Effects of mineral addition on the growth morphology of and arachidonic acid production by Mortierella alpina 1S-4

The culture conditions for arachidonic acid (AA) production by Mortierella alpina 1S-4 were investigated by means of a morphological study with the aims of obtaining a high AA yield and scale-up. In a 50-L jar fermentor study, a medium containing 3.1% soy flour and 1.8% glucose with 0.3% KH₂PO₄, 0.1% Na₂SO₄, 0.05% CaCl₂·2H₂O and 0.05% MgCl₂·6H₂O was found to be optimum. The AA yield reached 9.8 g/L/7 d, and the major morphology was small pellets (1–2 mm). However, in the case of the only addition of KH₂PO₄, the major morphology was filaments. The apparent viscosity increased to 2240 cp, thereby requiring a high agitation speed to maintain adequate oxygen tension, which caused mycelial damage due to shear stress and therefore a decrease in the AA yield. When a medium with Na₂SO₄, CaCl₂, and MgCl₂ was used, the major morphology was large pellets (2–3 mm), and mass transfer limitation through the pellet wall caused a decrease in the AA yield. Based on these results, a scale-up study was carried out under the optimal conditions described above. An AA yield of 10.9 g/L/8 d was obtained in a 10-kL industrial fermentor, and the major morphology was small pellets.     

A comparison of crystal growth kinetics by use of chemical potential difference and concentration difference

A Spherical Void Electrodynanic Levitator Trap (SVELT) was used to measure the water activity in the supersaturated aqueous solutions of six materials, NaCl, (NH₄)₂SO₄, KH₂PO₄, NH₄H₂PO₄, KA1(SO₄)₂ · 12H₂O and glycine. The relationship between chemical potential and concentration was obtained using a fifth order polynomial fit. A comparison of the order of the crystal growth rate obtained from the use of chemical potential difference and concentration difference was made. The order of crystal growth rate calculated from concentration difference was found to be close to that obtained from chemical potential difference at low supersaturation, while at higher supersaturation a deviation was noted.     

Electrochemical behaviour of a vanadium anode in phosphoric acid and phosphate solutions

Anodic polarisation of a vanadium electrode has been studied in H₃PO₄ solutions and some phosphate solutions: LiH₂PO₄, NaH₂PO₄, KH₂PO₄ and NH₄H₂PO₄. The anodic behaviour of a vanadium electrode showed similarities in weak concentrated H₃PO₄, in LiH₂PO₄ and NaH₂PO₄ solutions: the polarisation curve exhibited a current peak followed by current oscillations and then a current plateau. Concentrated H₃PO₄, 1 M KH₂PO₄ and NH₄H₂PO₄ solutions involved vanadium passivation with a very slight current density plateau. Yellow compound identified to VOPO₄·2H₂O was obtained after controlled potential oxidation of vanadium in 5-10 M H₃PO₄. Green products were obtained in 1 M phosphate solutions and in 1-3 M H₃PO₄ on vanadium anode after controlled potential electrolysis. All these vanadophosphate compounds contained the monovalent cation which was present in the solution.     

Mechanochemical synthesis of kaolin-KH2PO4 and kaolin-NH4H2PO4 complexes for application as slow release fertilizer

A milling process to reduce kaolin to amorphous phase in the presence of KH₂PO₄ or NH₄H₂PO₄ and allow mechanochemical (MC) reaction for incorporation of KH₂PO₄ and NH₄H₂PO₄ into the kaolin structure was investigated in this work. Mixtures of kaolin and KH₂PO₄ and NH₄H₂PO₄ in separate systems were prepared by milling in a planetary ball mill. Tests with kaolin contents ranging from 25 to 75 wt.% and mill rotational speeds from 200 to 700 rpm were performed to evaluate incorporation of KH₂PO₄ and NH₄H₂PO₄ and release of K⁺, NH₄⁺ and PO₄³⁻ ions into solution. Analyses by XRD, DTA and ion chromatography indicated that the MC process was successfully applied to incorporate both KH₂PO₄ and NH₄H₂PO₄ into the amorphous kaolin structure. Release of K⁺ and PO₄³⁻ ions from the system (kaolin-KH₂PO₄) when dispersed in water for 24 h reached only up to 10%. Under similar conditions for the system (kaolin-NH₄H₂PO₄), release of NH₄⁺ and PO₄³⁻ ions reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolin to act as a carrier of K⁺, NH₄⁺ and PO₄³⁻ nutrients to be released slowly for use as fertilizer.     

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.     

