Screening of supports for the immobilization of pectinmethylesterase from acerola (Malpighia glabra L)

A partially purified extract of pectinmethylesterase (PME) from acerola fruit was immobilized on various supports: glass, celite, chrysotile, agarose, concanavalin A Sepharose 4B, egg shell, polyacrylamide and gelatin. In addition, reticulation with glutaraldehyde was assessed, as well as the use of gelatin in the presence of celite, glass and silica. The highest immobilization yields were obtained when the pectinmethylesterase was immobilized in concanavalin A Sepharose 4B (81.7%) and in gelatin‐water (78.0%). Copyright © 2004 Society of Chemical Industry     

Production of alkyl esters from tallow and grease using lipase immobilized in a phyllosilicate sol-gel

The lipase-catalyzed synthesis of alkyl esters from tallow and grease using Pseudomonas cepacia lipase (PS-30) immobilized within a phyllosilicate sol-gel matrix was investigated. The effects of the presence of alcohol and of the amount of enzyme used were studied. The matrix-immobilized PS-30 lipase effectively converted grease and tallow to ethyl esters in greater than 95% yield when using ethanol. The final conversion of grease or tallow to alkyl esters was aided by the addition of molecular sieves (0.4 wt% of substrates) to the reaction mixture. The matrix-immobilized PS-30 enzyme was easily recovered and could be reused at least five times without losing its activity. Accordingly, the phyllosilicate sol-gel immobilized PS-30 lipase is potentially useful for the economic production of biodiesel fuel.     

Phenolics extraction from Agave americana (L.) leaves using high-temperature, high-pressure reactor

The Agave americana plant has been largely used in traditional medicine. The setting up of efficient methods for phenolics extraction from A. americana leaves is one of great interest. With the aim of optimizing phenolics extraction from this material, the effects of temperature (from 25 to 150 °C) and extraction time (from 15 to 240 min) were investigated using a high-temperature, high-pressure (PARR) reactor, under either air or nitrogen atmosphere. Total polyphenols and flavonoids were determined, and their antioxidant activity was measured by the DPPH radical method. The use of PARR reactor for phenolics extraction proved to be more efficient compared to the conventional solid-liquid extraction at room temperature. The results of this work demonstrated that an increase in both temperature and extraction time led to a corresponding increase in the amount of phenolic compounds extracted and suggested that, after process optimization, this material could be used as an interesting alternative source of polyphenols.     

Production of lactic acid from beet molasses by calcium alginate immobilized Lactobacillus delbrueckii IFO 3202

Lactic acid was produced from pretreated beet molasses by the homofermentative organism Lactobacillus delbrueckii subsp delbrueckii IFO 3202 entrapped in calcium alginate gel using batch, repeated batch and continuous fermentation systems. In batch fermentation studies successful results were obtained with 2.0–2.4 mm diameter beads prepared from 2% sodium alginate solution. The highest effective yield (82.0%) and conversion yield (90.0%) were obtained from substrate concentrations of 52.1 and 78.2 g dm⁻³ respectively. The gel beads produced lactic acid for 14 consecutive batch fermentations without marked activity loss and deformation. In the continuous fermentation, the highest lactic acid (4.22%) was obtained at a dilution rate of 0.1 h⁻¹ while the highest productivity (13.92 g dm⁻³ h⁻¹) was obtained at a dilution rate of 0.4 h⁻¹. © 1999 Society of Chemical Industry     

Biosorption of cadmium(II) and lead(II) from aqueous solutions using Pleurotus ostreatus immobilized on bentonite

The purpose of this work was to evaluate the potential of a white rot fungi (P. ostreatus) immobilized on bentonite, in a continuous flow removal of trace heavy metals. The procedure is based on the biosorption of Cd(II) and Pb(II) ions on a column of bentonite loaded with dried, dead fungi components prior to their determination by atomic absorption spectroscopy (AAS). Cd(II) and Pb(II) were determined with a relative error of less than 5%. Various parameters such as “pH, amount of adsorbent, eluent type and volume, flow rate of the solution and matrix interference effect” on the retention of the metal ions were investigated. This procedure was applied to Cd(II) and Pb(II) determination in aqueous solutions, including tap water system. The optimum experimental parameters were determined to be pH 5, concentration of 10 mg/L, contact time of 30 min and 0.2 g of adsorbent for a quantitative adsorption of the metals. The optimum flow rate was found to be 2.5 mL/min for all metal ions. Each column can be used up to 20 successive analyses without considerable change in recoveries of metal ions.

