Purification and characterization of a novel bacteriocin CAMT2 produced by Bacillus amyloliquefaciens isolated from marine fish Epinephelus areolatus

A novel bacteriocin named CAMT2 was produced by strain ZJHD3-06 which was isolated from the marine fish Epinephelus areolatus and identified as Bacillus amyloliquefaciens, Bacteriocin CAMT2 inhibits important food spoilage and food-borne pathogens such as Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and Vibrio parahaemolyticus. Bacteriocin CAMT2 was purified by ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-50 and reversed phase chromatography on a C₁₈ column. The molecular mass of the purified bacteriocin CAMT2 was about 20.0 kDa and N-terminal sequencing of the peptides revealed low similarity with existing antimicrobial peptides, as determined by an LC–MS/MS system. Bacteriocin CAMT2 was resistant for up to 100 °C and pH ranging 2–10, but lost its activity when treated with protease K. The bacteriocin also showed significant antimicrobial activity against L. monocytogenes in a meat model system. These obtained results suggest that bacteriocin CAMT2 has potential for use as a food biopreservative.     

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长庆气田第一净化厂从德国Linde公司引进了一套采用Clinsulf-o工艺的硫磺回收装置，用以处理1200×104m3/d  MDEA脱硫装置产生的酸性气体，该酸气H₂S含量为1.3%～3.4%（摩尔分数）。装置于2004年4月底建成投产，截至目前装置运行情况良好，实际硫回收率平均为94.85%，硫磺纯度为99.9%，排放尾气中的H₂S含量和CO₂含量均符合我国当前的排放标准。     

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在对MDEA溶液中各种杂质组分的分析基础上，通过发泡实验考察了操作条件及各种杂质组分对溶液发泡性能的影响。随着MDEA浓度、MDEA溶液温度的逐渐降低，发泡高度及消泡时间逐渐增大；另外随着通气流率和溶液中CO₂负荷的增大，MDEA溶液发泡高度及消泡时间也逐渐增大。考察了NaCl、CaCl₂、FeSO₄无机盐对MDEA溶液发泡性能的影响。MDEA溶液中有机杂质甲醇、三甘醇、重烃对MDEA溶液则具有一定的消泡作用，而气井缓蚀剂无疑是强的发泡剂。残液的加入使纯净的MDEA溶液发泡性能大幅度地增加，验证了MDEA溶液受到了污染是造成溶液发泡的主要原因。最后对MDEA溶液发泡提出了相应的处理措施和建议。     

Purification of novel bacteriocin produced by Lactobacillus coryniformis MXJ 32 for inhibiting bacterial foodborne pathogens including antibiotic-resistant microorganisms

Bacteriocins produced by LAB comprise a variety of antimicrobial proteins or peptides which can be used as food biopreservatives and/or possible antibiotic alternatives. Bacteriocin-producing Lactobacillus coryniformis MXJ 32, which was identified based on its 16S rRNA gene sequence, was isolated from a traditional fermented vegetable (Jiangshui Cai) of Xixiang county, Shaanxi province, China. Thereafter bacteriocin (designated as lactocin MXJ 32A) produced by L. coryniformis MXJ 32 was purified by ammonium sulfate precipitation, dialysis and ion exchange chromatography. The molecular mass of lactocin MXJ 32A was 3520 Da determined by LC-ESI/MS and the N-terminal sequence of lactocin MXJ 32A was NH₂-GEPGPMGPAGAD. Lactocin MXJ 32A had a broad antimicrobial spectrum including many Gram-positive and Gram-negative foodborne pathogens, in which even some antibiotic-resistant foodborne pathogenic strains could also be inhibited. The MIC of lactocin MXJ 32A for Staphylococcus aureus and Escherichia coli was 10 mg/mL. Lactocin MXJ 32A showed good pH-stability and heat stability and was sensitive to proteolytic enzymes. It was shown by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) that the possible mode of action of lactocin MXJ 32A was pore formation of the cytoplasmic membrane of target cells.     

