The collisions between particles and bubbles are crucial to the performance of the flotation process. However, experimental, and numerical data on these collisions, particularly, in turbulent flow are scarce. Therefore, bubble-resolved, and particle-modelled Direct Numerical Simulations were conducted to investigate the collision frequency between particles and bubbles and the factors influencing it. This contribution compares two simulation cases, one where externally forced turbulence and gravity are present, and another one where particle and bubble motion is only governed by gravity. The simulations demonstrate that turbulence significantly increases the particle-bubble collision rate by increasing the relative velocity between particles and bubbles due to turbulence. Furthermore, the presence of isotropic turbulence leads to a more uniform collision angle distribution on the bubble surface. As gravity causes a deterministic component of particle and bubble motion under a preferential direction, particles preferably collide and accumulate at the upper half of the bubble. Under the influence of turbulence, these effects on the particle-bubble collision process are significant. Hence, particles approach the bubble from all sides, leading to an increase in potential collision partners. leading to an increase in potential collision partners.