This paper investigates the effects of activation energy and nonlinear thermal radiation on the flow, heat, and mass transfer of magneto-bioconvective Eyring–Powell nanofluid due to a stretching sheet. It analyzes the influences of magnetohydrodynamic forces, nonlinear thermal radiation, chemical reactions, and the activation energy of species within the Powell–Eyring nanofluid. Motile microorganisms are introduced alongside nanoparticles to prevent agglomeration and stabilize the suspension. The governing nonlinear partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) using similarity transformations and solved numerically with the RKF45 algorithm in MATLAB. Results indicate that increasing the Powell–Eyring fluid parameter and Grashof number enhances the velocity profile, while the Hartmann number and buoyancy ratio reduce it. Temperature distribution increases with higher thermal radiation, Hartmann, Eckert, Brownian motion, and thermophoresis parameters, but decreases with greater Grashof and Prandtl numbers. The nanoparticle concentration profile declines with increasing Lewis number, chemical reaction, and Brownian motion parameters but rises with thermophoresis and activation energy. The density of gyrotactic microorganisms decreases with higher bioconvection Lewis and Peclet number, concentration deference of motile microorganism parameter, while it increases with the Hartmann number. In table, we are observed that as the
and
values are increases, then skin friction coefficient value are decreases. As the
,
,
,
values are increases, then skin friction coefficient value are increases. In table, we are observed that
,
,
values are increases, then local Nusslet number increases. As the
,
,
,
,
values are increases, then local Nusslet number decreases. In table, we are observed that as the values of
,
,
,
,
,
upsurges, then Sherwood number decreases. In table, we observed that as
values increases, then Local density number decreases. As the
,
,
increases, then Local density number increases. Main objective of the present study is observed from tables and the amount of heat transmission increases by increasing the values of
whereas it declines by increasing the values of
. It is noticed that the rate of mass transmission increases by increasing the values of
whereas it declines by increasing the values of
. Shows an overview of the
observations for different values of
&
. The activation energy significantly impacts the flow and heat transfer characteristics of Magneto-Bioconvective Eyring–Powell Nanofluid, affecting its velocity and temperature profiles. Higher activation energy reduces nanoparticle diffusion, slowing mass transfer, and concentration gradients, which is essential in applications requiring controlled diffusion, such as targeted drug delivery and biochemical processing. Nonlinear thermal radiation enhances the heat transfer rate near a stretching sheet and decreases thermal boundary layer thickness, particularly under high-temperature gradients, making it valuable for high thermal load applications, microfluidic cooling, and industrial heating. Magnetic fields influence bioconvection patterns of gyrotactic microorganisms, either enhancing or hindering heat and mass transfer based on magnetic field strength. The Hartmann number increases flow velocity and reduces temperature gradients, offering control over flow profiles in applications like magnetic-assisted manufacturing and microfluidic devices. The nanoparticle volume fraction notably affects the thermophysical properties and heat and mass transfer behavior of the nanofluid. The findings have critical applications in fields such as biomedical engineering, biomedical applications, and energy conversion devices, where controlled diffusion is essential, and in industrial microfluidics, where efficient heat and mass transfer are required. Simulation results provide insight into optimizing heat and mass transfer processes in practical engineering systems, thermal management systems.
