Enzymatic consumption of carbonyl sulfide (COS) by marine algae

We show that the marine algae Mantoniella squamata, Prymnesium parvum, and Amphidinium klebsii take up carbonyl sulfide (COS) from their surrounding medium. Inhibitor studies confirm that this COS uptake is catalyzed by the enzyme carbonic anhydrase, which was not detectable with conventional methods. As shown for M. squamata, the COS uptake can be dependent on the growth conditions. Furthermore, COS uptake shows a clear positive correlation with the COS concentration in the growth medium. The value of K-1/2 for the COS uptake was estimated to be around 222 mol/m(3). The COS consumption by the marine algae species investigated was estimated to be negligible compared to the photoproduction and hydrolysis of COS in seawater.