PLLA-degrading activity was measured in a reaction mixture
composed of 5 mg of PLLA powder, 2.0 ml of 0.1 m phosphate
buffer (pH 7.0), 0.05 ml of 0.5% (wt/vol) octyl glucopyranoside
and 0.5 ml of enzyme solution. The mixture was
shaken at 100 times/min at 378C for 12 h. l-Lactic acid
formed during the reaction was enzymatically analyzed with
an l-lactic acid analysis kit (Roche Diagnostic Co.). One
unit (U) of PLLA-degrading activity was defined as the
amount of enzyme required to produce 1 lmol of L-lactic
acid in 1 min.