Alkaline extracellular reduction: isolation and characterization of an alkaliphilic and halotolerant bacterium, Bacillus pseudofirmus MC02
Article first published online: 28 MAR 2012
© 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 112, Issue 5, pages 883–891, May 2012
How to Cite
Ma, C., Zhuang, L., Zhou, S.G., Yang, G.Q., Yuan, Y. and Xu, R.X. (2012), Alkaline extracellular reduction: isolation and characterization of an alkaliphilic and halotolerant bacterium, Bacillus pseudofirmus MC02. Journal of Applied Microbiology, 112: 883–891. doi: 10.1111/j.1365-2672.2012.05276.x
- Issue published online: 10 APR 2012
- Article first published online: 28 MAR 2012
- Accepted manuscript online: 3 MAR 2012 10:05AM EST
- 2012/0047: received 10 January 2012, revised 21 February 2012 and accepted 27 February 2012
- azo dye;
- Bacillus pseudofirmus;
- extracellular reduction;
- Fe(III) oxide;
- humic acids
Aims: To isolate an alkaliphilic bacterium and to investigate its ability of extracellular reduction.
Methods and Results: An alkaliphilic and halotolerant humus-reducing anaerobe, Bacillus pseudofirmus MC02, was successfully isolated from a pH 10·0 microbial fuel cell. To examine its ability of extracellular reduction, AQDS (anthraquinone-2, 6-disulfonae), humic acids (HA) and Fe(III) oxides were chosen as representative electron acceptors. All the experiments were conducted in a pH 9·5 carbonate buffer. The results are as follows: (i) Sucrose, lactate, glucose and glycerol were the favourable electron donors for AQDS reduction by the strain MC02; (ii) The strain had the ability of reducing HA in the presence of sucrose; (iii) It could effectively reduce Fe(III) oxides coupled with sucrose fermentation when AQDS was added as electron shuttle and its Fe(III) reducing capacity ranked as: lepidocrocite (γ-FeOOH) > goethite (α-FeOOH) > haematite(α-Fe2O3); (iv) The strain could decolourize azo dye Orange I.
Conclusions: Bacillus pseudofirmus MC02 was capable of extracellular reduction in AQDS, HA and Fe(III) oxides, and it can be used for decolourizing azo dye (Orange I) in alkaline conditions.
Significance and Impact of the Study: This is the first report of an alkaliphlic strain of B. pseudofirmus capable of extracellular reduction in AQDS, HA, Fe(III) oxides and decolourization of Orange I. This study could provide valuable information on alkaline biotransformation in the printing and dyeing wastewater and saline-alkali soil.