A highly effective active micro mixer utilizing magnetic force with a simple configuration is explored to facilitate the fast mixing of more than two fluid flows and to integrate a microfluidic system capable of disrupting cells and reacting with biomolecules. The mixing performance of the active micro mixer is evaluated within an aqueous-aqueous system including dyes for visual observation and within an organic-aqueous system where enzyme reaction occurs. In addition, this magnetic stirrer for microfluidic-based research is used to create complete analytical micro systems, which facilitates cell lysis, sample preparation, and a subsequent analysis of intracellular biomolecules. Upon loading a sample of a whole cell and lysis reagent into a mixing chamber, the integrated microfluidic device carries out cell disruption by rotation of a micro magnetic-disc. Intracellular lipase samples from lyzed cells can be efficiently mixed and reacted with its substrate. We developed a micro-mixing fluidic system for cell lysis and enzyme reaction in order to detect colorimetric products.