Optimization of growth medium for the production of α‐amylase from Bacillus amyloliquefaciens using response surface methodology

The optimization of nutrient levels for the production of α‐amylase by Bacillus amyloliquefaciens was carried out using response surface methodology (RSM) based on the 2³ factorial central composite design (CCD). This procedure limited the number of actual experiments performed while allowing for possible interactions between three components. RSM was adopted to derive a statistical model for the effect of starch, peptone and yeast extract (YE) on α‐amylase production. The P‐value of the coefficient for linear effects of starch and YE concentration was <0.0001, suggesting that this was the principal experimental variable, having the greatest effect on the production of α‐amylase. The optimal combinations of media constituents for maximum α‐amylase production were determined as 12.61 g L^?1 starch, 2.83 g L^?1 peptone and 1.25 g L^?1 YE. The optimization of the medium resulted not only in a 34% higher enzyme activity than unoptimized medium but also in a reduced amount of the required medium constituents. Copyright © 2006 Society of Chemical Industry     

Optimization of medium and process parameters for a constitutive α‐amylase production from a catabolite derepressed Bacillus subtilis KCC103

BACKGROUND: In Bacillus subtilis KCC103 α‐amylase is hyper‐produced and not catabolite repressed by glucose. Various sugars, raw starches and nitrogen sources were tested for their repression effect on α‐amylase synthesis. Enhancement of α‐amylase production by supplementing micronutrients and surfactants was studied. Using optimized medium, process parameters were optimized for improved α‐amylase production. RESULTS: α‐Amylase was produced from KCC103 utilizing simple sugars indicating the absence of catabolite repression. Raw potato and yeast extract were best carbon and nitrogen sources for α‐amylase production. α‐Amylase synthesis was enhanced by micronutrients cysteine, thiamine, Mg²⁺ and SDS. Maximum α‐amylase (394 IU mL^?1) was produced in the optimized medium consisting of (in g L^?1) raw potato (30.0), yeast extract (20.0), cysteine (0.3), thiamine (0.2), SDS (0.2) and MgSO₄ (0.5 mmol L^?1) at 36–48 h under optimal conditions (pH 7.0, 37 °C, 200 rpm). The α‐amylase production was further enhanced to 537.7 IU mL^?1 with shorter time (15–18 h) in a bioreactor with optimized agitation rate of 700 rpm at 30% dissolved oxygen. CONCLUSION: Since there was no carbon catabolite repression of α‐amylase synthesis, sugar mixture from various agro‐residues hydrolysates could be utilized for α‐amylase production. The study showed the feasibility of utilization of raw potato for α‐amylase production from the KCC103, which would lead to a significant reduction in process cost. Copyright © 2008 Society of Chemical Industry     

Optimization of agro‐residual medium for α‐amylase production from a hyper‐producing Bacillus subtilis KCC103 in submerged fermentation

BACKGROUND: Although submerged fermentation (SmF) is the conventional method in industry, use of low‐cost agro‐residues for α‐amylase production in SmF has not been well established. Here we optimized agro‐residue‐based medium and culture conditions for α‐amylase production in SmF using a hyper‐producing Bacillus subtilis KCC103. RESULTS: B. subtilis KCC103 produced α‐amylase in SmF by utilizing agro‐residues. Wheat bran (WB) and sunflower oil cake (SFOC) were selected as the best substrates using shake flasks. Medium containing WB (carbohydrate rich) and SFOC (rich in protein and free amino acids) at 1:1 (w/w) ratio produced high levels (90 IU mL⁻¹) of α‐amylase at 30–36 h in a shake flask. The α‐amylase yield was 14‐fold enhanced (1258 IU mL⁻¹) by optimizing process parameters and medium composition following response surface methodology in a bioreactor. The optimal conditions were: WB 1.27%, SFOC 1.42%, pH 7, 37 °C and 10–12 h. Both in shake flask and bioreactor α‐amylase synthesis was not repressed by the release of simple sugars into the medium. CONCLUSION: KCC103 with catabolite derepression and hyperproducing ability is useful for economic α‐amylase production using low‐cost agro‐residual substrates in conventional SmF. Since the production time (10–12 h) is much shorter than other strains this would improve productivity and further reduce the cost of α‐amylase production. Copyright © 2008 Society of Chemical Industry     

