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

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.

Improvement of Bioethanol Production in Consolidated Bioprocessing (CBP) via Consortium of Aspergillus niger B2484 and Trichoderma asperellum B1581

“…To test the adequacy of the model developed, the numerical optimisation of ethanol production by A. niger B2484 and T. asperellum B1581 were tested, in which the model predictions were compared with the actual outcome for validation purposes (Table 3). To check the optimal points predicted by the software, a series of five replicate experiments were performed and the outcome analysed using a one-sample t-test (Safa et al, 2017). The values of the predicted amount of ethanol showed no significant difference to the actual amount of ethanol produced, confirming that the experimental values were in agreement with the predicted values, thus the model was validated.…”

Uncovering Competitive and Restorative Effects of Macro- and Micronutrients on Sodium Benzoate Biodegradation

“…NH 4 Cl, MgSO 4 , and KH 2 PO 4 were found to have a significant effect on SB degradation bioprocess; they were then further considered for model development using CCD through RSM. A three-factor, five-level CCD with 20 runs was employed ( Safa et al, 2017 ). The variables NH 4 Cl, MgSO 4 , and KH 2 PO 4 were denoted as factors 1, 2, and 3, respectively, and each of them were assessed at five different levels, combining factorial points (−1, + 1), axial points (− α , + α ), and central point (0).…”

Sustainable Approach to Eradicate the Inhibitory Effect of Free-Cyanide on Simultaneous Nitrification and Aerobic Denitrification during Wastewater Treatment

“…FCN is a toxic carbon-nitrogen radical found in various inorganic and organic compounds, some of which are used on an industrial scale. A common form of FCN is hydrogen cyanide (HCN), which can be an odorless gas characterized by a faint, bitter, almond-like odor [61,62]. Cyanide can be found in different forms depending on the pH; at high pH, it is found as an ion of FCN and evaporates as HCN at neutral pH, pKa 9.2.…”