Biodegradable mulch film has been commercially available for about 20 years. Hiroko Kitamoto and her team from theNational Institute of Agro-Environmental Sciences had discovered that Pseudozyma Antarctica which is ubiquitous on plant surfaces, break down biodegradable plastics by a secreted esterase PaE .
This degrading enzyme, PaE, was known to degrade polybutylene succinate adipate (PBSA), polybutylene succinate (PBS), and amorphous polylactic acid (PLA), which were used as materials when biodegradable mulch film was first marketed. When the PaE solution was sprayed on the surface of a commercial biodegradable mulch film in a field, the film strength decreased the next day. The day after the solution was applied, the mulch film became thinner and cracked visually and at the microscopic level. After spraying the PaE solution, the mulch film was then plowed into the field, as agricultural producers actually do. The film was then collected and examined, and it was found that the enzyme treatment accelerated the degradation of the film. Compared to mulch film recovered from the untreated area, mulch film recovered from the solution-treated area had fewer large fragments and the total weight of mulch film recovered was less.
The National Agricultural Research Institute is now working to (1) establish a method for mass production of PaE, (2) verify how degradation progresses after biodegradable mulch film sprayed with PaE is buried in a field, (3) develop a new cultivation method combining biodegradable mulch film and PaE, and (4) develop new biodegradable mulch film to be used in combination with PaE. (4) Development of new biodegradable agricultural materials to be used in combination with PaE