Utilization of response surface methodology to optimize the culture media for the production of rhamnolipids by Pseudomonas aeruginosa AT10

Pseudomonas aeruginosa AT10 produced a mixture of surface‐active rhamnolipids when cultivated on mineral medium with waste free fatty acids as carbon source. The development of the production process to an industrial scale included the design of the culture medium. A 2⁴ full factorial, central composite rotational design and response surface modelling method (RSM) was used to enhance rhamnolipid production by Pseudomonas aeruginosa AT10. The components that are critical for the process medium were the carbon source, the nitrogen source (NaNO₃), the phosphate content (K₂ HPO₄/KH₂PO₄ 2:1) and the iron content (FeSO₄·7H₂O). Two responses were measured, biomass and rhamnolipid production. The maximum biomass obtained was 12.06 g dm^?3 DCW, when the medium contained 50 g dm^?3 carbon source, 9 g dm^?3 NaNO₃, 7 g dm^?3 phosphate and 13.7 mg dm^?3 FeSO₄·7H₂O. The maximum concentration of rhamnolipid, 18.7 g dm^?3, was attained in medium that contained 50 g dm^?3 carbon source, 4.6 g dm^?3 NaNO₃, 1 g dm^?3 phosphate and 7.4 mg dm^?3 FeSO₄·7H₂O. © 2002 Society of Chemical Industry     

Evaluation and optimization of food-grade tannin acyl hydrolase production by a probiotic Lactobacillus plantarum strain in submerged and solid state fermentation

Tannin acyl hydrolase (tannase) production by Lactobacillus plantarum MTCC1407 was studied in submerged and solid-state fermentation process. Sequential optimization strategy using Plackett–Burman screening and response surface methodology was adopted to optimize the submerged fermentation process. Eight medium components were evaluated initially by Plackett–Burman two level factorial designs to identify the most significant parameters that affect the tannase production. The significant variables affecting tannase production were found to be tannic acid, glucose and MnSO₄·7H₂O. These factors were further optimized by response surface methodology. Maximum tannase activity of 9.13 U ml^?1 was observed at 30 h using the following medium composition (g l^?1): tannic acid, 13.16; glucose, 1.5; NH₄Cl, 1.0; CaCl₂·2H₂O, 1.0; K₂HPO₄, 0.5; KH₂PO₄, 0.5; MgSO4·7H₂O, 0.5 and MnSO₄·7H₂O, 0.03. Among the various carbon sources examined for tannase production by L. plantarum, glucose and tannic acid combination was found to be decisive for enhancing tannase yield. Solid state fermentation was conducted using various solid substrates and agricultural residues. Maximum tannase activity of 5.319 U gds^?1 was obtained using coffee husk as substrate.     

Optimization of arachidonic acid production by Mortierella alpina Wuji-H4 isolate

A fungal isolate Wuji-H4 with a dense-lobe rosette growth pattern on malt extract agar was identified as Mortierella alpina Peyronel. It was capable of producing 504 mg/L of arachidonic acid (AA) in the screening medium. Its AA content accounted for 42.4% of the total fatty acids. The AA yield was raised to 1,817 mg/L by a step-by-step approach, which uncovered that the preferred carbon source, nitrogen source, and temperature for fungal growth and lipid production were soluble starch, urea, and 24°C, respectively. Productivity was further optimized by exploiting the interactions between the constituents of the medium by the response surface method. A partial factorial design, followed by steepest ascent analysis, was carried out to locate the general vicinity of the optimal level of each nutrient. The response surface of AA production in this optimal region was then approximated with a full quadratic equation obtained from a three-factor/five-level central composite rotatable design. Maximum AA yield was predicted to occur in a medium that contained 99.7 g/L of soluble starch, 12.6 g/L of yeast extract, and 3.0 g/L of KH₂PO₄. Upon verification, the average experimental yield of AA (3,885 mg/L) was not significantly different from the predicted AA yield (3,940 mg/L), indicating that the response surface method had succeeded in exploiting the AA production potential of this new fungal isolate.     

Lead immobilization by non-apatite-type calcium phosphates in aqueous solutions

The immobilization of lead (II) ion by β-Ca₃(PO₄)₂, CaHPO₄·2H₂O and Ca(H₂PO₄)₂·H₂O was found to proceed more favorably than that by calcium hydroxyapatite (CaHAp), probably due to rather greater solubility of former three calcium phosphates than that of CaHAp. The contribution of dissolution–precipitation mechanism was suggested to the immobilization.     

