Mechanism of Cell Proliferation During Starvation in a Continuous Stirred Tank Anaerobic Reactor Treating Food Waste
Although anaerobic digestion is a mature technology, the mechanism of cell proliferation during starvation has not yet been clarified. In this study, a continuous stirred tank reactor (CSTR) treating food waste was exposed to deliberate starvation for 12 days. The cell density and the variability of digestate characteristics during starvation were monitored. It was found that starvation increased cell density from 2.8 × 10 10 cells mL −1 to 7.9 × 10 10 cells mL −1 within 2 days and reduced the residual substrate. The carbon and nitrogen mass balances showed that this increase in cell density was due to residual substrate consumption because of the shift of the microorganisms’ substrate preference to these other available sources as the easily degradable substrate was exhausted. The prolonged starvation of more than approximately 3−6 days induced an increase in the free ammonia concentration to an inhibitive level of more than 0.10 g-N L −1 for anaerobic digestion microorganisms due to the excessive ammonification of residual nitrogen, thereby resulting in a drastic decrease in cell density. Our results demonstrated that a deliberate starvation operation in an appropriate timeframe applied to a CSTR treating food waste could be beneficial to proliferate cells and, at the same time, reduce residual substrate
Year of publication: |
[2021]
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Authors: | Akizuki, Shinichi ; Joo, Hiromi ; Koyama, Mitsuhiko ; Toda, Tatsuki |
Publisher: |
[S.l.] : SSRN |
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