微生物利用废弃物产生絮凝剂的研究与应用

作者介绍了微生物利用废弃物如麦芽根、水产排水等产生絮凝剂的研究与应用.同时还介绍了一种以微生物利用水产排水产生的絮凝剂处理该水产排水,所得沉淀物用作饲料成分的方法.     

Crystallization of alkaline protease as a means of purification process

A purification protocol of alkaline protease purification using crystallization was developed by investigating the effects of pH, temperature, initial enzyme concentration, salt (as crystal inducer) concentration, and the presence of impurity proteins. A commercial alkaline protease solution was used as a starting material and NaCl was used as a crystal inducing salt. The crude enzyme solution was first diafiltered against deionized water and then concentrated by ultrafiltration. To the enzyme concentrate appropriate amount of NaCl was added to induce the crystallization which was lasted for 24 hours, and the enzyme crystals formed were filtered and washed with deionized water before being resolubilized. Crystal habit was typical needle shape, and the reaction order of its formation was estimated to be 1.53. The crystallization was strongly influenced by initial enzyme concentration. Solubility of alkaline protease at 25°C was 24.8 mg/ml, which was about one half of that of 4°C. Enzyme recovery yield of the purification process including the crystallization step ranged 50 to 60 %. The crystallization step was shown to successfully exclude impurity proteins from their habits as evidenced by gel permeation chromatography. The optimum condition for the crystallization was: pH 9.0, 25°C temperature, ca. 53 mg/ml or higher enzyme concentration, and minimum 5 % (w/w) NaCl concentration. In summary, an enzyme purification protocol based on crystallization was established, which can be applied to obtain a higher-purity alkaline protease solution on a large scale.     

Extraction of phenolic compounds and anthocyanins from blueberry (Vaccinium myrtillus L.) residues using supercritical CO2 and pressurized liquids

This work explored the potential of subcritical liquids and supercritical carbon dioxide (CO₂) in the recovery of extracts containing phenolic compounds, antioxidants and anthocyanins from residues of blueberry (Vaccinium myrtillus L.) processing. Supercritical CO₂ and pressurized liquids are alternatives to the use of toxic organic solvents or extraction methods that apply high temperatures. Blueberry is the fruit with the highest antioxidant and polyphenol content, which is present in both peel and pulp. In the extraction with pressurized liquids (PLE), water, ethanol and acetone were used at different proportions, with temperature, pressure and solvent flow rate kept constant at 40 °C, 20 MPa and 10 ml/min, respectively. The extracts were analyzed and the highest antioxidant activities and phenolic contents were found in the extracts obtained with pure ethanol and ethanol + water. The highest concentrations of anthocyanins were recovered with acidified water as solvent. In supercritical fluid extraction (SFE) with CO₂, water, acidified water, and ethanol were used as modifiers, and the best condition for all functional components evaluated was SFE with 90% CO₂, 5% water, and 5% ethanol. Sixteen anthocyanins were identified and quantified by ultra performance liquid chromatography (UPLC).     

羧甲基琼脂糖微球的制备及其在国产碱性蛋白酶纯化中的应用

以琼脂糖粉末为原料,利用反相悬浮原理制备琼脂糖凝胶微球。所得琼脂糖微球的粒径分布在45～165μm范围内,并对其进行了交联。以自制交联琼脂糖微球为基质,对其进行了羧甲基化反应。依据离子交换容量进行键合量的表征,综合考察了各种反应试剂的用量、反应温度、反应时间等条件对键合量的影响。将所得的羧甲基键合微球用于碱性蛋白酶粗品的分离纯化,结果表明,自制羧甲基弱阳离子交换填料对国产碱性蛋白酶具有较好的分离纯化、除色以及除味等作用,可以达到国外同类产品的效果。     

Extraction of native collagen from limed bovine split wastes through improved pretreatment methods

BACKGROUND: The large amount of limed bovine split wastes discharged by the leather industry has raised concerns regarding their environmental effect. The objective of this work was to perform pilot plant trials to extract high‐value native collagen from these wastes through improved pretreatment methods. RESULTS: EDTA‐ and HCl‐pretreatment gave similar removal percentages of inorganic substances. Owing to the open structure of fibers, the collagen yield of HCl‐pretreated splits (HPS) (41.31%) was higher than that of EDTA‐pretreated splits (EPS) (10.42%). Furthermore, HCl‐pretreated split collagen (HPC) had a more acidic isoelectric point, lower content of primary amino groups, larger Z‐average particle size and higher relative viscosity than EDTA‐pretreated split collagen (EPC). Electrophoretic analysis and circular dichroism spectra revealed the maintenance of polypeptide and triple helix conformation, respectively. In addition, the transition temperatures of EPC (34.7 °C) and HPC (34.6 °C) detected by differential scanning calorimetry (DSC) were close to that of commercial collagen from calfskin (CCC) (35.7 °C). CONCLUSION: A process of native collagen extraction from limed bovine split wastes was proposed. While both EPC and HPC represented similar physicochemical properties to those of CCC, the collagen yield of HPS was much higher than that of EPS. Copyright © 2008 Society of Chemical Industry     

