Microbial and kinetic characterization of pure and mixed cultures aerobically degrading 4-nitrophenol

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• 作者：Maria Concetta Tomei ; Simona Rossetti and Maria Cristina Annesini
• 关键词：Aerobic degradation ; 4-nitrophenol ; FISH ; SBR
• 刊名：Chemosphere
• 出版年：2006
• 出版时间：June 2006
• 年：2006
• 卷：63
• 期：10
• 页码：1801-1808
• 全文大小：253 K

文摘

The molecular and kinetic characterization of a microorganism able to aerobically degrade 4-nitrophenol (4NP) is presented. The microorganism was isolated from a mixed culture operating in a laboratory-scale sequencing batch reactor with an aerobic anoxic cycle. It was identified as a member of Ralstonia genus within Betaproteobacteria. It is a gram negative coccobacillum (cell length of 2–3 μm) able to aerobically store lipid inclusions when grown aerobically on nitrophenol as the sole carbon source in the range of tested concentrations (80–320 mg l⁻¹). Batch kinetic tests were performed with the pure culture, while the kinetics of the mixed biomass was directly investigated in the reactor. For pure cultures exponential growth was observed, with growth rate values in the range of 2–6 d⁻¹; in experiments with the mixed cultures 4NP concentrations were correlated with growth using the Haldane equation (k_max = 0.30 mg 4NP mg⁻¹ VSS h⁻¹; K_s = 55 mg 4NP l⁻¹ and K_I = 15 mg 4NP l⁻¹). Observed pure culture growth rates were higher than those of mixed cultures. This result can be explained by considering that in mixed culture the biomass is evaluated as volatile suspended solids, including both specialized biomass for 4NP removal and denitrifying bacteria.