Immobilization of E. coli expressing Bacillus pumilus CynD in three organic polymer matrices

Carmona-Orozco, María L.; Panay, Aram J.

doi:10.1007/s00253-019-09859-z

Cited by 7 publications

(8 citation statements)

References 35 publications

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“…The use of permeabilized cells, however, is undesirable due to the need to use organic solvents to produce them. Therefore, bioreactors utilizing immobilized E. coli-CynD on solid supports (Carmona & Panay, 2019) should be explored for the bioremediation of industrial cyanide wastes.…”

Section: E Coli-cynd Viability In Gold Mining Cyanide Wastewatersmentioning

confidence: 99%

Biodegradation of cyanide using recombinant Escherichia coli expressing Bacillus pumilus cyanide dihydratase

Panay

Vargas-Serna

Carmona-Orozco

2020

Rev. colomb. biotecnol.

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Despite its high toxicity, cyanide is used in several industrial processes, and as a result, large volumes of cyanide wastewater need to be treated prior to discharge. Enzymatic degradation of industrial cyanide wastewater by cyanide dihydratase, which is capable of converting cyanide to ammonia and formate, is an attractive alternative to conventional chemical methods of cyanide decontamination. However, the main impediment to the use of this enzyme for the biodegradation of cyanide is the intolerance to the alkaline pH at which cyanide waste is kept and its low thermoresistance. In the present study, the catalytic properties of whole E. coli cells overexpressing a cyanide dihydratase gene from B. pumilus were compared to those of the purified enzyme under conditions similar to those found in industrial cyanide wastewater. In addition, the capacity of whole cells to degrade free cyanide in contaminated wastewater resulting from the gold mining process was also determined. The characteristics of intracellular enzyme, relative to purified enzyme, included increased thermostability, as well as greater tolerance to heavy metals and to a lesser extent pH. On the other hand, significant enzymatic degradation (70%) of free cyanide in the industrial sample was achieved only after dilution. Nevertheless, the increased thermostability observed for intracellular CynD suggest that whole cells of E. coli overexpressing CynD are suited for process that operate at elevated temperatures, a limitation observed for the purified enzyme.

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Section: E Coli-cynd Viability In Gold Mining Cyanide Wastewatersmentioning

confidence: 99%

Biodegradation of cyanide using recombinant Escherichia coli expressing Bacillus pumilus cyanide dihydratase

Panay

Vargas-Serna

Carmona-Orozco

2020

Rev. colomb. biotecnol.

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“…Another one contained about 30 mM Cu, 83 mM Ni and 0.9 mM Zn [37]. The fCN concentrations in these effluents can be extremely high (approximately 0.5-2 M) [2,3,37]. The CynD was not sufficiently effective in the original gold-mine effluent (528 mM fCN) and only removed 43% of the fCN [2].…”

Section: Enzyme Performance In the Presence Of Heavy Metal Saltsmentioning

confidence: 99%

“…The fCN concentrations in these effluents can be extremely high (approximately 0.5-2 M) [2,3,37]. The CynD was not sufficiently effective in the original gold-mine effluent (528 mM fCN) and only removed 43% of the fCN [2]. Therefore, it was necessary to dilute this solution to 17.6 mM fCN [2] before applying the enzyme.…”

Section: Enzyme Performance In the Presence Of Heavy Metal Saltsmentioning

confidence: 99%

“…For example, it is used to leach gold and silver from their ores. These processes generate significant amounts of cyanide waste [1,2]. Cyanide wastewaters also come from, e.g., electroplating, jewelry industry, (petro)chemical industry and cokemaking [1,[3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…Another CynH was used with a spiked cokemaking effluent and degraded, e.g., 10 mM fCN to almost 100% [4]. In addition, an immobilized whole-cell CynD biocatalyst was used with diluted gold-mine wastewater and the maximum conversion was 98% starting from 17.6 mM fCN [2].…”

Section: Introductionmentioning

confidence: 99%

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Application Potential of Cyanide Hydratase from Exidia glandulosa: Free Cyanide Removal from Simulated Industrial Effluents

et al. 2021

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Industries such as mining, cokemaking, (petro)chemical and electroplating produce effluents that contain free cyanide (fCN = HCN + CN−). Currently, fCN is mainly removed by (physico)chemical methods or by biotreatment with activated sludge. Cyanide hydratases (CynHs) (EC 4.2.1.66), which convert fCN to the much less toxic formamide, have been considered for a mild approach to wastewater decyanation. However, few data are available to evaluate the application potential of CynHs. In this study, we used a new CynH from Exidia glandulosa (protein KZV92691.1 designated NitEg by us), which was overproduced in Escherichia coli. The purified NitEg was highly active for fCN with 784 U/mg protein, kcat 927/s and kcat/KM 42/s/mM. It exhibited optimal activities at pH approximately 6–9 and 40–45 °C. It was quite stable in this pH range, and retained approximately 40% activity at 37 °C after 1 day. Silver and copper ions (1 mM) decreased its activity by 30–40%. The removal of 98–100% fCN was achieved for 0.6–100 mM fCN. Moreover, thiocyanate, sulfide, ammonia or phenol added in amounts typical of industrial effluents did not significantly reduce the fCN conversion, while electroplating effluents may need to be diluted due to high fCN and metal content. The ease of preparation of NitEg, its high specific activity, robustness and long shelf life make it a promising biocatalyst for the detoxification of fCN.

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A critical review for advances on industrialization of immobilized cell Bioreactors: Economic evaluation on cellulose hydrolysis for PHB production

Boura

Dima

Nigam

et al. 2022

Bioresource Technology

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Immobilization of E. coli expressing Bacillus pumilus CynD in three organic polymer matrices

Cited by 7 publications

References 35 publications

Biodegradation of cyanide using recombinant Escherichia coli expressing Bacillus pumilus cyanide dihydratase

Biodegradation of cyanide using recombinant Escherichia coli expressing Bacillus pumilus cyanide dihydratase

Application Potential of Cyanide Hydratase from Exidia glandulosa: Free Cyanide Removal from Simulated Industrial Effluents

A critical review for advances on industrialization of immobilized cell Bioreactors: Economic evaluation on cellulose hydrolysis for PHB production

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