Synthesis of magnesium sulfate from seawater using alkaline industrial wastes,sulfuric acid,and organic solvents

ABSTRACT

In this study, we used three processes to synthesize magnesium sulfate from seawater. First, alkaline industrial wastes, cement kiln dust and paper sludge ash, were injected to the seawater to precipitate magnesium in the form of magnesium hydroxide (Mg(OH)₂). Then, magnesium was eluted with a small amount of H₂SO₄ to make a high concentration magnesium solution. Finally, an organic solvent was added to precipitate magnesium sulfate (MgSO₄). Over 90% of magnesium was recovered through the three processes. It is expected that 11.3 kg of magnesium sulfate (based on MgSO₄ · 6H₂O) can be synthesized from 1 ton of seawater.     

工农业废弃物资源化用于除氟研究进展

吸附法是水溶液除氟应用最广泛的方法,将工农业废弃物作为除氟吸附剂可减少废弃物对环境的污染,降低除氟成本.作者基于对国内外砖粉、红泥、粉煤灰等工业废弃物及竹炭、稻草、果皮等农业废弃物及其制品用于水溶液除氟研究现状.提出废弃物制吸附剂除氟的后续研究应侧重预处理和使用后的处置方法.以及工业化应用理论基础研究,以寻求经济、高效的治理工艺,早日大规模应用于水处理中.     

Extraction of caffeine from tea stalk and fiber wastes using supercritical carbon dioxide

The purpose of this study was to investigate obtaining of caffeine from tea plant wastes by supercritical carbon dioxide extraction. Experiments were carried out with tea stalk and fiber wastes of Turkish tea plants that has no economical value. Stalk and fiber wastes were supplied from tea factories. These wastes were ground, sieved and dried at 105 °C temperature in an oven. Parameters affecting caffeine leaching from tea wastes were determined to be, extraction time, extraction temperature, carbon dioxide flow rate, process pressure and particle size. The maximum yield of caffeine from tea stalk wastes and fiber wastes were 14.9 mg/g tea stalk and 19.2 mg/g tea fiber, respectively. The yield increase had been recorded as 61.9% and 65.5%, respectively, in comparison with the chloroform extraction of tea stalk and fiber wastes.     

Extraction of caffeine from tea stalk and fiber wastes using supercritical carbon dioxide

The purpose of this study was to investigate obtaining of caffeine from tea plant wastes by supercritical carbon dioxide extraction. Experiments were carried out with tea stalk and fiber wastes of Turkish tea plants that has no economical value. Stalk and fiber wastes were supplied from tea factories. These wastes were ground, sieved and dried at 105 °C temperature in an oven. Parameters affecting caffeine leaching from tea wastes were determined to be, extraction time, extraction temperature, carbon dioxide flow rate, process pressure and particle size. The maximum yield of caffeine from tea stalk wastes and fiber wastes were 14.9 mg/g tea stalk and 19.2 mg/g tea fiber, respectively. The yield increase had been recorded as 61.9% and 65.5%, respectively, in comparison with the chloroform extraction of tea stalk and fiber wastes.     

Liquid-liquid extraction of protease from cold-adapted yeast Rhodotorula mucilaginosa L7 using biocompatible and biodegradable aqueous two-phase systems

This work aimed to optimize the extraction of an extracellular protease produced by the cold-adapted yeast Rhodotorula mucilaginosa L7 using aqueous two-phase systems (ATPS) comprising polyethylene glycol (PEG) and sodium citrate or sodium tartrate. First, the biocompatibility of the phase forming agents was assessed. The results obtained with PEG-2000, PEG-4000, and PEG-6000 demonstrated that even at large PEG concentrations (32 wt%) the protease maintains its activity after 3 h of reaction, whereas an increase in salt concentration provokes a gradual decrease in protease stability. Subsequently, the partitioning of the protease in both types of ATPS was assessed, evaluating the effect of temperature, molecular weight, and concentration of PEG on protease purification, using two 2³-full factorial designs. The best partitioning conditions were obtained in PEG-6000/sodium tartrate-based ATPS, at 30ºC (with a yield of 81.09 ± 0.66% and a purification factor of 2.51 ± 0.03). Thus, considering the biodegradable characteristics of the system, the PEG/sodium tartrate ATPS is a viable and economic low-resolution step in protease purification, with a strong potential for future industrial application.     