Optimization of medium for phenylalanine ammonia lyase production in <Emphasis Type="Italic">E. coli</Emphasis> using response surface methodology

A culture medium for phenylalanine ammonia lyase (PAL) production in E. coli was developed following preliminary studies by means of response surface methodology (RSM). The medium components having significant effect on the production were first identified by using a fractional factorial design. Then, central composite design (CCD) was used to optimize the medium constituents and explain the combined effects of four medium constituents: glucose, yeast extract, (NH₄)₂HPO₄ and MgSO₄. A quadratic model was found to fit the PAL production. CCD revealed that the optimum values of the test variables for PAL production were glucose 28.2 g/L, yeast extract 5.01 g/L, (NH₄)₂HPO₄ 7.02 g/L and MgSO₄ 1.5 g/L. PAL production of 62.85 U/g, which was in agreement with the prediction, was observed in the verification experiment. In comparison to the production of basal medium, 1.8-fold increase was obtained.     

Optimization of medium components for D-ribose production by transketolase-deficient <Emphasis Type="Italic">Bacillus subtilis</Emphasis> NJT-1507

Statistical experimental designs were used to optimize the composition of culture media for the production of D-ribose by Bacillus subtilis. A fractional factorial design 2^(5-2) was used to determine medium components that significantly affected D-ribose production. The concentrations of glucose and (NH₄)₂SO₄ were the significant factors. Central composite design and response surface methodology were then used to estimate the quadratic response surface and determine the factor levels for maximum production of D-ribose. Finally, the optimal medium composition was obtained (g/L): glucose, 172.75; (NH₄)₂SO₄, 13.2; yeast powder, 4; corn steep liquor, 8 and MnSO₄, 0.5. This optimization strategy increased D-ribose production from 73.21 g/L to 88.57 g/L, an increase of 22% compared with the original conditions. The D-ribose production yield to glucose concentration was also enhanced from 0.37 g/g to 0.52 g/g. Confirmatory experiments were also performed to demonstrate the accuracy of the model. Under the optimal medium using ammonia to control pH in a 5 L fermenter, the D-ribose yield was increased to 95.28 g/L after 3 days of cultivation at 37 °C.     

Production of α‐amylase under solid‐state fermentation utilizing coffee waste

Coffee industry substrates such as coffee pulp, coffee cherry husk, silver skin, spent coffee and mixtures of these coffee wastes (MC) were evaluated for their efficacy as sole carbon source for the synthesis of α‐amylase in solid‐state fermentation (SSF) using a fungal strain of Neurospora crassa CFR 308. For SSF with coffee pulp and with MC, α‐amylase activity of 3908 U g^?1 ds (units per gram of dry substrate) and 3870 U g^?1 ds, respectively, was observed. Parameters such as moisture (60%), pH (4.6), temperature (28 °C), particle size (1.0 mm), inoculum size (10⁷ spores g^?1 ds), and fermentation time (5 days) were optimized for enzyme synthesis, wherein 4981 and 4324 U g^?1 U g^?1 ds of α‐amylase activity was obtained in SSF with coffee pulp and MC, respectively. The enzyme production was further improved when the substrates were subjected to pre‐treatment by steaming. Accordingly, maximum α‐amylase activity of 7084 U g^?1 ds and 6342 U g^?1 ds was obtained with steam‐pretreated coffee pulp and MC, respectively, demonstrating them to be excellent sole carbon sources for synthesis of α‐amylase production. Copyright © 2009 Society of Chemical Industry     

Kinetics of the thermal inactivation of Bacillus subtilis α‐amylase and its application on the desizing of cotton fabrics

The thermal inactivation of Bacillus subtilis α‐amylase was studied in the presence and in the absence of Ca²⁺ at various temperatures. Inactivation rate constant (k), half‐life time (t_1/2), and activation energy (E_a) were determined to characterize the inactivation of the enzyme. Results obtained showed that the thermal inactivation of Bacillus subtilis α‐amylase followed a first‐order kinetics. The addition of Ca²⁺ had a good thermostabilizing effect on the enzyme. The stabilizing effect of Ca²⁺ is reflected by the increased values of the activation energy, which is about two times higher in the presence than that in the absence of 20 mM Ca²⁺, and the decreased values of the inactivation rate constants. The desizing of the cotton fabrics was performed through steaming at 100°C with Bacillus subtilis α‐amylase. The desizing efficiency seemed to be dependent on the concentration and pH value of the enzyme solution. It was found that through the steaming process with α‐amylase, the desizing ratio of the cotton fabrics could be beyond 98% and little damage happened to the fibers of the fabrics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Catalytic Hydrogenation of Chiral α‐Amino and α‐Hydroxy Esters at Room Temperature with Nishimura Catalyst without Racemization

