A novel strategy for the efficient removal of toxic cyanate by the combinatorial use of recombinant enzymes immobilized on aminosilane modified magnetic nanoparticles.

Cyanase detoxifies cyanate by transforming it to ammonia and carbon dioxide in a bicarbonate-dependent reaction, however, dependence on bicarbonate limits its utilization in large-scale applications. A novel strategy was therefore developed for overcoming this bottleneck by the combined application of cyanase (rTl-Cyn) and carbonic anhydrase (rTl-CA). The synergistic effect of rTl-Cyn and rTl-CA could reduce the dependence of bicarbonate by 80%, compared to using rTl-Cyn alone. Complete degradation of cyanate (4 mM) was achieved with buffered conditions and 85 ± 5% degradation with industrial wastewater sample, when 20 U of rTl-Cyn was applied. Furthermore, a similar percentage of degradation was achieved using 80% less bicarbonate, when rTl-Cyn and rTl-CA were used together under identical conditions. In addition, rTl-Cyn and rTl-CA were immobilized onto the magnetic nanoparticles and their catalytic activity, stability and reusability were also evaluated. This is the first report on the synergistic biocatalysis by rTl-Cyn and rTl-CA, for cyanate detoxification.