Production of thermostable alkaline lipase on vegetable oils from a thermophilic Bacillus sp. DH4, characterization and its potential applications as detergent additive

BACKGROUND: The alkaline lipase production on vegetable oils as sole carbon source, its characterization and effect of different commercial detergents and surfactants on enzymatic activity from thermophilic Bacillus sp. DH4 was investigated. RESULTS: The organism grew on mannose, but the amount of lipase secreted was significantly less than on vegetable oils. This study identified a simple substrate for lipase production and established the utility of groundnut oil for increasing the lipase yield. The enzyme was compatible with various ionic and non‐ionic surfactants as well as commercial detergents. Lipase activity was strongly inhibited by sodium dodecyl sulfate (SDS), but not by Triton X‐100 or Triton X‐114. The best assay conditions observed for this lipase was found to be pH 9.0 and 50 °C. The enzyme was stable at alkaline pH and considerable activity was observed at pH 10 and it retained 93% of the residual activity at 60 °C. The lipase showed a novel property of marked activation at alkaline pH. Wash performance analysis of commercial detergent for removal of fatty stains improved upon addition of lipase. CONCLUSION: The production on cheap vegetable oils, novel properties and resistance towards various surfactants and tolerance to commercial detergents make this lipase a potential additive for detergent formulations. Significance and impact of the study: Bacillus sp. produces alkaline and thermostable lipase on cheap vegetable oils and its compatibility can find use in the detergent industry. Copyright © 2008 Society of Chemical Industry     

3 300t/d熟料可焚烧工业废燃料烧成系统技术装备的开发设计

针对当前水泥行业发展趋势,结合日前参与的西班牙马拉加设计项目,介绍了3 300t/d熟料可焚烧工业废燃料烧成系统技术装备的开发设计以及烧成系统的配置情况。     

巨尾桉单宁的提取分离及其抗菌抗氧化性能

采用超声波辅助法提取了巨尾桉叶中的单宁,大孔树脂吸附法纯化了粗提物,考察了提取物对8种常见菌种的抑制作用和对H2O2、DPPH.和.OH的清除作用。结果表明,巨尾桉单宁的提取得率为4.01%;经树脂分离纯化后单宁质量分数达到53.12%;巨尾桉单宁对除大肠杆菌外的供试菌种均有较强的抑制作用,纯化后的单宁对金黄色葡萄球菌、酵母菌和痢疾杆菌的最低抑菌质量浓度(MIC)均为1.0 g/L,对蜡状芽孢杆菌和沙门氏菌的抑制作用优于阳性对照物;粗提物、纯化物在质量浓度为0.50 g/L时对H2O2有最大清除率,分别为80.00%、89.12%,其IC50分别为0.11、0.12 g/L;抗坏血酸、粗提物和纯化物均在质量浓度为1.50 g/L时对DPPH.有最大清除率,分别为98.43%、88.97%和92.21%。在清除.OH体系中,粗提物、纯化物均在质量浓度为4.00 g/L时有最大清除率,分别为87.52%和94.32%,各试样对.OH的清除能力依次为抗坏血酸>纯化物>粗提物。     

Purification and characterization of solvent‐tolerant,thermostable, alkaline metalloprotease from alkalophilic Pseudomonas aeruginosa MTCC 7926

BACKGROUND: Microbial proteases are becoming imperative for commercial applications. The protease secreted by Pseudomonas aeruginosa MTCC 7926, isolated from solvent‐contaminated habitat was purified and characterized for activity at various edaphic conditions. The purified alkaline protease was investigated for dehairing of animal skin, anti‐staphylococcal activity and processing of X‐ray film. RESULTS: The protease was 24‐fold purified by ammonium sulfate fractionation, sephadex G‐100 gel filtration and DEAE‐cellulose, with 36% recovery. K_M and V_max, using casein were 2.94 mg mL^?1 and 1.27 µmole min^?1, respectively. The apparent molecular mass by SDS‐PAGE was 35 kDa. Alkaline protease was active at pH 6–11 and temperature 25–65 °C. Its activity was (a) 86.8% in 100 mmol L^?1 NaCl, (b) >95% in metal ions (Mn²⁺, Ca²⁺, Mg²⁺, Fe²⁺) for 1 h, (c) >90% in bleaching agents and chemical surfactants, (d) 135.4 ± 2.0% and 119.9 ± 6.2% with rhamnolipid and cyclodextrin, respectively, (e) stable in solvents for 5–30 days at 27 °C, and (f) inhibited by EDTA, indicating metalloprotein. CONCLUSION: This work showed that purified protease retained its activity in surfactants, solvents, metals, and bleaching agents. The enzyme is an alternative for detergent formulations, dehairing of animal skin, X‐ray film processing, treatment of staphylococcal infections and possibly non‐aqueous enzymatic peptide synthesis. Copyright © 2009 Society of Chemical Industry     

