Microbial synthesis of poly(epsilon-lysine) and its various applications.

This review article deals with the microbial synthesis, physiochemical properties, and potential applications of poly-epsilon-lysine (epsilon-PL), which is a naturally occurring biomaterial that is water soluble, biodegradable, edible and non-toxic toward humans and the environment. The potential applications of epsilon-PL as food preservatives, emulsifying agent, dietary agent, biodegradable fibers, highly water absorbable hydrogels, drug carriers, anticancer agent enhancer, biochip coatings in the fields of food, medicine, agriculture and electronics are also discussed in this review.

Antifreeze activities of poly(gamma-glutamic acid) produced by Bacillus licheniformis.

Various enantiomeric isomers, metals salts and molecular sizes of poly(gamma-glutamic acid), gamma-PGA, produced by Bacillus licheniformis CCRC 12826, were prepared and their antifreeze activities were studied by differential scanning calorimetry. The antifreeze activity of gamma-PGA increased as its molecular weight decreased but was indifferent to its D/L-glutamate composition. The antifreeze activity was cation dependent decreasing in the order Mg2+ >> Ca2+ approximately Na+ >> K+ which follows that of inorganic chlorides in that high ionic charge leads to high antifreeze activity.