Cyanophycin: Biosynthesis and Applications
Ahmed Sallam, Anna Steinle and Alexander Steinbüchel
from: Microbial Production of Biopolymers and Polymer Precursors: Applications and Perspectives (Edited by: Bernd H. A. Rehm). Caister Academic Press, U.K. (2009)
This chapter provides an overview on the synthesis, large-scale production, biodegradation and potential applications of the polyamide cyanophycin (CGP), which is a non-ribosomally synthesized compound consisting of a poly(aspartic acid) backbone with arginine residues linked to the carboxyl group of each aspartate by their amino group. In its natural host microorganisms, CGP functions as a storage polymer for nitrogen, carbon and energy. The key enzyme of CGP synthesis is represented by the CGP synthetase (CphA). The gene coding for this enzyme has been used for recombinant expression of CGP biosynthesis in various prokaryotes. Meanwhile, also transgenic eukaryotes, yeasts and plants, were enabled to synthesize the polymer in considerable amounts. Biodegradation of CGP occurs by intra- or extracellular CGPases, CphB or CphE, respectively. Degradation products of CGP are usually dipeptides which are then split to free amino acids by intracellular dipeptidases. Biotechnical interest of CGP is high; products resulting from its biodegradation could be applied in various biochemical, medical or industrial applications read more ...