What is the process of fed-batch culture?

The process begins with batch fermentation, during which microorganisms engulf nutrients, substrates and/or inducers. Fresh medium is then continuously added through various feed streams. After the initial batch growth phase (following inoculation), nutrients are incrementally added to the fermenter throughout the rest of the fermentation. Next, through adjusting the feed rates during the process, carbon, nutrients, phosphates, nitrogen, inducers or precursors, can be continuously or periodically introduced into the culture. Common feeding strategies include discontinuous feeding and regular continuous feeding of nutrients based on feedback regulation or data of online measured variables correlated with metabolism and cell growth. As fresh nutrients are added, substantial biomass accumulation typically occurs during exponential growth. Control of the growth rate is achieved by adjusting the substrate concentration. Products are collected solely at the end of the fermentation, and the culture volume increases until reaching full capacity.