Jarerat Amnat, Tokiwa Yutaka, Tanaka Hideo
CPR Co., Ltd., 4-102, Higashinobusue, Himeji, Hyogo, 670-0965, Japan.
Appl Microbiol Biotechnol. 2006 Oct;72(4):726-31. doi: 10.1007/s00253-006-0343-4. Epub 2006 Feb 14.
Efficient production of poly(L-lactide)(PLA)-degrading enzyme was achieved by addition of 0.1% (w/v) silk fibroin powder into a liquid culture medium of an actinomycete, Amycolatopsis orientalis, without other complex nitrogen sources, such as yeast extract and peptone. Scaled-up production of the enzyme in a 5-l jar fermenter showed the possibility of producing this enzyme on an industrial scale at low production cost. The extracellular PLA-degrading enzyme showed potent degrading activity, which is effective for biological recycling of PLA, i.e., 2,000 mg/l of PLA powder was completely degraded within 8 h at 40 degrees C using 20 mg/l purified enzyme. An optically active L-lactic acid with 600 mg/l was obtained as degradation product of PLA without undesirable racemization.
通过向东方拟无枝酸菌的液体培养基中添加0.1%（w/v）的丝素蛋白粉，在不添加酵母提取物和蛋白胨等其他复杂氮源的情况下，高效生产了聚（L-丙交酯）（PLA）降解酶。在5升罐式发酵罐中扩大该酶的生产规模，显示了以低成本在工业规模上生产这种酶的可能性。细胞外PLA降解酶表现出强大的降解活性，这对PLA的生物循环有效，即使用20mg/l的纯化酶，在40℃下，2000mg/l的PLA粉末在8小时内完全降解。得到了600mg/l的旋光性L-乳酸，作为PLA的降解产物，且没有不希望的外消旋化。
