<p>Transport phenomena in rotating disk systems play an important role in many engineering applications such as rotating disk reactors, disc drilling bits, and bio-microfluidic devices; therefore, this article evaluates the electrically conducting Carreau nanofluid motion between rotating disk surfaces, integrating motile microbes and bidirectional reactions, with regard to the influence of nonlinear radiation, thermal diffusion, and Ohmic dissipation. The intricate nature of the PDEs is framed in consideration of boundary layer approximations by utilizing a similarity transformation. The appropriate conversions of transformation functions are specified and executed to recast the set of PDEs into highly nonlinear ODEs (Ordinary Differential Equations). Then, the Spectral Quasi-Linearization Methodology (SQLM) is adopted to numerically describe the dimensionless expressions of the ODEs. Graphic representations for liquid flow, temperature, concentration, and microbial concentration distributions are plotted. Computational and semi-analytical results detailing the parametric influences on physical variables are presented in a tabular format. A comparison with a literary work is also undertaken to ensure the validity of the modeled system. The results show that the primary velocity decreases with the magnetic field parameter but increases with the rotation and stretching parameters. The temperature rises with Brownian motion and thermophoresis, while the concentration decreases with higher Lewis number and chemical reaction parameter.</p>