The hydrogenation of carboxylic acid derivatives at room temperature was investigated. With a mixed Rh/Pt oxide (Nishimura catalyst), low to medium activity was observed for various α‐amino and α‐hydroxy esters. At 100 bar hydrogen pressure and 10% catalysts loading, high yields of the desired amino alcohols and diols were obtained without racemization. The most suitable α‐substituents were NH₂, NHR, and OH, whereas β‐NH₂ were less effective. Usually, aromatic rings were also hydrogenated, but with the free bases of amino acids as substrates, some selectivity was observed. No reaction was found for α‐NR₂, α‐OR, and unfunctionalized esters; acids and amides were also not reduced under these conditions. A working hypothesis for the mode of action of the catalyst is presented.     

Optimization of salts in medium for production of carboxymethylcellulase by a psychrophilic marine bacterium, <Emphasis Type="Italic">Psychrobacter aquimaris</Emphasis> LBH-10 using two statistical methods

The concentration of four mineral salts in the medium for the production of carboxymethylcellulase (CMCase) by Psychrobacter aquimaris LBH-10 were optimized using orthogonal array method (OAM) and response surface method (RSM) and their results from two statistical methods were compared. The analysis of variance (ANOVA) of data from central composite design (CCD) based on OAM indicated that potassium phosphate gave the highest percentage participation for cell growth as well as production of CMCase. However, their relative participations of four salts for cell growth were different from those for production of CMCase. The ANOVA of results from RSM indicated that highly significant factors (“probe>F” less than 0.0001) for cell growth were K₂HPO₄ and (NH₄)₂SO₄, whereas those for production of CMCase were K₂HPO₄, NaCl, and MgSO₄·7H₂O. The optimal concentration of K₂HPO₄, NaCl, MgSO₄·7H₂O, and (NH₄)₂SO₄ for cell growth extracted by Design Expert Software based on RSM were 7.10, 0.84, 0.24, and 0.33 g/L, respectively, whereas those for production of CMCase were 3.00, 0.52, 0.34, and 0.45 g/L. The optimal concentrations of salts for cell growth and production of CMCase using RSM basically coincided with those using OAM as well as those from ‘one-factor-at-a-time’ method. The production of CMCase by P. aquimaris LBH-10 with optimized concentrations of salts was 273.0 U/mL, which was enhanced by 1.27 times higher than the previous report.     

Composition optimization of poly(vinyl alcohol)‐/cornstarch‐blended biodegradable composite using response surface methodology

Response surface methodology was used to analyze the effect of amylase level (X₁) and glycerol level (X₂) on the objective [water solubility index (WSI), water absorption index (WAI), and Max. loading] attributes of a poly(vinyl alcohol)‐/cornstarch‐blended composite. A rotable central‐composite design (CCD) was used to develop models for the objective responses. The experiments were run at die temperature 100°C with a feed rate of 25 g/min and a screw speed of 35 rpm. Responses were most affected by changes in the amylase level (X₁) and to a lesser extent by glycerol level (X₂). Individual contour plots of the different responses were overlaid, and regions meeting the optimum WSI of 3.03 (%), WAI of 5.08 (g gel/g dry wt), and Max. loading of 29.36 (N) were identified at the amylase level of 2.8 (mL) and the glycerol level of 92.2 (mL), respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Determination of optimal conditions for ribonucleic acid production by <Emphasis Type="Italic">Candida tropicalis</Emphasis> no. 121

The experiments were based on multivariate statistical concepts, and response surface methodology (RSM) was applied to optimize the fermentation medium for the production of ribonucleic acid (RNA) by Candida tropicalis no. 121. The process involved the individual adjustment and optimization of various medium components at shake flask level. The two-level Plackett-Burman (PB) design was used to screen the medium components, which significantly influenced RNA production. Among seven variables, the concentrations of molasses, ZnSO₄, and H₃PO₄ were found to be the important factors that significantly affected RNA production (confidence levels above 95%). These factors were further optimized using a central composite design (CCD) and RSM. The optimum values for the critical components were as follows: molasses 47.21 g/L: ZnSO₄ 0.048 g/L; H₃PO₄ 1.19 g/L. Under optimal conditions, RNA production was 2.56 g/L, which was in excellent agreement with the predicted value (2.561 g/L), and led to a 2.1-fold increase compare with that using the original medium in RNA production.     