Isolation,chemical composition and antioxidant activities of a water-soluble polysaccharide from Cyclocarya paliurus (Batal.) Iljinskaja

A water-soluble polysaccharide was isolated from the water extract of Cyclocarya paliurus (Batal.) Iljinskaja, which is a well-known native health tea in China. This polysaccharide was named as CPP-1. The molecular weight of CPP-1 was determined by high-performance gel permeation chromatography, with an average molecular weight of about 1167 kDa. The analysis of monosaccharide composition in the polysaccharide by gas chromatography revealed that it was a heteropolysaccharide and consisted of d-xylose, l-arabinose, d-glucose, d-galactose, l-rhamnose and d-mannose in a molar ratio of 1.00:9.67:9.65:4.96:3.29:2.70. Furthermore, CPP-1 contains 8.44% of protein and 17 general amino acids, and it is rich in glutamic acid, asparagic acid, leucine, glycine, arginine, tyrosine and alanine. The antioxidant activity of CPP-1 was also evaluated. It was found that CPP-1 exerted significant scavenging effects on DPPH radicals with a value of around 91.4%, compared to the reference controls of BHT (91.2%) and ascorbic acid (98.9%) at a concentration of 400 μg/ml, and with EC₅₀ values of 52.3 μg/ml.     

Dynamic measurements of hydrogen reaction with LaNi5−xSnx alloys

The study focuses on the reaction between hydrogen gas and LaNi_5−xSn_x alloys, where 0 ≤ x ≤ 0.5, in broad temperature and pressure ranges. It was performed by means of dynamic volumetric techniques using specific equipment developed at our laboratory. The substitution of Ni by Sn lowers the system equilibrium pressure and increases the hydrogen absorption reaction rate. Reaction pressures at room temperature range from 8 kPa (x = 0.5) to 250 kPa (x = 0). At 415 K the reaction pressure is within the range from 200 kPa to 4000 kPa for x = 0.5 and 0, respectively. The measured characteristic absorption time at 750 kPa for LaNi₅ is around 1 min, while it remains below 2.5 s for LaNi_4.5Sn_0.5. The maximum H concentration goes from 1.3 wt.% for LaNi₅ down to 0.95 wt.% for LaNi_4.5Sn_0.5. These results are useful to identify a metal system where the hydrogen interaction equilibrium properties can be tuned in a wide pressure range by choosing the chemical composition and the process temperature.     

三元混合液及含油污水净化装置与处理工艺

分层注聚、三元复合驱采油等试验过程中产生的废液难以处理,如不及时进行合理的处理,将严重污染环境。大庆油田采油工程研究院开发了三元混合液及含油污水处理工艺技术,研制出三元混合液及含油污水净化装置。三元混合液及含油污水经过物理和化学方法等多道处理工艺,如浓硫酸+双氧水+硫酸亚铁的方法,处理后的废液指标达到GB 8978-1996《污水综合排放标准》中规定的二级排放标准,达到了环保治理的目的。     

烟草内切多聚半乳糖醛酸酶抑制蛋白分离纯化研究

首次报道烤烟中存在ＰＧＩＰ，并以烤烟苗为材料通过硫酸铵沉淀、离子交换层析和分子筛凝胶过滤等步骤分离得到了ＰＧＩＰ，经高ｐＨＤｉｓｃ－ＰＡＧＥ和ＳＤＳ－Ｄｉｓｃ－ＰＡＧＥ分析为电泳纯，紫外吸收为典型的蛋白质吸收光谱。烤烟ＰＧＩＰ是一种糖蛋白，含糖量为６．０３％，等电点为６．４和６．１。     

青海碱业石灰窑煅烧及窑气净化技术

通过对青海碱业石灰窑及窑气净化设备的计算,在与沿海碱厂进行技术对比的基础上论证了在海拔高度2960m、大气压强71．8kPa的条件下,石灰窑及窑气净化系统的生产能力。     

乙二醇净化处理过滤常数测定及过滤条件研究

乙二醇作为一种低毒、高效和应用工艺简单的水合物抑制剂,在天然气处理、集输过程中得到了广泛的使用;然而在循环再生使用过程中,受高温、氧化、地层水矿物质和设备腐蚀等因素的影响,乙二醇的质量随着装置的运行不断发生变化,防冻效果降低,影响天然气正常生产。为了实现乙二醇现场净化工艺,对乙二醇吸附、吸收和过滤工艺中过滤常数进行测定及研究,经过实验结果确定采用处理剂III-5处理污染乙二醇为最佳净化操作方案,为现场工艺、设备、操作方面提供一些第一手的资料。