Involvement of ATP and autoinducer-2 in aerobic granulation.

Aerobic granulation represents an important bacterium-to-bacterium self-immobilization process that has been exploited for the treatment of a wide spectrum of wastewaters, but the mechanism behind still remains unclear in a microbiological sense. This study investigated the possible involvement of ATP and autoinducer-2 (AI-2) in aerobic granulation. Results revealed that initiation of microbial aggregation is closely associated with the ATP content of biomass, whereas AI-2 of biomass would be essential for maturation of aerobic granules. Furthermore, it was found that the AI-2-associated coordination of microorganisms in microbial aggregates would be biomass density dependent. This study clearly shows the involvement of ATP and autoinducer-2 in aerobic granulation, and may be exploited further for enhancement or prevention of microbial aggregation in general, for example, rapid granulation for wastewater treatment or inhibition of biofouling in membrane bioreactor.