Synchrotron FTIR microspectroscopy of Escherichia coli at single-cell scale under silver-induced stress conditions.

The present work was focused on elucidating biochemical changes in the model bacterium Escherichia coli exposed to ionic silver mediated stress, at a single-cell scale. In order to achieve this, in situ synchrotron Fourier-transform infrared (sFTIR) microspectroscopy was performed, for the first time, on individual cells by attenuated total reflectance (ATR) combined with the use of zinc-selenide hemisphere for high spatial resolution. In a first part, the potential of the method was evaluated on bacteria subjected to a lethal 100 μM AgNO(3) concentration for 2 h compared to untreated 100 % viable cells.

Synchrotron FTIR microspectroscopy of the yeast Saccharomyces cerevisiae after exposure to plasma-deposited nanosilver-containing coating.

The present work was focused on elucidating changes in the model yeast Saccharomyces cerevisiae (cell composition, ultrastructure) after exposure to antimicrobial plasma-mediated nanocomposite films. In order to achieve this, a nanosilver-containing coating was deposited onto stainless steel using radiofrequency HMDSO plasma deposition, combined with simultaneous silver sputtering. X-ray photoelectron spectroscopy (XPS) confirmed the presence of silver nanoparticles embedded in an organosilicon matrix.

Why and how membrane bioreactors with unsteady filtration conditions can improve the efficiency of biological processes.

A membrane bioreactor (MBR), an association of a bioreactor with a crossflow filtration unit, enables continuous processes with total cell retention within the reactor to be realized. Provided that high dilution rates can be applied and that inhibition processes are avoided, very high biomass concentrations can be reached, thereby improving the volumetric productivities. These membrane bioreactors have been successfully applied to various microbial bioconversion, such as alcoholic fermentation, solvents, organic acid production, starters, and wastewater treatment.

Feasibility study of a compact process for biological treatment of highly soluble VOCs polluted gaseous effluent.

Volatile organic compounds (VOCs), representing a wide range of products mainly generated by industrial activity, are involved in air pollution. This study deals with a new biological treatment process of gaseous effluent combining a gas/liquid contactor called an "aero-ejector" and a membrane bioreactor. Combining these two innovative technologies enables a high elimination efficiency to be reached.

Influence of a transverse flowrate on the oxygen transfer performance in heterogeneous aeration: case of hydro-ejectors.

This paper deals with the scaling of aeration devices, and more specifically hydro-ejectors, in the case of heterogeneous aeration. Because the transfer of oxygen only occurs in a very small part of the volume of the treatment basin, the transfer performance of the aerator depends on the device itself and on the surrounding flow characteristics. First experiments were achieved with a 10 L mechanically agitated reactor in order to operate at a known kLa and liquid flowrate Q.