Plastics, non-biodegradable before, not anymore

May 13, 2009 by OVCRE

Each barangay, town or city in the Philippines has its own story to tell about its waste disposal problems. While some of them lack or have none to guarantee good waste disposal management, the town of Los Baños in Laguna has one to vouch for a cleaner future with the promising results of a research project currently done by the University of the Philippines Los Baños (UPLB).

Dr. Virginia Cuevas of the Institute of Biological Sciences of UPLB and her co-researchers have recently identified Xylaria mutants that can be potentially developed into a product capable of degrading plastic bags usually found in dumpsites. Xylaria is a fungus that grows on dead wood, utilizing the latter’s components such cellulose, hemicelluloses and lignin as food. In 2001, Dr. Cuevas showed evidence of Xylaria colonizing polyethylene (PET) plastic strips. Most plastic bags, including garbage bags, are now made of PET.

The UPLB researchers have been busy in helping the town’s waste processing program by studying fungi that degrade plastic and compost biodegradable materials.

In an experiment at the Los Baños Eco Waste Center, Dr. Cuevas and her team found out that white mutant strains of Xylaria are most effective in degrading plastic wastes. The experiment evaluated wild and mutant strains of Xylaria for their capability in decomposing organic matter and plastic materials.

The project also tested the capability of mixed cultures of Xylaria and Trichoderma for rapid composting of the town’s wastes that included plastics. Also a fungus, Trichoderma is a proven compost activator. Dr. Cuevas, in fact, has already developed a rapid composting technology using Trichoderma.

According to the project’s results, composting using the mixed cultures took only 30-35 days. After 35 days, the compost is ready for use. Ripe compost produced by the project did not harbor harmful E. coli and Salmonella and did not contain heavy metals such as copper, arsenic, cadmium and mercury.

A field trial using the compost for Baby’s Breath (Aster) production is now ongoing. Field trials will also be done on rice, corn and other vegetables starting May this year.