The waste product of the Krebs cycle, also known as the citric acid cycle, is primarily carbon dioxide (CO2). During this cycle, which occurs in the mitochondria of cells, acetyl-CoA is oxidized to produce energy in the form of ATP, along with other byproducts.
As the cycle progresses, carbon atoms from the acetyl-CoA are released as CO2 during several steps of the process. This carbon dioxide is then transported out of the cell and ultimately exhaled through the lungs as a waste product of cellular respiration.
In summary, the main waste product of the Krebs cycle is carbon dioxide, which is a natural outcome of breaking down nutrients for energy in aerobic organisms.