Enhancement of polysaccharide production by optimization of culture conditions in shake flask submerged cultivation of Grifola umbellata

Grifola umbellata (Fries) is a traditional Chinese medicinal mushroom. In this paper, the effects of cultural condition on the mycelial growth and exopolysaccharide (EPS) production were studied. Glucose was the best carbon source for mycelia growth and EPS production. Yeast extract was the best nitrogen source for mycelia growth, whereas skim milk as nitrogen source can remarkably improve EPS production. The optimal medium constituents for EPS production were as follows: glucose 3%, skim milk 0.2%, 0.1% KH₂PO₄, 0.1% MgSO₄, 7H₂O and 0.005% vitamin B1. The initial pH value of 5 was the most efficient to EPS production. The G. umbellata culture with skim milk as nitrogen source displayed a much higher specific EPS yield of 112.35 mg/g, accounting for a 4.36 times increase compared to that with combined nitrogen source medium.     

Calcite Flotation in Potassium Oleate/Potassium Dihydrogen Phosphate System

Calcite flotation in acidic media is a difficult task due to the solubility of calcite and consequently the release of calcium ions in the flotation pulp. In addition, the interaction of calcium ions with the flotation reagents requires the correct selection of these reagents. In this study, potassium oleate and potassium dihydrogen phosphate (KH₂PO₄) were used as collector and depressant, respectively. Micro‐flotation experiments were conducted to probe the effect of these chemical reagents as well as their interaction on calcite flotation using H₂SO₄ as a pH regulator. In addition, to elucidate the depressing action of KH₂PO₄ on calcite, electrokinetic properties of calcite have been measured in relation to pH and in the absence and presence of KH₂PO₄. Moreover, thermodynamic calculations were used to rationalize the reasons for calcite depression as well as the adsorption mechanism of KH₂PO₄ onto the calcite surface.     

Screening of <Emphasis Type="Italic">Candida utilis</Emphasis> and medium optimization for co-production of <Emphasis Type="Italic">S</Emphasis>-adenosylmethionine and glutathione

An effective S-adenosylmethionine and glutathione enriching yeast mutant of Candida utilis CCTCC M 209298 was first screened from plates containing 0.5 g/L of DL-ethionine by complex mutagenesis with UV and γ-ray in this study. Medium components optimization for enhanced co-production of S-adenosylmethionine and glutathione by C. utilis CCTCC M 209298 was further carried out using response surface methodology. The significant factors influencing S-adenosylmethionine and glutathione co-production were selected by Plackett-Burman design as sucrose, KH₂PO₄ and L-methionine, and Box-Behnken design was applied for further optimization studies. Based on these approaches, the optimized concentrations on medium components for higher co-production of S-adenosylmethionine and glutathione were sucrose 35.4 g/L, (NH₄)₂SO₄ 10 g/L, KH₂PO₄ 12.3 g/L, MgSO₄·7H₂O, 0.05 g/L, CaCl₂ 0.05 g/L and L-methionine 4.6 g/L. The medium optimization by response surface methodology led to a total production of 589.3 mg/L on S-adenosylmethionine and glutathione, which was 2.4-fold increased compared with the medium without optimization.     

Medium Optimization for Exopolysaccharide Production in Liquid Culture of Endophytic Fungus Berkleasmium sp. Dzf12

Berkleasmium sp. Dzf12, an endophytic fungus from Dioscorea zingiberensis, is a high producer of spirobisnaphthalenes with various bioactivities. The exopolysaccharide (EPS) produced by this fungus also shows excellent antioxidant activity. In this study, the experimental designs based on statistics were employed to evaluate and optimize the medium for EPS production in liquid culture of Berkleasmium sp. Dzf12. For increasing EPS yield, the concentrations of glucose, peptone, KH₂PO₄, MgSO₄·7H₂O and FeSO₄·7H₂O in medium were optimized using response surface methodology (RSM). Both the fractional factorial design (FFD) and central composite design (CCD) were applied to optimize the main factors which significantly affected EPS production. The concentrations of glucose, peptone and MgSO₄·7H₂O were found to be the main effective factors for EPS production by FFD experimental analysis. Based on the further CCD optimization and RSM analysis, a quadratic polynomial regression equation was derived from the EPS yield and three variables. Statistical analysis showed the polynomial regression model was in good agreement with the experimental results with the determination coefficient (adj-R²) as 0.9434. By solving the quadratic regression equation, the optimal concentrations of glucose, peptone and MgSO₄·7H₂O for EPS production were determined as 63.80, 20.76 and 2.74 g/L, respectively. Under the optimum conditions, the predicted EPS yield reached the maximum (13.22 g/L). Verification experiment confirmed the validity with the actual EPS yield as 13.97 g/L, which was 6.29-fold in comparison with that (2.22 g/L) in the original basal medium. The results provide the support data for EPS production in large scale and also speed up the application of Berkleasmium sp. Dzf12.     

