por espectrofotometria de absorción atómica: para el níquel (λ = 232.0 nm); hierro (λ = 24830 nm) y cromo hexavalente (λ = 357.9 nm). Además, se determinó el color en los filtrados por el método de platino-cobalto. Se llegó a la conclusión que las biomasas utilizadas en este estudio resultaron efectivas para la disminución de metales pesados y color en la muestra de agua sintética elaborada en el laboratorio.

In this experimental development work, the Escuela de Ingeniería Química at ITCA-FEPADE set out to verify the effectiveness from the banana peels and pseudostem and also the coconut endocarp, previously treated, to remove heavy metals contamination from a water sample. For this purpose, said biomasses were processed to be used as filtering media, which were characterized through diverse physical tests: density and particle size. Its effectiveness to remove metals was evaluated by filtering water contaminated with known quantities of heavy metals such as iron, chromium and nickel (Fe3+, Cr6+ y Ni2+), varying the contact period of time and the filtering medium type. The quantification of the metals in the treated water was carried out with atomic absorption spectrophotometry: for nickel (λ = 232.0 nm); iron, (λ = 248.3 nm) and hexavalent chromium, (λ =357.9 nm). In addition, the color of the filtered was determined through the platinum-cobalt method. It was concluded that the biomasses used in this study resulted to be effective to reduce heavy metals and color from the synthetic water sample made in the laboratory.

Elaboración de bio-resina intercambiadora de cationes a partir de cáscara de plátano o guineo para eliminar metales pesados en agua contaminada / Manufacture of cation exchange bio-resin from banana peel to remove heavy metals in contaminated water

Esta investigación tuvo por objetivo obtener una bio-resina intercambiadora de cationes utilizando cáscaras de guineo o plátano, la cual reduzca la concentración de metales pesados en agua contaminada. A esta bio-resina se le realizaron pruebas fisicoquímicas: densidad seca aparente, pH y solubilidad en agua y solventes orgánicos. Se evaluó su efectividad filtrando agua contaminada con metales pesados, tales como hierro, cromo y níquel (Fe3+, Cr6+ y Ni2+), variando las condiciones de tiempo de contacto, temperatura y el tipo de cáscara. La cuantificación de la concentración de los metales en el agua filtrada se llevó a cabo por espectrofotometría visible. Se llegó a la conclusión que la bio-resina obtenida es efectiva para disminuir la concentración de metales pesados en agua, teniendo especial afinidad química por el cromo hexavalente; metal pesado que logró remover arriba del 90%. Las condiciones óptimas de operación de la bio-resina son a 30°C y 90 minutos de tiempo de contacto con la muestra. Además, las pruebas fisicoquímicas, permitieron tipificarla preliminarmente como una resina de intercambio catiónico débil con un grado de entrecruzamiento bajo.

The objective of this research was to obtain a cation exchange bio-resin using banana peels, which reduces the concentration of heavy metals in contaminated water. Physicochemical tests were carried out on this bio-resin: apparent dry density, pH and solubility in water and organic solvents. Its effectiveness was evaluated by filtering water contaminated with heavy metals, such as iron, chromium and nickel (Fe3 +, Cr6 + and Ni2 +), varying the conditions of contact time, temperature and the type of shell. The quantification of the metal concentration in the filtered water was carried out by visible spectrophotometry. It was concluded that the bio-resin obtained is effective in reducing the concentration of heavy metals in water, having a special chemical affinity for hexavalent chromium; heavy metal that was able to remove over 90%. The optimal operating conditions for the bio-resin are at 30 ° C and 90 minutes of contact time with the sample. Furthermore, physicochemical tests allowed it to be preliminarily typified as a weak cation exchange resin with a low degree of crosslinking.

Preparation and quality assessment of high-purity ginseng total saponins by ion exchange resin combined with macroporous adsorption resin separation / 中国天然药物

AIM@#To prepare high-purity ginseng total saponins from a water decoction of Chinese ginseng root.@*METHOD@#Total saponins were efficiently purified by dynamic anion-cation exchange following the removal of hydrophilic impurities by macroporous resin D101. For quality control, ultrahigh-performance liquid chromatography with a charged aerosol detector (CAD) was applied to quantify marker components. The total saponin content was estimated by a colorimetric method using a vanillin-vitriol system and CAD response.@*RESULTS@#D201, which consisted of a cross-linked polystyrene matrix and -N(+)(CH3)3 functional groups, was the best of the four anion exchange resins tested. However, no significant difference in cation exchange ability was observed between D001 (strong acid) and D113 (weak acid), although they have different functional groups and matrices. After purification in combination with D101, D201, and D113, the estimated contents of total saponins were 107% and 90% according to the colorimetric method and CAD response, respectively. The total amount of representative ginsenosides Re, Rd, Rg1, and compound K was approximately 22% based on ultrahigh-performance liquid chromatography-CAD quantitative analysis.@*CONCLUSION@#These findings suggest that an ion exchange resin, combined with macroporous adsorption resin separation, is a promising and feasible purification procedure for neutral natural polar components.

