The respiratory responses to cyanide of a cyanide-resistant Klebsiella oxytoca bacterial strain

Abstract

The respiratory system of a cyanide-resistant Klebsiella oxytoca was analyzed by monitoring the changes in the cytochrome contents in response to various inhibitors in the presence of various concentrations of cyanide. The cells grown in the medium without cyanide (KCN) have two terminal oxidases, cytochrome d (K i = 10 3S M KCN) and o (K i = 10 3Q M KCN). When cells were grown on medium with 1 mM KCN, the expression of both b-type cytochrome and cytochrome d in the plasma membranes of the cell decreased by more than 50%, while cytochrome o increased by 70%, as compared with the cells grown in the absence of KCN. Two terminal oxidases with K i values of about 10 3Q M and 1.7U10 3P M KCN were observed in the plasma membrane fractions of the cells growing on KCN enriched medium. 2-n-Heptyl-4-hydroxyquinoline-N-oxide markedly inhibited the oxidation of NADH by the plasma membranes from the cells grown in the medium without KCN, but not in those plasma membranes from KCN-grown cells. The NADH oxidases in plasma membranes of K. oxytoca grown with and without KCN were equally sensitive to UV irradiation. Adding freshly isolated quinone to the UV-damaged plasma membranes restored the NADH oxidase activity from both types of plasma membranes. From these results, we propose the presence of a non-heme type of terminal oxidase to account for the KCN resistance in K. oxytoca. z

Cyanide removal from cassava mill wastewater using Azotobactor vinelandii TISTR 1094 with mixed microorganisms in activated sludge treatment system

“…cytochrome oxidase required for cells to respire aerobically [3]. Ingesting cyanide can also result in either acute poisoning (including death) or chronic poisoning to humans and animals.…”

“…Several researchers report that biological processes could be used to remove cyanide compounds from wastewater [8][9][10]. Some organisms resistant to cyanide have been reported to remain active even at concentrations higher than 1 mM of cyanide [3]. Bacillus, Pseudomonas, and Klebsiella oxytoca have been reported to biodegrade cyanide to non-toxic end-products and using cyanide as the sole nitrogen source under aerobic and/or anaerobic environment [10][11][12].…”

Degradation of soil cyanide by single and mixed cultures of Pseudomonas stutzeri and Bacillus subtilis

“…Natural soil microflora have been demonstrated to convert cyanide to carbonate and ammonia (7). Some organisms resistant to cyanide have been reported to remain active even at concentrations higher than 1 mmol L -1 (8).…”

Statistical Enhancement of Cyanide Degradation Using Microbial Consortium

“…CN-22 was isolated from a cyanide-contaminated electroplating sludge and found to be able to tolerate a CN − concentration of 700 mg l −1 [7]. Klebsiella oxytoca can remain active at a CN − concentration of 26mg l −1 [21] and the immobilized cells of K. oxytoca could tolerate a higher CN − concentration of 78 mg l −1 [18]. Azotobacter vinelandii has CN − resistance at 104 mg l −1 [22], and Serratia marcescens RL2b could tolerate 780 mg l -1 of potassium cyanide [10] which is the highest concentration of cyanide tolerated by microorganisms reported so far.…”