The proposed method is excellent as regards simplicity, sensitivity, selectivity, precision, accuracy and column stability.     

Continuous biobleaching of black liquor from the pulp and paper industry using an immobilized cell system

Three different support materials have been screened for immobilization of Phanerochaete chrysosporium for biobleaching of anaerobically digested black liquor. Of these, jute rope-immobilized P. chrysosporium showed better performance than cotton and wheat carriers in terms of decolorization and COD reduction. Process parameters such as temperature, mycelial load, pH, glucose concentration and retention time were optimized using jute-immobilized fungus and the optimal values recorded were 40°C, 340 mg, 5·5, 1% (w/v) and 72 h, respectively. Continuous biobleaching of anaerobically digested black liquor using a packed bed reactor system carrying the jute-immobilized fungal biomass was successfully carried out over a period of 21 days. © 1998 Society of Chemical Industry     

Characterization of tributyrin hydrolysis by immobilized lipase on woolen cloth using conventional batch and novel spinning cloth disc reactors

Optimal loading and operating conditions for a new, superior immobilization of amano lipase from Pseudomonas fluorescens on woolen cloth were determined. The optimal enzyme loading was 46.8 mg g dry cloth⁻¹ with activity of 200 U. A batch reactor was used to characterize process conditions important to industrial application of the wool immobilized lipase. The optimal pH for immobilized lipase in tributyrin hydrolysis was 7, slightly lower than that of free lipase (pH 8). The optimal temperature for both free and immobilized lipase was 45 °C. The immobilized lipase was more stable to reuse than some other lipase immobilizations, maintaining 85% of its activity after 6 long term runs and 75.8% of the original activity after storage of 40 weeks at 4 °C. The thermal stability of lipase was improved by 2.4 times after immobilization. The thermal deactivation rate of immobilized lipase followed the Arrhenius law with E_d = 199 kJ mol⁻¹. The Michaelis–Menten constant (K_m) of the lipase increased from 1.63 mM to 4.48 mM after immobilization. The immobilized lipase was also successfully applied for tributyrin hydrolysis in a novel enzyme process intensification technology – the spinning cloth disc reactor (SCDR): conversion increased by around 13% under similar conditions compared to a conventional batch stirred tank reactor. The SCDR is therefore key to exploiting the advantages of the wool immobilized lipase developed in this work.     

Hydrolysis of milk lactose in a packed bed reactor system using immobilized yeast cells

BACKGROUND: Hydrolysis of lactose with β‐D‐galactosidase is one of the most promising biotechnological applications in the food industry because of its use in the production of low lactose milk products and whey hydrolysis. To overcome the problem of enzyme extraction from cells due to the intracellular nature of β‐D‐galactosidase and the poor permeability of the cell membrane to lactose, permeabilization of yeast cells was investigated. Permeabilized whole cells have been claimed to have an advantage over more pure enzyme preparations. In view of the advantages of immobilized cell systems over free cell systems, permeabilized cells were immobilized by an entrapment method in calcium alginate gel. A packed bed reactor together with this immobilized cell system has been used for hydrolysis of milk lactose in a continuous system. RESULTS: Different process parameters (temperature, substrate feed rate, biomass load and time‐course) were optimized to maximize lactose hydrolysis. The immobilized yeast cells (300 mg dry wt) resulted in 87.2% hydrolysis of milk lactose at 30 °C and flow rate 7 mL h^?1 in a packed bed reactor system. CONCLUSION: This convenient and relatively inexpensive method of immobilization, resulting in high hydrolysis potential in a continuous system, indicates that permeabilized yeast cells have the potential for the production of low lactose milk and milk products. Copyright © 2010 Society of Chemical Industry     

大孔树脂分离纯化沙芥黄酮的工艺研究

用大孔吸附树脂分离纯化沙芥总黄酮,比较了7种大孔树脂对沙芥总黄酮的静态吸附动力学特性,优选出D-4020型大孔吸附树脂分离纯化沙芥总黄酮,并对其进行动态吸附实验。结果表明,D-4020纯化沙芥总黄酮的最佳工艺参数为:上样液浓度0.4 mg/mL,pH值5,上样流速2 mL/min;使用4BV用量95%的乙醇作为洗脱剂,洗脱流速为2 mL/min。采用该工艺分离纯化沙芥总黄酮含量达40.91%。     