Response of wheat (Triticum aestivum) and pearl-millet (Pennistum americanum) to zinc fertilizers on two soils

Responses of ZnSO₄, Zn₃ (PO₄)₂ · 4H₂O, ZnO, ZnNH₄PO₃ · 2H₂O and zincated superphosphate were studied on wheat (Triticum aestivum) and pearl-millet (Pennistem americanum) in Balsamand sand (Ustipsament) and Ladwa fine loam (Typic Camborthids). In Balsamand sand all Zn fertilizers increased wheat and pearl-milllet grain yield significantly over control but ZnNH₄ PO₄ · 2H₂O and zincated super were the best sources. Straw yield was also highest due to zincated super and ZnNH₄PO₄ · 2H₂O applications. Zinc sulphate was significantly inferior to zincated super and ZnNH₄PO₄ · 2H₂O. In Ladwa fine loam, all fertilizers gave significantly higher grain yield of wheat and pearl-millet than control except ZnO in pearl-millet. Highest yield in this soil was obtained by ZnSO₄ · 7H₂O followed by ZnNH₄ PO₄ · 2H₂O and then zincated super.In Balsamand sand, the Zn fertilizers significantly increased the Zn concentration and Zn uptake of wheat grain. In pearl-millet, only Zn uptake was increased significantly with Zn fertilizers. Zincated super gave highest Zn uptake.The concentration of P in wheat grain was increased by Zn fertilizers in Balsamand sand, and also in pearl-millet where zincated super and ZnNH₄PO₄ were most effective in increasing the P content.When Zn fertilizers were applied to preceding pearl-millet the effect on succeeding wheat crop were in the same order as direct application of Zn fertilizers. Zincated super was the best and ZnO worst with respect to wheat grain and straw yield and uptake of Zn and P.     

Curing Behavior and Structure of Magnesium Phosphate Chemically Bonded Ceramics with Different MgO to KH2PO4 Ratios

Magnesium phosphate chemically bonded ceramics attracted much attention because of its good biocompatibility. In this work, curing behavior and microstructure of magnesium phosphate chemically bonded ceramics with different MgO to KH₂PO₄ ratios were investigated. The results showed that the setting time decreased and the maximum temperature during the solidifying process increased as the increase of MgO to KH₂PO₄ ratio. Phase compositions were different for those samples fabricated with different MgO to KH₂PO₄ ratios. KH₂PO₄, MgO, and hydrated product existed in the sample with lower MgO to KH₂PO₄ ratio because of the incomplete reaction, and numerous acicular polycrystals were found. There were only MgO and hydrated product existed with the higher MgO to KH₂PO₄ ratio. Besides, a gelatinous structure with lots of cracks was also found. Clearly, the properties of magnesium potassium phosphate chemically bonded ceramics could be controlled by changing the MgO to KH₂PO₄ ratio. It is better to fabricate magnesium phosphate chemically bonded ceramics with optimal structure and properties suitable for biomedical applications in range of MgO to KH₂PO₄ ratio from 3:1 to 4:1 in this preparating conditions.     

New Environmentally Friendly Oxidative Scission of Oleic Acid into Azelaic Acid and Pelargonic Acid

Oleic acid (OA) is a renewable monounsaturated fatty acid obtained from high oleic sunflower oil. This work was focused on the oxidative scission of OA, which yields a mono-acid (pelargonic acid, PA) and a di-acid (azelaic acid, AA) through an emulsifying system. The conventional method for producing AA and PA consists of the ozonolysis of oleic acid, a process which presents numerous drawbacks. Therefore, we proposed to study a new alternative process using a green oxidant and a solvent-free system. OA was oxidized in a batch reactor with a biphasic organic-aqueous system consisting of hydrogen peroxide (H₂O₂, 30 %) as an oxidant and a peroxo–tungsten complex Q₃{PO₄[WO(O₂)₂]₄} as a phase-transfer catalyst/co-oxidant. Several phase-transfer catalysts were prepared in situ from tungstophosphoric acid, H₂O₂ and different quaternary ammonium salts (Q⁺, Cl^–). The catalyst [C₅H₅N(n-C₁₆H₃₃)]₃{PO₄[WO(O₂)₂]₄} was found to give the best results and was chosen for the optimization of the other parameters of the process. This optimization led to a complete conversion of OA into AA and PA with high yields (>80 %) using the system OA/H₂O₂/[C₅H₅N(n-C₁₆H₃₃)]₃{PO₄[WO(O₂)₂]₄} (1/5/0.02 molar ratio) at 85 °C for 5 h. In addition, a new treatment was developed in order to recover the catalyst.     

