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 m edium. Inhibitor studies confirm that this COS uptake is catalyzed by the e nzyme carbonic anhydrase, which was not detectable with conventional method s. 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.