The Kinetics of Interesterfication on Waste Cooking Oil (Sunflower Oil) for the Production of Fatty Acid Alkyl Esters using a Whole Cell Biocatalyst (Rhizopus oryzae) and Pure Lipase Enzyme

Recent research and technology have provided promising outcomes to rely on biodiesel as the alternative and conventional source of fuel. The use of renewable sources constitutes the main stream of research. Waste Cooking Oil (WCO) was used for biodiesel production in this study. Lipase enzyme producing fungi Rhizopus oryzae 262 and commercially available pure lipase enzyme were used for comparative study in the production of FAAE. The whole cell biocatalyst and pure enzyme were immobilized using calcium alginate beads. It was prepared by optimizing with different molar ratios of calcium chloride and different percent sodium alginate. Entrapment immobilization was done for whole cell biocatalyst. PE was also immobilized by entrapment for the transesterification reaction. Four different solvents methanol, ethanol, n-propanol, n-butanol were used as the acyl acceptors. The reaction parameters like temperature, molar ratio, reaction time, and amount of enzyme to be used were also optimized for methanol alone. The same parameters were adopted for the other acyl acceptors too. Among the different acyl acceptors, methanol whose reaction parameters were optimized showed maximum conversion of triglycerides to FAAE - 94% with PE and 84% with WCB. On the whole, PE showed better catalytic converting ability with all the acyl acceptor compared to WCB, further study, it was observed that three consecutive and reversible reactions occurred in the interesterification of triglycerides. So, a kinetic model based on Michaelis-Menten equation with competitive substrate inhibition was used to find the maximum reaction rate V_i for the four solvents using pure enzyme and WCB.     

土壤中酞酸酯类化合物监测方法的质量控制研究

从监测结果控制的角度对近10年的土壤中PAEs监测方法进行了探讨,重点比较了索氏萃取柱净化GC/MS、微波萃取柱净化GC、加速溶剂萃取柱净化GC/MS和加速溶剂萃取GPCGC/MS方法的检出限、精密度和准确度。旨在为中国土壤监测方法的建立提供基础支撑,为开展质量控制工作提供评价依据。     

Role of esters in egg removal behaviour in honeybee (Apis mellifera) colonies

In queen-right honeybee colonies workers detect and eat the vast majority of worker-laid eggs, a behaviour known as worker policing. However, if a colony becomes permanently queen-less then up to 25% of the worker population develops their ovaries and lay eggs, which are normally reared into a final batch of males. Ovary development in workers is accompanied by changes in the chemical secretion of the Dufour's gland with the production of queen-like esters. We show that ester production increases with the period that the colony is queen-less. The increased ester production also corresponds to an increase in persistence of worker-laid eggs in queen-right colonies, since the esters somehow mask the eggs true identity. However, in a rare queen-less colony phenotype, workers always eat eggs indiscriminately. We found that the egg-laying workers in these colonies were unusual in that they were unable to produce esters. This apparently maladaptive egg eating behaviour is also seen in queen-less colonies prior to the appearance of egg-laying workers, a period when esters are also absent. However, the indiscriminate egg eating behaviour stops with the appearance of ester-producing egg-laying workers. These observations suggest that esters are providing some contextual information, which affects the egg eating behaviour of the workers.     

构建湿地去除酞酸酯的基质微生物和酶机制研究

随着塑料制品的广泛使用，酞酸酯的污染越来越引起人们的广泛关注。目前，DBP(邻苯二甲酸二丁酯)和DEHP(邻苯二甲酸二异辛酯)已成为全球最普遍的污染物之一。报告了复合垂直流构建湿地对含酞酸酯(DBP等)的污水污染的去除效果，以及湿地去除酞酸酯的基质微生物和酶方面的净化机理。具体结果如下：复合垂直流构建湿地对酞酸酯污染具有较好的净化效果，去除率高达99．9％以上；构建湿地对酞酸酯的净化主要发生在氧气含量相对较多的下行流池，上行流他的净化作用相对较差；同时分层实验还发现，构建湿地的净化作用主要集中在湿地上层基质中。通过研究，为进一步研究利用构建湿地处理酞酸酯污染提供了有益的参考。     

Explosion regions and limiting oxygen concentrations of methyl propionate,methyl acetate,dimethyl carbonate with air and inert gas mixtures

New data about explosion regions with special focus on limiting oxygen concentrations for methyl propionate, methyl acetate, dimethyl carbonate with air in the presence of nitrogen, helium and carbon dioxide were determined at ambient initial pressure and 423 K. The measurements were executed according to EN 1839 method T. The changes of the explosion regions with temperature and type of inert gas were also modeled mathematically using an extended calculated adiabatic flame temperature profile (CAFTP) method. The shift of the explosion region boundaries with temperature when switching from nitrogen to carbon dioxide were reproduced well. For a switch to helium a good agreement could be reached only if the very high thermal conductivity of helium had been considered properly by using the Lewis number. This requires the knowledge of the respective Lennard-Jones parameters. The LOC of helium-containing mixtures can, however, be calculated with acceptable accuracy even if the Lennard-Jones parameters of the flammable substance are not known exactly by using reasonable estimations.     

土壤中邻苯二甲酸酯类检测空白研究

通过气质联机法检测六种主要的邻苯二甲酸酯类(PAEs),对土壤中PAEs检测过程中各个环节进行了空白影响的测定.实验表明,邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)三种物质对空白造成的影响较大.试剂污染是土壤中PAEs检测空白偏高的主要原因.而在不同的前处理方法中,水浴浓缩对空白的污染最小.