Resumo

YAO, Haiyan; REN, Yuan; WEI, Chaohai  e  YUE, Siyang. Biodegradation characterisation and kinetics of m-cresol by Lysinibacillus cresolivorans. Water SA [online]. 2011, vol.37, n.1, pp.15-20. ISSN 1816-7950.

A novel strain of m-cresol-degrading bacterium, named as Lysinibacillus cresolivorans, was isolated from aerobic sludge from a coking wastewater treatment plant. This bacterium is able to utilise m-cresol as its sole source of carbon and energy. The optimal pH for growth is 6.8 ~ 7.3 and the optimal temperature is 35ºC. Compared to organic nitrogen sources, inorganic nitrogen sources were easily utilised for the m-cresol biodegradation. The degradation rate of m-cresol at different starting concentrations was analysed with zero-order kinetic characteristics. When the initial concentration of m-cresol was 224.2 mg·ℓ^-1, the reaction rate reached a maximum at 46.80 mg·(ℓ·h)^-1.The cell growth kinetics was also investigated with initial m-cresol concentrations varying from 0 to 1 200 mg·ℓ^-1. The growth kinetics was well described by the Haldane kinetic models. The parameter values of m-cresol on cell growth were µ_max = 0.89 h^-1, K_s = 426.25 mg·ℓ^-1, K_i = 51.26 mg·ℓ^-1. Experiments supplementing growth with glucose indicated that this substrate increased the biomass, and also induced the biodegradation of m-cresol. From the results, it can be concluded that Lysinibacillus cresolivorans is an efficient m-cresoldegrading bacterium and that glucose plays multiple roles in the co-substrate condition.

Palavras-chave : m-cresol; biodegradation; Lysinibacillus cresolivorans; high efficient degrading bacterium.

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