硅胶固载Ru(Ⅱ)Cl2(PPh3)3催化苯乙酮不对称加氢

通过共价键联的方法将RuCl_2(PPh_3)_3配合物固载于手性二胺修饰的硅胶表面,制备了多相不对称加氢催化剂。采用等离子体发射光谱(ICP)、红外光谱(FTIR)和紫外光谱(UV—Vis)等手段对制备的催化剂进行了表征。结果表明,RuCl_2(PPh_3)_3配合物固载于硅胶表面保持了原有的结构性能。在苯乙酮不对称加氢反应中,不同手性二胺对催化反应具有明显的影响,(1S,2S)-1,2-二苯基乙二胺的手性诱导能力强于其他二胺,优化条件下,苯乙酮转化率达100%,(R)-苯乙醇的对映体过量值达50%,固体催化剂具有良好的稳定性和重复使用性。     

Production of mustard protein isolates from oriental mustard seed (Brassica juncea L.)

A membrane-based process to produce protein isolates from seeds of oriental mustard (Brassica juncea) was developed by modifying a method originally developed for rapeseed. The optimized process consisted of extraction at pH 11, ultrafiltration with concentration factor 4, diafiltration with diavolume 3, and precipitation at pH 5. The process, based on defatted oriental mustard seed containing 45–50% protein, recovered 81% of the protein in useful products: 47.3% in precipitated protein isolate (PPI), 3.8% in soluble protein isolate (SPI), and 13% in meal residue. Mass yields were 21.9% in PPI, 2.8% in SPI, and 38.4% in meal residue. The losses in the system included ∼10% loss of nonprotein nitrogen, and <9% into permeate and transfer losses. The PPI compared favorably with soy protein isolate in typical meat products in terms of color, texture, and flavor. The work confirms that oriental mustard is a potentially useful source of edible protein.     

Comparison of prednisolone production from cortexolone by free and immobilized isolated and standard collection strains using mixed culture techniques

The bioconversion of cortexolone (Reichstein's Compound S) to hydrocortisone or hydrocortisone to prednisolone by reference and isolated fungi and bacteria were investigated. The reference strains Cunninghamella echinulata ATCC 8688a and Bacillus sphaericus ATCC 13805, and the isolates C echinulata SRP III and B sphaericus SRP III were used as free or immobilized forms in single or mixed cultures by either sequential or concomitant mixing. In single cultures, immobilized fungi C echinulata ATCC 8688a and C echinulata SRP III showed less hydrocortisone yield than the free form, whereas immobilized B sphaericus ATCC 13805 and B sphaericus SRP III gave higher prednisolone yield than the free form. In mixed cultures, free fungi with immobilized bacteria of both isolated and standard strains showed the highest prednisolone yield both by concomitant and sequential mixing. The highest prednisolone yield of 72.5±0.78% with a bioconversion rate of 0.76% h ⁻¹ by sequential mixing was obtained with free C echinulata ATCC 8688a with immobilized B sphaericus ATCC 13805 at 96 h, whereas the free C echinulata SRP III with immobilized B sphaericus ATCC 13805 and the free C echinulata SRP III with immobilized B sphaericus SRP III gave 63.4±0.74% and 47.7±0.44% at 120 h with bioconversion rates of 0.53 and 0.40% h⁻¹ respectively. Free C echinulata SRP III with immobilized B sphaericus SRP III gave a maximum yield of 52.8±0.82% with a bioconversion rate of 0.44% h ⁻¹ at 120 h which was comparable to 59.2±0.44% with a bioconversion rate of 0.49% h ⁻¹ obtained by free C echinulata ATCC 8688a with immobilized B sphaericus ATCC 13805 using concomitant mixing. This study indicated high biotransformation activity of free fungal and immobilized bacterial isolates which showed comparable steroidal productivity to the standard strains both in single and mixed cultures by the concomitant mixing technique. © 1999 Society of Chemical Industry     

Optimization of oil extraction from Pitanga (Eugenia uniflora L.) leaves using simplex centroid design

Simplex centroid design (SCD) was employed to optimize the mixing of petroleum ether, n-hexane, methanol and ethanol for the extraction of oil (PLO) from Pitanga (Eugenia uniflora L.) leaves, via Soxhlet extraction. The highest yield (54%) of Pitanga leaf oil (PLO) was obtained with 100% ethanol and the lowest yield (16%) from the mixture of methanol (33.3%)/hexane (33.3%)/ethanol (33.3%). The coefficient of determination (R²) of the model equation obtained was 0.91, while the adjusted R² and predicted R² were 0.8729 and 0.951, respectively. The saponification value (S.V.), iodine value, acid value and free fatty acid (FFA) are 35.34 mgKOH/g, 72.97 mgI₂/g oil, 32.41 and 16.30 mgKOH/g, respectively.     

