Effect of mass transfer on biodesulfurization kinetics of alkylated forms of dibenzothiophene by Pseudomonas putida CECT5279

BACKGROUND: An important problem exists for the implementation of biodesulfurization technology of fuels related to the influence of mass transfer on the overall reaction rate and process yield. Pseudomonas putida CECT5279 has been shown to be one of the most promising biocatalysts, but most kinetic studies were done at small scale and their capability for the transformation of alkyl substituted forms (Cx–DBTs) has not yet been reported. RESULTS: Conversion yields and kinetic parameters were calculated under aqueous and biphasic resting cell conditions in a 2 L stirred tank reactor. In aqueous reaction media, 100% conversion of DBT, 4MDBT and 4,6DMDBT was achieved while the conversions in the presence of an organic liquid were 38% for DBT, 19.5% for 4MDBT and 16.5% for 4,6DMDBT, showing that the process is strongly affected by mass transfer between liquids. Laboratory scale–up of P. putida CECT5279 growing step was successfully carried out using a 15 L stirred tank, on the basis of the volumetric mass transfer coefficient (k_La). CONCLUSIONS: P. putida CECT5279 is capable of removing Cx–DBT compounds successfully in aqueous resting cell conditions using stirred tank reactors, but in biphasic media, mass transfer between liquids controls the process, increasing time of reaction and lowering process yield. © 2012 Society of Chemical Industry     

恒电量技术及其在油液污染监测中的应用

介绍了恒电量技术的基本原理，分析了恒电量技术在油液污染度在线检测中的应用方法，提出了基于微机的油液污染度监测方案。