α‐Amylase immobilized by Fe3O4/poly(styrene‐co‐maleic anhydride) magnetic composite microspheres: Preparation and characterization

Fe₃O₄/poly(styrene‐co‐maleic anhydride) core–shell composite microspheres, suitable for binding enzymes, were prepared using magnetite particles as seeds by copolymerization of styrene and maleic anhydride. The magnetite particles were encapsulated by polyethylene glycol, which improved the affinity between the magnetite particles and the monomers, thus showing that the size of the microspheres, the amount of the surface anhydrides, and the magnetite content in the composite are highly dependent on magnetite particles, comonomer ratio, and dispersion medium used in the polymerization. The composite microspheres, having 0.08–0.8 μm diameter and containing 100–800 μg magnetite/g microspheres and 0–18 mmol surface‐anhydride groups/g microsphere, were obtained. Free α‐amylase was immobilized on the microspheres containing reactive surface‐anhydride groups by covalent binding. The effects of immobilization on the properties of the immobilized α‐amylase [magnetic immobilized enzyme (MIE)] were studied. The activity of MIE and protein binding capacity reached 113,800 U and 544.3 mg/g dry microspheres, respectively. The activity recovery was 47.2%. The MIE had higher optimum temperature and pH compared with those of free α‐amylase and showed excellent thermal, storage, pH, and operational stability. Furthermore, it can be easily separated in a magnetic field and reused repeatedly. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 328–335, 2005     

The effects of culture condition on the growth property and docosahexaenoic acid production from Thraustochytrium aureum ATCC 34304

The effect of the composition of artificial sea water (ASW) medium on the growth properties and docosahexaenoic acid (DHA) production from Thraustochytrium aureum ATCC 34304 was investigated. A maximum dry cell weight (DCW) of 3.71 g/l was obtained when the NaCl and MgSO₄ concentration in the ASW media were 15 and 0 g/l, respectively. The maximum initial specific growth (ISG) rate of 0.16 was attained at 7.5 g/l NaCl and 18 g/l MgSO₄, while the minimum ISG rate (0.02) was obtained at 5.0 g/l NaCl and 4.5 g/l MgSO₄. The least doubling time required for biomass production was 4.3 h at 7.5 g/l NaCl and different MgSO₄ concentrations. A maximum of 7.9 g/l DCW was obtained on the fourth day of cultivation at 30 g/l glucose and 2.5 g/l (each) yeast extract (YE) and peptone. The DHA content in the lipids was significantly affected by the concentration of glucose and nitrogen sources (YE and peptone) in the ASW medium. At the lowest glucose (10 g/l) and YE/peptone (0.5 g/l) concentration and highest glucose (30 g/l) and YE/peptone (2.5 g/l) concentration, the DHA content was 34.725 and 40.33%, respectively, relative to total lipid content. However, the DHA content in the lipid was not affected by the NaCl and MgSO₄ concentration. At the lowest NaCl (2.5 g/l) and MgSO₄ (4.5 g/l) concentration and highest NaCl (60 g/l) and MgSO₄ (18 g/l) concentration the DHA content was 39.62 and 38.48%, respectively. The maximum DHA content in the lipid was 49.01% after four days of cultivation when 7.5 g/l NaCl and 4.5 g/l MgSO₄ were in the ASW medium. The growth properties of T. aureum ATCC 34304 for biomass production and DHA yield in the lipid content were found to be affected by NaCl and glucose concentration.     

