No abstract

The polylactic acid (PLA) is a polymer of plant origin, which having biodegradability for various usages as an environmentally friendly greening materials. PLA is used as a material for the sand bag and the mulching seat in the construction business. However, it is known that the bio-degradable speed of PLA is very slow, and only a few microorganisms can biodegrade it. Thus, the method to decompose PLA cloth in the bark compost was examined by using urea, and the following results were obtained: 1) PLA cloth in the bark compost was degraded by ammonia that was generated by hydrolysis of the additive urea 2) The formula to predict decomposition rates of PLA cloths in ammonia aqueous solutions could be applied for that in the bark compost. 3) The microbial growth in the bark compost was observed when the added amount of urea was less than 5 wt%, however, the alkalinization of the bark compost, which would affect the microbial environment, occurred at the higher urea concentration.