Superabsorbent polymer prepared using carboxymethyl cellulose derived from Ceiba pentandra (L.) Gaertn. (kapok) cotton

Superabsorbent polymers (SAPs) were synthesized by grafting acrylic acid and butyl acrylate onto carboxymethyl cellulose (CMC) modified from Ceiba pentandra (L.) Gaertn. (kapok) cotton, with N,N′‐methylenebisacrylamide as a crosslinker and ammonium persulphate as initiator. The effect of distilled water, saline solution, and applied pressure on superabsorbent was investigated. The product exhibited the maximum water absorbency of 554 g/g in distilled water and 96 g/g in saline solution. The SAP achieved the highest water absorbency under load of 83 g/g under applied pressure of 7.6 g/cm². The kapok cotton modified cellulose‐based SAP exhibited stronger gel strength than the SAP based on commercial CMC. This is probably due to the higher grafting efficiency (78.3%) of the former. The SAP was characterized by FTIR analysis, thermogravimetric analysis, and scanning electron microscopy. Thermogravimetric analysis results showed that the SAP, with AA and BA grafted onto CMC, had better thermal stability than CMC alone. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40808.     

Evaluation of lipase from Burkholderia cepacia immobilized in alginate beads and application in the synthesis of banana flavor (isoamyl acetate)

The alginate in bead forms was used to immobilize Burkholderia cepacia lipase. The microencapsulation technique for lipase entrapment was a 2% (w/v) of sodium alginate concentration prepared by ionic gelation using calcium chloride as the cross-linking agent in a gelling solution. The beads were tested in different solvents as acetone, chloroform, toluene, n-hexane, and n-heptane. Over a 5-day period (120?h), the n-heptane maintained the reasonable (excellent) residual activity of the immobilized lipase. Morphological studies on reused beads and new beads were performed. All beads for isoamyl acetate yield were tested. The reused bead leaches substantially, with a maximum ester yield of 92%. With modifications in the molar ratios, the synthesis of banana flavor (isoamyl acetate) was performed in both the alcohol per acid and acid per alcohol excesses.     

Immobilization of a cyclodextrin glucanotransferase (CGTase) onto polyethylene film with a carboxylic acid group and production of cyclodextrins from corn starch using CGTase‐immobilized PE film

Carboxylic acid groups were introduced onto polyethylene (PE) film by radiation‐induced graft copolymerization. Subsequently, the clodextrin glucanotransferase (CGTase) was immobilized on the PE film with a carboxylic acid group. The activity of the immobilized CGTase on PE film was in the range of 0.40–1.04 U/cm² per min. The production of cyclodextrins (CDs) from corn starch was examined using the CGTase‐immobilized PE film. The production ratios of CDs using CGTase‐immobilized PE film was in the following order: α–CD > β–CD > γ–CD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2451–2457, 2002     

Comparative analysis of phytosterol components from rapeseed (Brassica napus L.) and olive (Olea europaea L.) varieties

Phytosterols occur in relatively high concentration in the seeds of rapeseed (Brassica napus L.) and in lower concentration in olive (Olea europaea L.) oil. The aim of this research was to investigate some new rapeseed varieties and olive genotypes that are grown in Northwest Turkey and to compare the phytosterol contents of both crops. For rapeseed, the data were collected in the growing seasons 2004–2005 from a field experiment with 19 new rapeseed varieties and three replications. For olives, 21 different varieties were used in the 2004–2005 and 2005–2006 growing seasons. The separation and identification of free phytosterols and the analysis of their contents were successfully achieved using the capillary column‐gas chromatographic method. According to the obtained results, for rapeseed, sitosterol (1.54–2.36 g/kg) was the major component of total phytosterols, followed by campesterol (0.02–1.58 g/kg) and brassicasterol (0.26–0.58 g/kg). Regarding the olive varieties, the sitosterol content changed between 1.03 and 2.01 g/kg, followed by avenasterol ranging from 0.07 to 0.44 g/kg. The brassicasterol, campesterol and stigmasterol contents did not affect the total amount of sterols. The total phytosterol content ranged between 4.25 and 11.37 g/kg for rapeseed and 1.29 and 2.38 g/kg for olives.