Biodegradation characterisation and kinetics of m-cresol by &lt;i&gt;Lysinibacillus cresolivorans&lt;/i&gt;

H Yao,Y Ren,S Yue,C Wei

doi:10.4314/wsa.v37i1.64101

Biodegradation characterisation and kinetics of m-cresol by <i>Lysinibacillus cresolivorans</i>

H Yao, Y Ren + Show 2 more

Open Access

https://doi.org/10.4314/wsa.v37i1.64101

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Abstract

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 35°C. 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 μmax = 0.89 h-1, Ks = 426.25 mg·l-1, Ki = 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. Keywords: m-cresol; biodegradation; Lysinibacillus cresolivorans; high efficient degrading bacterium

Highlights

Phenolic compounds are environmental pollutants because of their wide distribution and detection in the effluent of various industrial operations, which include petrochemicals, textile, dying, varnish industries, phenolic resin manufacturing and steel plants (Jiang et al, 2006; Juang and Tsai, 2006)
Morphological and biochemical analyses, including 16S rRNA gene sequence comparisons, demonstrated that the selected strain belongs to a novel species, Lysinibacillus cresolivorans
Lysinibacillus cresolivorans suspension was inoculated into mineral salts medium (MSM) (10%, v/v) containing 52.76 mg·l-1 m-cresol at exponential phase (OD = 0.083)

Summary

Introduction

Phenolic compounds are environmental pollutants because of their wide distribution and detection in the effluent of various industrial operations, which include petrochemicals, textile, dying, varnish industries, phenolic resin manufacturing and steel plants (Jiang et al, 2006; Juang and Tsai, 2006). We can see that Lysinibacillus cresolivorans utilised m-cresol as its sole source of carbon and energy, and growth of bacteria is closely related to the biodegradation of m-cresol. Batch cultures of Lysinibacillus cresolivorans were inoculated in MSM containing m-cresol as the sole carbon and energy source, in order to obtain the biodegradation kinetic model parameters of m-cresol. The results clearly showed good ability in biodegrading m-cresol, even at high concentrations, when employing Lysinibacillus cresolivorans.

Results

Conclusion