Study on preparation and property of a new adsorbent for endotoxin removal in blood purification / 生物医学工程学杂志

In order to remove the endotoxin from the blood of endotoxemia patients, we prepared a new adsorbent with heparin space arm and polymyxin B (PMB) ligand. The carrier of chloromethyl polystyrene resin was activated and heparin space arm was grafted, and then PMB ligand was immobilized onto adsorbent with glutaraldehyde. We employed in vitro FITC-lipopolysaccharide (FITC-LPS) static adsorption to characterize the adsorption properties on the adsorbent, and conducted in vitro lipopolysaccharide (LPS) static adsorption to measure quantitavely the adsorption capacity and rate, and then evaluated the blood compatibility. The in vitro static adsorption indicated that the adsorbent had the removal rate of LPS above 70% with the adsorption equilibrium time for 2 hours. Blood compatibility experiment showed that the adsorbent had little negative effects on blood cells and plasma protein, and their adsorption rates were less than 10% for hemocytes and 20% for plasma protein respectively. This adsorbent exhibited high selectivity, high adsorption capacity and good biocompatibility, and presented a promising clinical application in the treatment of endotoxemia.

Development and evaluation of ofloxacin orally disintegrating tablets

Bitter taste of ofloxacin, a broad spectrum bactericidal agent, is masked and orally disintegrating tablets were formulated. The bitter taste is masked by forming complex between drug and weak cation exchange resins, Tulsion 335 and Indion 204. Effect of pH and drug:resin ratio on the drug loading was studied. Maximum drug loading was observed at pH 6. Ratio of 1:2 of drug:resin masked almost complete bitterness of ofloxacin. Formation of complexes was confirmed by IR spectroscopy. Physical characterization of taste masked complexes was carried out. Present work envisages the taste masking of ofloxacin and development of orally disintegrating tablets. The effect of pH and resin quantities on drug loading were studied to find the optimum conditions of drug loading for complete taste masking. Effect of superdisintegrants like sodium starch glycolate, croscarmellose sodium and polyplasdone XL at varying level on physical parameters of compressed tablets was also assessed. The formulations containing 5 % w/w polyplasdone XL showed about 90 % of drug release within 5 minutes. No significant differences were observed in the physical parameters of resinates as well as tablets prepared from Tulsion 335 and Indion 204.

O gosto amargo de ofloxacina, agente bactericida de largo espectro, é mascarado e formularam-se comprimidos dispersíveis. O sabor amargo é mascarado pela formação de complexo entre o fármaco e resinas de troca catiônica fraca, Tulsion 335 e Indion 204. Efeito do pH e da proporção fármaco: resina sobre a carga de fármaco foi estudada. Carga de fármaco máxima foi observada em pH 6. Proporção 1:2 do fármaco: resina mascarou quase completamente o gosto amargo de ofloxacina. A formação de complexos foi confirmada por espectroscopia no IV. Caracterização física dos complexos de sabor mascarado foi realizada. O presente trabalho preconiza o mascaramento do gosto de ofloxacina e desenvolvimento decomprimidos por via oral, se desintegrando. O efeito do pH e da resina quantidades de carga de fármaco foram estudadas paraencontrar as condições óptimas de carga de fármaco para dissimulação do saborcompleto. Efeito da superdisintegrants como amido glicolato de sódio, croscarmelose sódica e Polyplasdone XL em diferentes níveis de parâmetros físicos de comprimidos também avaliados foi avaliada. As formulações contendo 5 %w/w Polyplasdone XL mostraram cerca de 90% de libertação do fármaco no prazo de 5 minutos. Não foram observadas diferenças significativas nos parâmetros físicos de resinatosbem como comprimidos preparados a partir de Tulsion 335 e Indion 204.