Synthesis and characterization of high-quality activated carbons from hard-shelled agricultural wastes mixture by zinc chloride activation

In this study, a mixture apricot and peach stones, and almond shell, which are hard-shelled agricultural wastes, was evaluated as a precursor for activated carbon synthesis. Effects of the impregnation and pyrolysis conditions on ACs synthesis were investigated. The ACs were characterized by surface area, pore size, pore volume, surface functional groups by Boehm’s titration and FTIR analysis, ash content, pH_pzc, and SEM-EDX. It has been found that the impregnation conditions and pyrolysis temperature have important effect on the microspores formation. ACs having specific surface area in the range of 1,125.73–2,073.04?m²g^?1 and total pore volumes in the range of 0.5498–1.0918?cm³ g^?1 can be synthesized from the mixture activated by ZnCl₂ at impregnation ratios of higher than 15/40. These values are higher than those of the most commercial ACs. Therefore, it can be concluded that the mentioned wastes mixture is a promising precursor for producing high-quality ACs.     

Synthesis, formulation, and characterization of siloxane–polyurethane coatings for underwater marine applications using combinatorial high-throughput experimentation

Crosslinked siloxane–polyurethane coatings were designed, synthesized, formulated, applied, and characterized using combinatorial high-throughput experimentation and eight coatings were selected as candidates for further characterization. First, 72 novel hydroxyalkyl carbamate and dihydroxyalkyl carbamate-terminated poly(dimethylsiloxane) (PDMS) oligomers and their carbamate-linked block copolymers with poly(ε-caprolactone) (PCL) were synthesized using a high-throughput synthesis system. These PDMS oligomers and block copolymers were characterized for their molecular weight using high-throughput Gel Permeation Chromatography (Rapid-GPC). The 72 oligomers were then incorporated into siloxane–polyurethane formulations at four different levels resulting in 288 coatings. After initial screening of these 288 coatings, eight coatings were selected for further characterization. Differential scanning calorimetry, dynamic mechanical analysis, X-ray photoelectron spectroscopy and surface energy analysis demonstrate the presence of PDMS on the surface with a polyurethane underlayer. Pseudo-barnacle adhesion and the attachment strength of reattached live barnacles (Balanus amphitrite) were in good agreement. Out of the eight coatings that were down-selected, two coatings performed well in algal (Ulva), bacterial (Cytophaga lytica, Halomonas pacifica), and barnacle (Balanus amphitrite) laboratory screening assays and are potential candidates for ocean testing. This paper was awarded Second Place in the 2006 Roon Awards competition, held as part of the FutureCoat! conference, sponsored by the Federation of Societies for Coatings Technology, in New Orleans, LA, on November 1-3, 2006.     

Extraction and identification of an antioxidative component from peanut hulls

Methanol extraction of hulls from Tainan select no. 9 (P-9) and Tainan no. 11 (P-11) peanuts produced a higher yield of a component having stronger antioxidant activity (AOA) than other organic solvents. The AOA of methanolic extracts from peanut hulls was equal to butylated hydroxyanisole and stronger thanα-tocopherol. The methanolic extract from peanut (P-11) hulls was separated into 18 fractions by thin-layer chromatography (TLC). High antioxidant activity was found in subfractions with R_fs of 0.20, 0.25, 0.28, 0.31 and 0.37 at 95.6%, 93.8%, 94.7%, 92.0% and 81.6% inhibition of peroxidation of linoleic acid, respectively. Further purification of the subfraction eluting at 0.20 yielded a compound with antioxidant activity of 94.8%. Based on high-performance liquid chromatography (HPLC) analysis, ultraviolet (UV) spectra and¹H nuclear magnetic resonance (NMR), this compound was identified as luteolin.