Isolation of bacteria strains capable to degradate poly (lactic acid)

  • Nguyễn Thị Thanh Lịch
  • Lê Hải Vân
  • Nguyễn Quang Huy

Abstract

Recently, the products of synthetic polymers as plastics have been commonly utilized.However, the facts have shown that due to their extreme resistance to microbial attacks, these products are conducive to the enormous wastes, which lead to put environment in danger. Biopolymers, such as poly hydroxybutyrate (PHB), poly (lactic acid) (PLA), poly (e -caprolactone) (PCL)…, are gradually replacing ordinary plastic in daily activities, which results from their capability to degrade rapidly themselves. PLA is now one of the focuses of world wide attention.

In spite of an active interest in PLA as a biodegradable material, there have been only few studies on its biodegradation, especially on its microbial degradation.

Twelve PLA-degrading bacteria were isolated from wasted soil and water samples by enrichment method. One of them, strain T2 was selected to next research because of its rapid growth in the selective medium added PLA as carbon source and the ability of forming largest clear zone on plate. After 20 days of cultivation, strain T2 degraded more than 79.9 % PLA added in the culture at 37 oC. Biochemistry characterizations showed that strain T2 expressed protease, cellulose and catalase activity and used some kinds of sugar such as sucrose, fructose, glucose…The 16S rRNA gene sequence analysis, strain T2 was similar 99.9 % with 16S rARN of Klebsiella variicola_AJ783916. This strain also degraded more than 39.9 % PCL and 71 % PHB added in the culture after 20 days of cultivation at 37 oC.

điểm /   đánh giá
Published
2014-11-10
Section
Articles