Contamination mechanism and regeneration strategies of chromatographic resin in separation process for expression product from mammary gland bioreactor / 生物工程学报

This study focused on the contamination mechanism and regeneration strategies of sulfopropyl ion exchange resin (SP Sepharose FF) during the separation of recombinant human lactoferrin from transgenic bovine milk. We analyzed primary constituents' contents in chromatorgraphic material and fractions. The results showed that the lipid in milk can clog the column or adhere to the resin through hydrophobic interaction, leading to an increase in column pressure. Some casein molecules were found to adsorb onto the resin through electrostatic interaction, therefore the adsorption capacity was decreased. There was no direct interaction between lactose and the resin in the chromatorgraphic process. Increased continuous chromatographic cycles and prolonged time interval between protein purification and column regeneration could enhance the undesirable interaction between the contaminants and resin, thus lowering the regeneration efficiency. NaOH was found to be effective in the removal of lipid and casein molecules from the column. Furthermore, normal microstructure and chromatographic performance of the ion exchanger was recovered after this cleaning procedure.

Novel ion exchange resin-based combination drug-delivery system for treatment of gastro esophageal reflux diseases

The present study involves preparation and characterization of a combination tablet of ranitidine in immediate release form and domperidone in sustained release form, using ion exchange resins. Ranitidine lowers acid secretion, while domperidone release over a prolonged period improves gastric motility thus justifying this combination in gastro esophageal reflux diseases (GERD) and ensuring patient compliance. Drug loading was carried out by batch method & resinates were characterized using FTIR, XRPD. Resinates were formulated as a combination tablet and evaluated for tablet properties & in vitro drug release. Resinates provided sustained release of domperidone and immediate release of ranitidine. IR and X-ray studies indicate complexation of drug and resin along with monomolecular distribution of drugs in amorphous form in the resin matrix. The tablets of resinate combination showed good tablet properties. In-vitro drug release gave desired release profiles and ex-vivo drug absorption studies carried out by placing everted rat intestine in dissolution medium indicated statistically significant similarity in absorption from test and marketed formulation. The novelty of this study is that the retardation in release of domperidone from resinates is achieved by presence of weak resin in the formulation.

O presente estudo envolve a preparação e a caracterização de associação do comprimido de ranitidina de liberação imediata e domperidona de liberação prolongada, utilizando resinas de troca iônica. A ranitidina diminui a secreção ácida, enquanto a liberação prolongada de domperidona melhora a motilidade gástica, justificando, dessa forma, a associação em doenças de refluxo gastroesofágico (DRGE) e garantindo a adesão do paciente. A carga de fármaco foi efetuada pelo método em batelada e os resinatos, caracterizados utilizando-se FTIR e XRPD. Os resinatos foram formulados como comprimido da associação e avaliados com relação às propriedades dos comprimidos e liberação do fármaco in vitro. Os resinatos proporcionaram a liberação prolongada da domperidona e a liberação imediata da ranitidina. IV e estudos de difração de raios X indicaram a complexação do fármaco e da resina junto com a distribuição monomolecular dos fármacos, em estado amorfo, na matriz da resina. Os comprimidos da associação do resinato apresentaram boas propriedades. Obtiveram-se os perfis de liberação in vitro e os estudos de absorção dos fármacos ex vivo realizados com intestino de rato em meio de dissolução indicaram semelhança significativa na absorção entre as formulações teste e comercializada. A inovação do trabalho é que o retardamento da liberação da domperidona dos resinatos é atingido pela presença de resina fraca na formulação.

Removal of chromium [VI] from aqueous solutions using lewatit FO36 nano ion exchange resin

The removal of the chromium [VI] ion from aqueous solutions with the Lewatit FO36 ion-exchange resin is described at different conditions. The effects of adsorbent dose, initial metal concentration, contact time and pH on the removal of chromium [VI] were investigated. The batch ion exchange process was relatively fast and it reached equilibrium after about 90 min of contact. The ion exchange process, which is pH dependent showed maximum removal of chromium [VI] in the pH range 5.0-8.0 for an initial chromium [VI] concentration of 0.5 mg/dm[3]. The equilibrium related to Lewatit FO36 ion- exchange capacity and the amounts of the ion exchange were obtained using the plots of the Langmuir adsorption isotherm. It was observed that the maximum ion exchange capacity of 0.29 mmol of chromium [VI]/g for Lewatit FO36 was achieved at optimum pH value of 6.0. The ion exchange of chromium [VI] on this cation-exchange resin followed first-order reversible kinetics

