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. The mechanism by which the cryoprotective effects of gamma-PGA can be explained is still yet to be determined.
Shih
Ing-Lung
IL
Department of Environmental Engineering, Da-Yeh University, Chang-Hwa, Taiwan. ils@mail.dyu.edu.tw
Van
Yi-Tsong
YT
Sau
Yi-Yuan
YY
D021301:Antifreeze Proteins / Q000737:chemistry / Q000528:radiation effects; D001407:Bacillus / Q000145:classification / Q000378:metabolism*; D040761:Biomimetic Materials / Q000737:chemistry* / Q000378:metabolism / Q000528:radiation effects*; D003451:Cryoprotective Agents / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D005615:Freezing; D011099:Polyglutamic Acid / Q000096:biosynthesis / Q000737:chemistry* / Q000528:radiation effects*; D013045:Species Specificity; D014867:Water / Q000737:chemistry*
D021301:Antifreeze Proteins; D003451:Cryoprotective Agents; D014867:Water; D011099:Polyglutamic Acid