Immobilization of Photosynthetic Membranes in an Albumin-Glutaraldehyde Crosslinked Matrix

Abstract

The photosynthetic membranes of chloroplasts are responsible for capturing light energy and converting it into chemical intermediates. During this process, negatively charged species are formed and water molecules are cleaved. These properties confer to thylakoid membranes a great potential for various biotechnological applications. However, the isolated membranes have a relatively short active life time that limits their effective use. To circumvent this limitation, various immobilization techniques have been designed to improve the stability of biological functions. Isolated chloroplasts or thylakoid membranes have been immobilized using various procedures, but immobilization in an albumin-glutaraldehyde crosslinked matrix provides a better preservation of the native thylakoid activity and maintains a greater functional stability when compared to immobilization by several other techniques (1,2). This immobilization method provides good protection against aging and strong illumination (3–5). It can be used not only in whole thylakoid membranes (6) but also in submembrane fractions enriched in photosystem I or photosystem II (7,8). In this chapter, methods are described to obtain membrane preparations of either whole thylakoid membranes (9) or isolated submembrane fractions (10,11), followed by their immobilization in an albumin-glutaraldehyde crosslinked support. The storage properties of the immobilized material are also mentioned since these are essential for the proper use of immobilized photosynthetic membranes.