Immobilization of Candida sp. lipase on resin D301 / 生物工程学报

We immobilized Candida sp. lipase onto seven kinds of industrial adsorption and ion exchange resins. By determining the activity of each immobilized enzyme, the weakly basic anionic exchange resin of D301 showed the best results for the immobilization of Candida sp. lipase. Comparing the scanning electron micrographs of D301 with Novozym 435 (immobilized Candida antarctica lipase B from Novo Nordisk Corp.), we selected D301 as a carrier for the immobilization of Candida sp. lipase. And we pretreated the resin D301 with the bifunctional agent glutaraldehyde and crosslinked it with Candida sp. lipase. The optimal conditions for the immobilization of Candida sp. lipase were as follows: 8 mL of the amount of 5% glutaraldehyde solution, five hours of the time pretreated D301 with glutaraldehyde, 1.0 g/L the concentration of Candida sp. lipase used, pH of the phosphate buffered, 6.0 and 10 hours of time for immobilization, respectively. The activity of immobilized enzyme was over 35 U/mg and the efficiency of immobilization was around 3.5 Ul(mg x h).

Decolorization and purification of total leaves saponins of panax notoginseng with ion exchange resins / 中国中药杂志

The total leaves saponins of panax notoginseng decoloring by adsorption with exchange resins was studied and the decoloring capacity of six anions resins as adsorbent material was evaluated. The decoloring capacity of the selected resins (D296 and Dt) was compared by the dynamic adsorption decolorization experiments. Removel of coloured compounds in rew solution takes place in two serially coupled different ionic exchange columns, one packed column was D72 cation resin, another anion resin. The results showed that macroporous anion exchange resin Dt was the best resin to decolorization of the total leaves saponins of panax notoginseng. The total saponin products with higher purity and quality were obtained. The results of this work shows that the method proposed is convenient, high efficcient and steady one.

Optimization of a novel mucoadhesive drug deliver system with ion-exchange resin core loaded with berberine hydrochloride using central composite design methodology / 药学学报

A novel mucoadhesive microcapsule with drug-resin complex core loaded with berberine hydrochloride (BH) was developed and optimized. Drug-ion exchange resin (IER) complex was prepared by static method which stirring IER in drug solution at certain conditions. The influences of different IERs, different temperature, pH values and concentrations of drug solution on the drug loading were investigated. IER complex was coated by emulsion-solvent evaporation method. The coating fluid formulation was optimized using central composite design-response surface methodology, where the ratio between Carbopol 934 and IER (X1), the ratio between Eudragit and IER (X2) and the ratio between Eudragit RL and RS (X3) were taken as independent variables. Time of cumulative release 85% (Y1) and percentage of gastric retention (Y2) were taken as response variables. Drug loading achieved a high level and more drug available in the condition of IER (IRP 88), 37 degrees C, pH 5 and 1.0 mg x mL(-1) drug solution. When X1 = 0.75, X2 = 0.9, X3 = 0.6, the time of cumulative release reached 85% at 300 min, the highest percentage of gastric retention in the range of this experiment were procured.

Softeners for hardness removal.

The depletion of water resources, both surface and subsurface and deterioration of water quality made researchers and policy makers to think of the possible remedies to make water sources potable / wholesome. There is a need to address the problems of hardness and fluoride in subsurface water on priority basis. In this direction, bench scale studies were conducted to evaluate the performance of water softeners. Indepth studies were carried out at University B.D.T College of Engineering, Davangere, Karnataka, to assess the performance of bench scale softeners of D to H ratio 1:2, 1:3, 1:4 in removing hardness of varied concentrations from both synthetic and natural water samples. Studies revealed that irrespective of D to H ratio of softeners, the waters having hardness concentration up to 1000 mg/l can be treated to the same degree (81.68% and above). The findings of regeneration studies and cost economics are also summarized in this paper.

A new configuration of membrane stack for retrieval of nickel absorbed in resins / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

A new configuration integrated ion exchange effect system with both electro-migration and electrochemical reaction in a single cell was developed to effectively retrieve metal ions from simulated wastewater using ion exchange resins without additive chemicals. By simply assembling cation exchange resins and anion exchange resins separated by homogeneous membranes, we found that the system will always be acidic in the concentrate compartment so that ion exchange resins could be in-situ regenerated without hydroxide precipitation. Such a realizable design will be really suitable for wastewater purification.

