Kitamoto Hiroko, Yoshida Shigenobu, Koitabashi Motoo, Yamamoto-Tamura Kimiko, Ueda Hirokazu, Yarimizu Tohru, Sameshima-Yamashita Yuka
National Agricultural Food Research Organization (NARO), 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan.
National Agricultural Food Research Organization (NARO), 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan.
J Biosci Bioeng. 2018 Feb;125(2):199-204. doi: 10.1016/j.jbiosc.2017.08.017. Epub 2017 Sep 23.
Agricultural mulch films made from biodegradable polymers (BP) have been used to decrease the burden of plastic waste recovery and recycling. However, their degradations depend largely on environmental conditions and sometimes do not proceed as desired. Yeast strains of Pseudozyma antarctica often isolated from rice husks were found to secrete an esterase to degrade BP films. Poly-butylene succinate-co-adipate (PBSA) films buried in unsterilized rice husks with 60% (w/w) moisture degraded rapidly compared to that buried in field soil. The type strain of P. antarctica JCM 10317 added as cell suspension onto sterilized rice husks with PBSA film grew rapidly forming filamentous growth on the surface of rice husks and films. BP-degrading enzyme secreted by the growing cells was adsorbed on the surface of film and decomposed the film. Addition of rice husk-derived P. antarctica strains also showed BP film degradation activity in sterilized rice husks. In the light of these findings, we suggest that techniques for disposal of used BPs which combine plastics with unutilized residual plant materials piled at the side of agricultural fields be developed.
由可生物降解聚合物（BP）制成的农用薄膜已被用于减轻塑料废物回收和再利用的负担。然而，它们的降解很大程度上取决于环境条件，有时并不能如预期那样进行。经常从稻壳中分离出的南极假丝酵母菌株被发现能分泌一种酯酶来降解BP薄膜。与埋在田间土壤中的聚丁二酸丁二醇酯-共-己二酸酯（PBSA）薄膜相比，埋在含水量为60%（w/w）的未灭菌稻壳中的PBSA薄膜降解迅速。作为细胞悬浮液添加到带有PBSA薄膜的灭菌稻壳上的南极假丝酵母模式菌株JCM 10317生长迅速，在稻壳和薄膜表面形成丝状生长。生长的细胞分泌的BP降解酶吸附在薄膜表面并分解薄膜。添加源自稻壳的南极假丝酵母菌株也在灭菌稻壳中表现出BP薄膜降解活性。鉴于这些发现，我们建议开发将塑料与堆放在农田边的未利用残余植物材料相结合的废旧BP处置技术。
