Significant increase in cyanide degradation by Bacillus sp. M01 PTCC 1908 with response surface methodology optimization

Zohre Javaheri Safa,Mohammadreza Zamani,Saeed Aminzadeh,Mostafa Motallebi

doi:10.1186/s13568-017-0502-2

Zohre Javaheri Safa, Mohammadreza Zamani + Show 2 more

Open Access

https://doi.org/10.1186/s13568-017-0502-2

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Abstract

Cyanide is used in many industries despite its toxicity. Cyanide biodegradation is affordable and eco-friendly. Sampling from cyanide-contaminated areas from the Muteh gold mine and isolation of 24 bacteria were performed successfully. The selected bacteria—‘Bacillus sp. M01’—showed maximum tolerance (15 mM) to cyanide and deposited in Persian Type Culture Collection by PTCC No.: 1908. In the primary experiments, effective factors were identified through the Plackett–Burman design. In order to attain the maximum degradation by Bacillus sp. M01 PTCC 1908, culture conditions were optimized by using response surface methodology. By optimizing the effective factor values and considering the interaction between them, the culture conditions were optimized. The degradation percentage was calculated using one-way ANOVA vs t test, and was found to have increased 2.35 times compared to pre-optimization. In all of the experiments, R2 was as high as 91%. The results of this study are strongly significant for cyanide biodegradation. This method enables the bacteria to degrade 86% of 10 mM cyanide in 48 h. This process has been patented in Iranian Intellectual Property Centre under Licence No: 90533.

Highlights

With the increasing population and development of various industries across the world, soil and groundwater are more prone to contamination than ever before
Cyanide-degrading bacteria were isolated from cyanide-contaminated wastewater and soil from the Muteh gold mine
Screening was performed among 24 isolates, one of which was selected as the best cyanide-resistant bacterium that grows in different concentrations of cyanide within 3 days (Fig. 1)

Summary

Introduction

With the increasing population and development of various industries across the world, soil and groundwater are more prone to contamination than ever before. Cyanide is a carbon–nitrogen radical found in inorganic and organic compounds (Dash et al 2009). Its toxicity is due to its physicochemical properties (Gurbuz et al 2009). Because of the cyano group (–C≡N) of cyanide, there are several different forms of cyanide found in nature (Luque-Almagro et al 2011a; Mirizadeh et al 2014). In the First World War, cyanide was used as a chemical weapon

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Conclusion