The response of Pseudomonas putida F1 to process fluctuations and operational failures during toluene biodegradation was evaluated in a chemostat suspended growth bioreactor. The ability of P. putida F1 to rapidly increase its specific toluene degradation capacity resulted in no significant variation in process removal efficiency when toluene load was increased from 188 to 341 g m(-3) h(-1). Likewise, bacterial activity rapidly reached steady state performance (in less than 1.5 h after the restoration of steady state operational conditions) following an 8 h process shutdown, or after episodes of toluene or mineral nutrients deprivation. Process performance was however highly sensitive to pH, as pH levels below 4.5 dramatically inhibited bacterial activity, decreasing severely process robustness and inducing a cycle of periodic process collapses and recoveries. This pH mediated deterioration of bacterial activity was confirmed by further respirometric tests, which revealed a 50-60% reduction in the O(2) consumption rate during the degradation of both toluene and 3-methyl catechol when pH decreased from 5.05 to 4.55. Finally, process robustness was quantified according to methods previously described in literature.

中文翻译：

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恶臭假单胞菌F1培养物对波动的甲苯负荷和悬浮生长生物反应器操作失败的反应。

在恒化器悬浮生长生物反应器中评估了恶臭假单胞菌F1对甲苯生物降解过程中的波动和操作失败的响应。当甲苯负荷从188 gm（-3）h（-1）增加时，恶臭假单胞菌F1快速提高其特定甲苯降解能力的能力不会导致工艺去除效率发生显着变化。同样，在关闭过程8小时后，或甲苯或矿物质营养缺乏后，细菌活性迅速达到了稳态性能（在恢复稳态操作条件后不到1.5小时内）。然而，工艺性能对pH高度敏感，因为pH值低于4.5会显着抑制细菌活性，严重降低了过程的鲁棒性，并导致周期性的过程崩溃和恢复。此pH值介导的细菌活性下降已通过进一步的呼吸测试得到证实，该实验表明，当pH从5.05降至4.55时，甲苯和3-甲基邻苯二酚的降解过程中O（2）消耗率降低了50-60％。最后，根据先前文献中描述的方法对过程的鲁棒性进行了量化。