Synthesis,characterization, and corrosion inhibition study of polyaniline‐α‐Fe2O3 nanocomposite

Polyaniline (PANI)‐α‐Fe₂O₃ nanocomposites (NCs) have been synthesized by chemical oxidative in situ polymerization of aniline in presence of α‐Fe₂O₃ nanoparticles at 5°C using (NH₄)₂S₂O₈ as an oxidant in an aqueous solution of sodium dodecylbenzene sulphonic acid (SDBS), as surfactant and dopant under N₂ atmosphere. The room temperature conductivity of NCs decreases and coercive force (H_c) increases with an increase addition of α‐Fe₂O₃ in PANI matrix. The result of FTIR and TGA shows that the interaction between α‐Fe₂O₃ particles and PANI matrix could improve the thermal stability of NCs. NCs demonstrate the superparamagnetic behavior. The performance of PANI and PANI‐α‐Fe₂O₃ NCs as protective coating, against corrosion of 316LN stainless steel in 3.5% NaCl was assessed by potentiodynamic polarization technique. The study shows a good corrosion inhibition effect of both the coatings. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Production of poly‐3‐hydroxybutyrate by Cupriavidus necator from corn syrup: statistical modeling and optimization of biomass yield and volumetric productivity

BACKGROUND: The paper reports an investigation into the possibility of producing poly‐3‐hydroxybutyrate (P(3HB)) polyester using corn syrup, a relatively low cost by‐product from the starch industries. The concentrations of medium components, corn syrup, dipotassium hydrogen phosphate (K₂HPO₄), sodium dihydrogen phosphate (NaH₂PO₄) and ammonium sulfate [(NH₄)₂SO₄] were optimized using design of experiments (DOE). RESULTS: Response surface methodology (RSM) under central composite face design (CCFD) was used to obtain the optimum values of medium components and responses in terms of biomass yield and volumetric P(3HB) productivity. The highest P(3HB) productivity and biomass yield obtained were 0.224 g L^?1 h^?1 and 0.57 g g^?1, respectively. A limited‐nitrogen concentration had a higher volumetric P(3HB) productivity (0.170 g L^?1 h^?1) than that of the excess nitrogen batch experiment (0.0675 g L^?1 h^?1). The optimum corn syrup:N:P ratio of 50:0.078:1 was based on numerical optimization of the desirability function between biomass yield and volumetric P(3HB) productivity by Cupriavidus necator DSMZ 545. CONCLUSION: The results obtained in this study demonstrated that P(3HB) could be efficiently produced to a high concentration with high productivity by applying nitrogen limitation in a defined medium, indicating this agricultural by‐product to be a suitable nutrient source in further studies to develop biomaterials through biotechnology. Copyright © 2010 Society of Chemical Industry     

Application of statistical experimental design for optimization of physiological factors and their influences on production of pullulan by <Emphasis Type="Italic">Aureobasidium pullulans</Emphasis> HP-2001 using an orthogonal array method

Physiological factors for the production of pullulan by A. pullulans HP-2001 were optimized using orthogonal array method and their influences were compared using Qualitek-4 software. The analysis of variance (ANOVA) indicated that the most important factor for cell growth was yeast extract, whereas that for production of pullulan was glucose. The optimal conditions for cell growth were found to be 100.0 g/L glucose, 10.0 g/L yeast extract, and initial pH of 6.0, whereas those for the production of pullulan were 100.0 g/L glucose, 2.5 g/L yeast extract, and initial pH of 5.5. Among four mineral salts in the medium, potassium phosphate (K₂HPO₄) was found to be the most important factor for cell growth as well as production of pullulan. Next important salt for cell growth was (NH₄)₂SO₄, whereas that for production of pullulan was NaCl. The optimal concentrations of K₂HPO₄, NaCl, MgSO₄·7H₂O, and (NH₄)₂SO₄ for cell growth were 7.5, 1.00, 0.1, and 1.20 g/L, respectively, whereas those for production of pullulan were 2.5, 0.25, 0.8, and 0.30 g/L. The expected cell growth and the production of pullulan by A. pullulans HP-2001 under these optimized conditions were 12.61 and 11.49 g/L, respectively.     

