Linking microbial respiratory activity with phospholipid fatty acid of biofilm from full-scale bioreactors

Deficiency of researches on biotic community-driven biofilm activity makes biofilm regulation lack of quantitative response for decades. Based on three full-scale aerobic bioreactors in wastewater treatment plants, this study for the first time linked microbial respiratory activity with phospholipid fatty acid (PLFA) of biofilm developed on fixed and suspended carriers. Results showed that C16:00, C18:00, C16:1, ω7c, C18:1, ω7c, C12:00 and C18:1ω9c were top six biomarkers of PLFA among different sources of samples and Gram-negative bacteria (G-) was more abundant than Gram-positive bacteria (G+) with average G-/G+ of 2.98. It's interesting to find defective revealing of PLFA-based biofilm activity by specific oxygen uptake rate (SOUR). Further modeling indicated that C16:00 achieved the optimal quantitative response to STOUR with the best model of composite, growth, or exponential curve (R² = 0.416, p = 0.005). This research was promising to provide important reference for biofilm regulation and accurate control of biofilm-based process.