BIODEGRADATION OF POLYAMIDES

Naturally occurring homopolyamides are linear poly(amino acids) consis ting either of glutamic acid (poly[gamma glutamic acid], gamma-PGA), l ysine (poly[epsilon lysine]) or arginylaspartic acid (poly[alpha argin ylaspartic acid], cyanophycin). gamma-PGA is synthesized as the major component of capsules and slimes of several Gram-positive bacteria. Pu rified gamma-PGA produced by Bacillus licheniformis ATCC9945 is a high molecular weight, water-soluble white powder leading to highly viscou s solutions at low concentrations, and is resistant to proteolytic att ack. While the synthesis of gamma-PGA has been investigated since its discovery in 1937, not much work has been done on the biodegradation o f the polymer. A screening for gamma-PGA-degrading microorganisms led to the identification and characterization of 12 bacteria species. In this paper, the results of physiological and biochemical investigation s concerning the degradation of poly(gamma glutamic acid) are presente d. (C) 1998 Elsevier Science Limited. All rights reserved.