Optimal culture condition for the production of phenyalanine ammonia lyase from <Emphasis Type="Italic">E. coli</Emphasis>

The effects of culturing conditions on phenylalanine ammonia lyase production by a recombinant E. coli strain were investigated by using a controlled fed-batch fermentation system. In a 5 L fermentor, the optimal composition of the batch medium was 2% glucose, 1% yeast extract, 0.7% K₂HPO₄, 0.8% KH₂PO₄, 0.5% (NH₄)₂SO₄, 0.1% MgSO₄·7H₂O. The optimal feed glucose solution was 50%. Glucose concentration and pH of the culture broth were maintained at about 2.0 g/L and 7.0 during the fed-batch phase, respectively. Following 24-h cultivation, 0.2 mmol/L isopropyl-β-D-thiogalactopyranoside (IPTG) was added and temperature was shifted from 37°C to 42°C to induce pal gene expression. Under optimal conditions, a high productivity of 300 U/g could be achieved after 48 h culture, and a cell density of OD₆₀₀ about 82 was obtained at 52 h culture at 500 r/m stirrer speed and 1 vvm, respectively.     

Extraction of zinc from blast‐furnace dust using ammonium sulfate

The reaction between roasted zinc blast‐furnace dust (BFD) and ammonium sulfate was studied in the temperature range 250–450 °C using different molar ratios to determine the maximum extraction of zinc. The reaction products are characterized. The composition of the untreated and roasted BFD, and reaction products was investigated by chemical, thermal, X‐ray diffraction and fluorescence analyses. The decomposition of ammonium sulfate leads to the formation of (NH₄)₂S₂O₇, NH₄HSO₄ and (NH₄)₃H(SO₄)₃. The main zinc reaction products are ZnSO₄, ZnSO₃, (NH₄)₂Zn(SO₄)₂, (NH₄)₂Zn₂(SO₄)₃ and (NH₄)₂Zn₄(SO₄)₅. The reaction mechanisms of these formations are discussed in detail. The identity of these products depends essentially on the temperature as well as the molar ratios of the reactants. The optimum conditions for the formation of soluble zinc compounds are molar ratio 1:8 of roasted zinc dust (ZnO) and (NH₄)₂SO₄ at 350 °C. Under these conditions, up to 95% of zinc was leached with 0.5 M sulfuric acid. Copyright © 2004 Society of Chemical Industry     

Effect of surfactants on α‐amylase production in a solid substrate fermentation process

Solid substrate fermentation (SSF) is a process where the substrate is a moist solid, which is insoluble in water but not suspended in water. In this study SSF of Bacillus subtilis (ATCC 21556) was used to produce an enzyme of commercial importance, α‐amylase, using as a substrate potato peel. To enhance the production of this enzyme, two nonionic synthetic surfactants were used, Tween 80 and Tween 20, one anionic surfactant, SDS at concentrations of 0.05% and 0.10% (v/w) and a biosurfactant produced by Bacillus subtilis (ATCC 21332), known as surfactin, at concentrations of 0.003%, 0.007%, 0.013% and 0.03% (w/w). The results have shown that surfactants significantly increase the production of α‐amylase. Tween 80 at 0.10% and surfactin at 0.013% provided the highest enzyme activity when compared with the control. © 1999 Society of Chemical Industry     

Characterization of products of interaction between kaolin ore and ammonium sulphate

The reaction products resulting from the interaction between kaolin ore and ammonium sulphate depend on molar ratios between reactants, reaction temperature and time of interaction. The reaction products were characterized by means of XRD. They were composed of silica, unreacted kaolin ore, traces of iron, magnesium, calcium, titanium and NH₄Al(SO₄)₂ and (NH₄)₃Al(SO₄)₃. The last compound was produced alone at 553 K, whereas mixtures of them were produced between 553 and 823 K after a short time of interaction (0.5 h). On other hand the former compound was produced alone after longer heating (c. 2 h). At 823 K, a mixture composed of Al₂(SO₄) and NH₄Al(SO₄)₂ was identified after 0.5 h, whereas anhydrous aluminium sulphate was detected alone after heating the reaction mixture for 2 h. The transformation of (NH₄)₃Al(SO₄)₃ into NH₄Al(SO₄)₃ and alumina leads to a decrease in the percentages of extracted alumina from kaolin ore at relatively higher temperatures and/or longer heating of reaction mixtures. The investigation was also devoted to establishing the possible reactions which lead to the formation of Fe₂O₃, MgO, CaO and TiO₂ as soluble salts together with aluminium compounds. The percentages of their extraction are low compared with the original quantities found in kaolin ore. From the obtained results, both Al₂(SO₄)₃ and NH₄Al(SO₄)₂ can be prepared from local kaolin with a reasonable degree of purity which makes it possible to produce them for use for different industrial and pharmaceutical purposes.