BACKGROUND Microfluidics offers itself as a potential platform for optimizing microbial growth in different substrate concentrations using a single assay. The aim of this study was to construct a reversible microfluidic device for monitoring the bacterial growth in chambers with different substrate concentrations with its respective technical triplicates. The convective concentration gradient generator (CCG) system was constructed with three inlets for solutions with different concentrations that distributed them to the sequential cultivation chambers (CCs). A perfusion microbioreactor system (PM) was constructed using a commercial polydimethylsiloxane (PDMS) sheet and glass, with an adapted semi-permeable membrane system to constrain the cells within the CC. Cell growth of a fluorescent Escherichia coli JM109 was monitored by fluorescence microscope with time-lapse technique. RESULTS The growth profile of E. coli with different streptomycin concentrations and its specific growth rates (mu(x)) in the microfluidics device (mu(x) of 0.0088 and 0.0092 h(-1)) were compared in batch cultivations, which show no significant difference between the two methods. In addition, the half maximal inhibitory concentration (IC50) values indicate that continuous perfusion surpasses consumption of the tested drug. CONCLUSION The results demonstrate the efficiency of the microfluidic device for cell cultivation and its applicability in industrial biotechnology, allowing rapid screening of multiple parameters. (c) 2018 Society of Chemical Industry