Self-assembly synthesis of dumbbell-like MnPO4·H2O hierarchical particle and its application in LiMnPO4/C cathode materials

The large-scale and efficient synthesis of MnPO₄·H₂O is an urgent problem to be solved. In this paper, self-assembled dumbbell-shaped MnPO₄·H₂O particles were successfully synthesized just using KMnO₄ and commercial concentrated H₃PO₄, and then employed as the precursor to prepare LiMnPO₄/C composites. The XRD, SEM, TEM, and electrochemical performance tests were used to investigate MnPO₄·H₂O and the corresponding LiMnPO₄/C. The formation mechanism of MnPO₄·H₂O was discussed. The results showed that temperature and water content have a significant effect on the yield, purity, and morphology of MnPO₄·H₂O. The synthesized LiMnPO₄/C with reduced carbon content at 650 °C delivered a discharge capacity of 109.3 mA h g^-1 at 1 C and 104.3 mA h g^-1 at 2 C. This green and efficient synthesis method of MnPO₄·H₂O provides a new idea for the large-scale preparation of LiMnPO₄/C cathode materials.     

Biodiesel Production from the Lipid of Wastewater Sludge Using an Acidic Heterogeneous Catalyst

The production of biodiesel from the lipid of wastewater sludge was studied using SBA‐15 impregnated with the heteropolyacid H₃PO₄·12WO₃·xH₂O (PW₁₂) as a mesoporous heterogeneous catalyst. X‐ray diffraction, Brunauer‐Emmett‐Teller surface area, thermalgravimetric analysis, and scanning electron microscopy were applied to characterize the prepared catalysts. Catalytic performances were evaluated in a microreactor setup under different experimental conditions. The biodiesel yield for a sample impregnated with 15 % PW₁₂ was 30.14 wt‐% at a temperature of 135 °C and a pressure of 135 psi for 3 h reaction time.     

Electrokinetic Properties of Vermiculite and Expanded Vermiculite: Effects of pH,Clay Concentration and Mono- and Multivalent Electrolytes

Abstract

In this study, the zeta potential values of vermiculite and expanded vermiculite were measured to determine the effect of pH, clay concentration, and various mono- and multivalent electrolytes including NaCl, KCl, NH₄Cl, NaNO₃, NaClO₄, Na₂SO₄, Na₂CO₃, Na₃PO₄·12H₂O, MgCl₂·6H₂O, CaCl₂·2H₂O, BaCl₂, SrCl₂·6H₂O, CuCl₂·2H₂O, CoCl₂·6H₂O, NiCl₂, AlCl₃, and CrCl₃·6H₂O on the electrokinetic properties of vermiculite samples. It was found that generally the measured zeta potential values of expanded vermiculite for the studied systems were slightly more negative than that of vermiculite. The pH profiles of vermiculite and expanded vermiculite at acidic, natural, and basic pH values were obtained to determine the effect of time on the pH values of clay suspensions. The zeta potential measurements showed that the surface charge of clay particles was negative in water. The isoelectric point of vermiculite and expanded vermiculite were determined as pH 2.30 and 2.57, respectively. Divalent cations (Mg²⁺, Ca²⁺, Sr²⁺, and Ba²⁺), heavy metal ions (Cu²⁺, Ni²⁺, and Co²⁺) and trivalent cations (Al³⁺ and Cr³⁺) were potential determining ions for vermiculite and expanded vermiculite particles. Moreover, divalent and trivalent cations caused the change of surface charge from negative to positive. On the other hand, monovalent cations (Na⁺, K⁺ and NH₄ ⁺), monovalent anions (Cl^?, NO₃ ^?, and ClO₄ ^?) and multivalent anions (SO₄ ^2?, CO₃ ^2?, and PO₄ ^3?) acted as indifferent ions for these clay particles.     

New open-framework beryllium phosphates with hcb,sql, and bnn topologies

Three new beryllium phosphates, namely, H₃aep·Be₂(PO₄)₂(H₂PO₄)·H₂O (1), H₂tmdp·Be₃(HPO₄)₃(PO₄CH₃)·2.25H₂O (2), and H₂dmpda·Be₃(PO₄)(HPO₄)₂(H₂PO₄) (3), were prepared under solvothermal conditions. These compounds display different open-framework structures with hcb (for 1), sql (for 2), and bnn (for 3) topologies, respectively. The formation of phosphate ester from in situ esterification reaction of phosphoric acid and methanol is noteworthy.