Plateauvaihe

Plateauvaihe, also called the plateau phase, is a stage in a cell growth curve during which cell proliferation slows or stops, and the total cell number stabilizes. It follows the exponential or log phase and precedes the decline or death phase. In this phase, net growth is near zero, even though cells may remain viable, and cultures can appear crowded.

Causes of the plateau phase include nutrient depletion, accumulation of waste products, depletion of oxygen or essential cofactors, and changes in pH. In adherent mammalian cultures, contact inhibition from high cell density can trigger a halt in division. In microbial cultures, stationary conditions arise from limited resources and stress responses.

Characteristics of plateauvaihe vary by organism and culture system. Specific growth rate approaches zero; cells may shift to a more quiescent or stress-adapted state, with metabolic reprogramming and altered gene expression. Morphological changes can occur in some cell types, and viability may remain high or gradually decline depending on conditions.

Implications for research and industry include altered metabolism, gene expression, and responses to drugs or inhibitors, which can affect experimental outcomes and product yields. Plateau-phase cultures are common in long-term experiments and marketed bioprocesses, where understanding the plateau helps in optimizing timing and interventions.

Management and optimization strategies involve subculturing or passaging to fresh medium, adjusting inoculum density or feeding regimens in fed-batch or continuous culture, improving oxygenation and pH control, and, in some cases, switching to a different culture configuration to maintain growth or drive cells back into a productive phase.