A green and low-cost removal method for cyanate, a toxic byproduct from the treatment of cyanide, is still needed. Cyanase converts cyanate to CO
2 and NH
3, but its industrial practicality is limited because the reaction requires HCO
3− as
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A green and low-cost removal method for cyanate, a toxic byproduct from the treatment of cyanide, is still needed. Cyanase converts cyanate to CO
2 and NH
3, but its industrial practicality is limited because the reaction requires HCO
3− as a substrate. In this study, we used carbonic anhydrase from
Sulfurihydrogenibium azorense (SazCA) to provide HCO
3− for cyanase from
Thermomyces lanuginosus (TlCyn); both TlCyn and SazCA were purified by one-step heating without prior cell lysis. The heat treatment resulted in higher activities of both enzymes than the conventional two-step process. From a 50 mL-culture, the highest total activity of 147 U and 47,174 WAU was obtained from 5 min of heating at 60 and 80 °C for TlCyn and SazCA, respectively. The coupled enzymatic system was used to degrade cyanate in three different matrices: 50 mM Tris-HCl (pH 8), industrial wastewater, and artificial wastewater. In the industrial wastewater, with the addition of 0.75 WAU (Wilbur-Anderson unit) of SazCA, cyanate degradation using 0.5 mM NaHCO
3 was similar to that using 3 mM NaHCO
3, indicating an 83% reduction in NaHCO
3. We have demonstrated that the dependence on HCO
3− of cyanate degradation can be effectively alleviated by using low-cost heat-purified TlCyn and SazCA; the industrial practicality of the coupled enzymatic system is therefore improved.
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