Steady- and transient-state performance of a thermophilic suspended-growth bioreactor for α-pinene removal from polluted air

• α-Pinene removal from polluted air was examined under thermophilic conditions.
• One- and two- liquid phase CSTBs were tested for steady and transient performances.
• Addition of 5% (v/v) silicone oil enhanced CSTB performance (ECmax – 85.7 g m−3 h−1).
• Both CSTBs showed good resilience capacity during shock-load tests.
• Specific α-pinene utilization rate of the thermophilic microorganisms was estimated.

The removal of α-pinene from polluted air was examined under thermophilic conditions (50 °C) in one- and two-liquid phase continuous stirred tank bioreactors (CSTBs). Steady-state experiments were performed at different gas residence times, and α-pinene concentrations, corresponding to inlet loading rates between 0.5 and 38 g m−3 h−1 in the one-liquid phase CSTB, and between 2.9 and 176 g m−3 h−1 in the two-liquid phase CSTB. The presence of a second liquid-phase (5% v/v silicone oil) increased the maximum elimination capacity (85.7 g m−3 h−1) by ∼6-fold compared to the one-liquid phase CSTB. During transient-state experiments, the CSTB with silicone oil could withstand a higher α-pinene shock load (110 g m−3 h−1) than the CSTB operated without silicone oil (70 g m−3 h−1). Besides, the thermophilic specific substrate utilization rates were estimated from batch assays, reaching 89 and 340μgα-pinenemgbiomass-1d-1, in the absence of or presence of silicone oil, respectively.