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Updated: Jan 28, 2026

Aerobic Biodegradation Testing of Materials Using a Natural Marine Seawater Inoculum and Closed Loop Respirometer
Published on: October 24, 2025
Extracellular carbonic anhydrase: Method development and its application to natural seawater
Nur Ili Hamizah Mustaffa1, Maren Striebel1, Oliver Wurl1
1Institute for Chemistry and Biology of the Marine Environment, Carl Von Ossietzky Universität Oldenburg Wilhelmshaven Germany.
Abstract:
We developed an effective fluorometric technique to quantify extracellular carbonic anhydrase (eCA) present in natural seawater samples. The technique includes the separation of eCA from cells to achieve low detection limits through high signal : noise ratios. eCA was efficiently extracted from cell membranes by treatment with 0.1 M phosphate buffer containing 2.5 M NaCl. The free eCA specifically forms a fluorescent complex with dansylamide, and the detection limit of the complex is below 0.1 nM. We applied the technique to samples from different culture solutions and natural seawater collected from the Baltic Sea. We observed eCA concentrations to be in the range of 0.10-0.67 nM in natural seawater. The data indicated that this technique is very sensitive, accurate, and feasible for routine and shipboard measurement of eCA from natural seawater. It is therefore an effective and rapid tool to investigate the carbon acquisition of phytoplankton both in mono culture as well natural communities.
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