Degradation of paracetamol by Pseudomonas aeruginosa strain HJ1012.

Pseudomonas aeruginosa strain HJ1012 was isolated on paracetamol as a sole carbon and energy source. This organism could completely degrade paracetamol as high as 2200 mg/L. Following paracetamol consumption, a CO2 yield rate up to 71.4% proved that the loss of paracetamol was mainly via mineralization. Haldane's equation adequately described the relationship between the specific growth rate and substrate concentration. The maximum specific growth rate and yield coefficient were 0.201 g-Paracetamol/g-VSS·h and 0.101 mg of biomass yield/mg of paracetamol consumed, respectively. A total of 8 metabolic intermediates was identified and classified into aromatic compounds, carboxylic acids, and inorganic species (nitrite and nitrate ions). P-aminophenol and hydroquinone are the two key metabolites of the initial steps in the paracetamol catabolic pathway. Paracetamol is degraded predominantly via p-aminophenol to hydroquinone with subsequent ring fission, suggesting partially new pathways for paracetamol-degrading bacteria.

Treatment of a BTo-X-contaminated gas stream with a biotrickling filter inoculated with microbes bound to a wheat bran/red wood powder/diatomaceous earth carrier.

Microbes bound to a wheat bran/red wood powder/diatomaceous earth carrier were used as inoculants for a biotrickling filter (BTF) for treating gases contaminated with a mixture of benzene, toluene, and o-xylene (BTo-X). An overall removal efficiency of more than 87.9% was achieved after a start-up period of as low as 4days. At BTo-X loading rates (LRs) below 60.0g/m(3)h, the BTF's performance was similar for EBRTs of 90, 60, 45 and 30s with an elimination capacity (EC) almost approaching the LR; stable REs above 91.3% for benzene and toluene and above 82.8% for o-xylene were achieved. A maximum EC of 97.7g/m(3)h was obtained at inlet load of 146.4g/m(3)h. The mass ratio of carbon dioxide produced to the BTo-X removed was approximately 2.62, which confirmed complete degradation of BTo-X. The results demonstrate that microbes bound to a solid carrier can be an alternative to traditional liquid inoculums applied in BTFs and highlight their potential applicability to BTF technologies.