What are the different growth phases in batch fermentation?

Bacterial growth in batch culture follows characteristic phases: Lag phase - adaptation period where cells adjust to new environment, synthesize enzymes, no net growth; Exponential (log) phase - rapid, constant growth rate with unlimited nutrients; Stationary phase - growth rate equals death rate as nutrients deplete and metabolites accumulate, often when product synthesis is highest; and Death phase - cell viability declines due to nutrient exhaustion and toxic accumulation. Understanding growth kinetics (specific growth rate mu, doubling time) is essential for process design. Different products may be growth-associated, partially growth-associated, or non-growth-associated.