The qualitative analysis and quantitative analysis of purification of salvianolic acids by macroreticular resin / 中国中药杂志

<p><b>OBJECTIVE</b>To purify salvianolic acids by macroreticular resin,then mensurate the contents of salvianolic acids and analyse the chromatogram with HPLC.</p><p><b>METHOD</b>Make salvianolic acids with macroreticular resin; mensurate the content of Salvianolic acids with UV spestrophotometry: the control compound is protocaechuic aldehyde, and the wavelength is 281 nm. Analysis the chromatogram with HPLC, and compare the chromatogram in different technics: zorbax ODS column (4.6 mm x 250 mm, 5 microm), mobilephase: 1% aceticacid-water and methanol in different proportions, the wavelength is 281 nm.</p><p><b>RESULT</b>The contents of salvianolic acids is 53.8%; HPLC chromatogram indicate that the method is reasonable to make salvianolic acids.</p><p><b>CONCLUSION</b>Determination of contents and HPLC chromatogram can control the quality of Salvianolic acids more accurately.</p>

Contaminação das águas subterrâneas por nitrato em Presidente Prudente - SP, Brasil / Nitrate contamination in grounwater in Presidente Prudente-SP, Brazil

A pesquisa teve como objetivo delimitar zonas de contaminação das águas subterrâneas por nitrato na área urbana de Presidente Prudente-SP, Brasil, verificar a sua possível relação com a expansão da urbanização e apontar prováveis causas do fenômeno a ser caracterizado. Os trabalhos executados incluíram a consulta aos arquivos do Instituto Adolfo Lutz com referência a análises físico-químicas de águas subterrâneas, alocalização dos pontos de coleta de amostras pelo sistema de coordenadas UTM, o tratamento geoestatístico dos dados das análises por meio do Programa Surfer-Surface Mapping System, com a interpolação por Krigagem linear. Este mapeamento realça a localização da contaminação em áreas bem definidas, estando os poços contaminados em zona inscrita na área de ocupação urbana anterior ao ano de 1962. Como fontes da contaminação, a pesquisa executada distingue o vazamento de esgoto doméstico, a lixiviação de fossas e a lixiviação de depósitos variados de resíduos sólidos. Os resultados das análises evidenciam também a resina de troca iônica, cujo emprego se tem mostrado eficiente

Resinas de intercambio iónico para prolongar la liberación de los fármacos / Ion-exchange resins for prolonged release of drugs

Se realizó el estudio de las resinas de intercambio iónico como sistemas para liberación prolongada con atención a los factores que afectan la formación de los resinatos o complejos fármacoresina. También se estudió la liberación de los principios activos a partir de los complejos y de las formas terminadas que los contienen, evaluándose los factores que afectan dicho proceso y las cinéticas a las que se ajusta. Se revisaron las combinaciones de procesos tecnológicos (principalmente la formación de complejos iónicos y su recubrimiento) que potencian la utilidad de los resinatos para prolongar la liberación a través de mecanismos combinados de intercambio iónico y difusión a través de membranas, combinaciones dirigidas a reducir las limitaciones inherentes a cada proceso por separado y conseguir un control eficaz de la liberación de fármacos iónicos

Fermentation and recovery of L-glutamic acid from cassava starch hydrolysate by ion-exchange resin column

Investigators were carried out with the aim of producing L-glutamic acid from Brevibacterium sp. by utilizing a locally available starchy substrate, cassava (Manihot esculenta Crantz). Initial studies were carried out in skate flasks, which showed that even though the yield was high with 85-90 DE (Dextrose Equivalent value), the maximum conversion yield (-34 per cent) was obtained by using only partially digested starch hydrolysate, i.e. 45-50 DE. Fermentations were carried out in batch mode in a 5 L fermenter, using suitably diluted cassava starch hydrolysate, using a 85-90 DE value hydrolysate. Media supplemented with nutrients resulted in an accumulation of 21 g/L glutamic acid with a fairly high (66,3 per cent) conversation yield of glucose to glutamic acid (based on glucose consumed and on 81,74 per cent theoretical conversion rate). The bioreactor conditions most conductive for maximum production were pH 7.5, temperature 30§C and an agitation of 180 rpm. When fermentation was conducted in fed-batch mode by keeping the residual reducing sugar concentration at 5(per cent) w/v, 25,0 g/L of glutamate was obtained after 40 h fermentation (16 per cent more the batch mode). Chromatographic separation by ion-exchange resin was used for the recovery and purification of glutamic acid. It was further crystallized and separated by making use of its low solubility at the isoelectric point (pH 3.2).