A microfluidic device for pH gradient chromatofocusing is presented, which performs creation of a micro-column, pH gradient generation, and fraction collection in a single device. Using a sieve micro-valve, anion exchange particles were packed into a microchannel in order to realize a solid-phase absorption column. To fractionate proteins according to their isoelectric points, elution buffer solutions with a stepwise pH gradient were prepared in 16 parallel mixing reactors and flowed through the micro-column, wherein a protein mixture was previously loaded. The volume of the column is only 20 nL, hence it allows extremely low sample consumption and fast analysis compared with a conventional system. We demonstrated separation of two proteins, albumin–fluorescein isothiocyanate conjugate (FITC-BSA) and R-Phycoerythrin (R-PE), by using a microcolumn of commercial charged polymeric particles (Source 15Q). The microfluidic device can be used as a rapid diagnostic tool to analyse crude mixtures of proteins or nucleic acids and determine adsorption/desorption characteristics of various biochemical products, which can be helpful for scientific fundamental understanding as well as instrumental in various industrial applications, especially in early stage screening and process development.@en

This paper describes the design, modelling and experimental characterization of an electrochemical sensor array for on-line monitoring of fermentor conditions in a miniaturized cell assay. The sensor array is capable of monitoring viable yeast concentration, dissolved oxygen concentration, pH and temperature.@en

There is a growing interest in developing minute laboratories on a 'chip' (Lab-on-a-Chip) and micro-(bio)chemical reactors as clearly shown by the research efforts of many industrial companies and research institutes in recent years. The development of a new technological platform for fed batch fermentations in very small volume (10-300 μl) reactors in an array format will be described, which in the end will allow to improve production properties of micro organisms by rapid screening under industrially relevant conditions. One of the objectives (besides developing sensing technology) is to design and test methods to analyze and control mixing. This presentation addresses several mixing methods that can be used in micro-bioreactors. The micro-bioreactor is operated under extreme conditions like high biomass and product concentrations, high oxygen requirement and long residence time (3-4 days). With the help of Computational Fluid Dynamics simulations, the influence of the mixing method on the fermentation efficiency in the microreactor is described. These results will be supported by real-life experimental mixing data.@en