Anaerobic phenol biodegradation: kinetic study and microbial community shifts under high concentrations dynamic loading

In this study, we provide an extended kinetic study of phenol biodegradation realized in an anaerobic sequencing batch reactor (SBR) operated with a microbial consortium. The process was investigated both in co-metabolic and metabolic conditions, and glucose has been employed as co-substrate in metabolic tests. After the acclimatization phase, the co-metabolic process was investigated at increasing phenol load (up to 2000 mg/L influent concentration), then the glucose was progressively decreased until metabolic conditions where reached and the phenol was fed at the same concentration level. Kinetic models were applied for all the operating conditions and related parameters were evaluated and compared for metabolic and co-metabolic conditions and with previous literature data. The microbial community was characterised through 16S NGS and PICRUSt2 at the different operating conditions to determine 1) the structure and composition of the microbial community developed within the reactor, 2) the effect of the reactor operation on the driving microbial species and 3) the potential functionality of the community in the degradation of phenol at each phase.