Effect of Carbonic Anhydrase Immobilized on Eggshell Membranes on Calcium Carbonate Crystallization In Vitro

Abstract

The eggshell membranes (ESM) serve as the first interface with the inorganic phase during eggshell formation. During mineral growth, crystals nucleate on the outer side of the ESM at specialized sites called mammillae, mainly consisting of mammillan, a keratan sulfate proteoglycan together with the activity of carbonic anhydrase (CA). In order to get insight into the mechanisms of chicken eggshell mineralization, ESM was used as a biotemplate for immobilizing carbonic anhydrase (CA) and study in vitro calcite crystallization. Here, we showed that when the eggshell membrane supplemented with immobilized or dissolved carbonic anhydrase is located at the gas-liquid interface, calcite nucleation and growth are sequestered by the ESM scaffold from solution, thus affecting the morphology and size of the crystals formed.