Lipase-catalyzed transformation of poly(lactic acid) into cyclic oligomers.
Enzymatic transformations into cyclic oligomers were carried out with the objective of developing chemical recycling of poly(lactic acid)s, such as poly(D,L-lactic acid) (PDLLA), poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA), which are typical biodegradable polymers. They were degraded by lipase in an organic solvent to produce the corresponding cyclic oligomer with a molecular weight of several hundreds. PDLLA (with a Mw of 84,000) was quantitatively transformed into cyclic oligomers by lipase RM (Lipozyme RM IM) in chloroform/hexane at 60 degrees C. PLLA (with a Mw of 120,000) was transformed into cyclic oligomer by lipase CA (Novozym 435) at a higher temperature of 100 degrees C in o-xylene. The oligomer structure was identified by 1H and 13C NMR spectroscopy and MALDI-TOF (matrix assisted laser desorption/ionization-time-of-flight) mass spectrometry.
Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Yosuke
Y
Takahashi
Sachiko
S
Okajima
Kazunobu
K
Toshima
Shuichi
S
Matsumura
D001711:Biotransformation; D003500:Cyclization; D004800:Enzymes, Immobilized / Q000737:chemistry; D005656:Fungal Proteins; D019344:Lactic Acid / Q000737:chemistry / Q000378:metabolism*; D008049:Lipase / Q000737:chemistry*; D011091:Polyesters; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*
D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide); C093667:Novozyme 435; D008049:Lipase