What are the differences between batch and fed-batch fermentation?

In batch fermentation, all nutrients are added at the start and the process runs until completion without additions. It is simple to operate but limited by nutrient depletion and toxic metabolite accumulation. In fed-batch fermentation, nutrients (carbon source, nitrogen, etc.) are added during cultivation based on demand, extending the productive phase and achieving higher cell densities and product titers. Fed-batch avoids substrate inhibition and overflow metabolism. It requires more sophisticated control but typically yields 3-10 times higher product concentrations. Fed-batch is the dominant mode for industrial protein and antibiotic production.