Microbial physiological state at low growth rate in natural and engineered ecosystems.

Microbes often grow in nature and bioreactors at very low growth rates. However, the physiological consequences at low growth rates have not been explored as completely as at faster growth rates or under starvation conditions. Nutrient flux to (and through) the cell surface and non-growth-dependent energy consumption (maintenance) are important considerations under these conditions. The biomass recycle reactor is a system to explore physiological state at low growth rate, and to optimize certain industrial process rates.