Comparison of the Biodegradation of Polyethylene Terephthalate (PET) Plastic Strips between Actinomycetes from Garbage Soil and Mangrove Sediment

Abstract

INTRODUCTION

The Philippines is currently ranked as the world's third biggest contributor to plastic pollution (GreenPeace Philippines, 2017). This increasing rate of plastic pollution is alarmingly affecting not only the environment but also lives. Despite government efforts, the problem still fails to dissipate and the rate of biodegradation cannot catch up to the increasing numbers of plastics. With the potential of utilizing microorganisms in the degradation of plastic waste still left unexplored in the Philippines, this study tested the effectiveness of terrestrial and marine actinomycetes isolated from garbage soil and mangrove sediment, respectively, in degrading polyethylene terephthalate (PET) plastic strips.

METHODS

This study included the collection of soil samples, preparation of Starch Casein Agar (SCA), isolation of actinomycetes, gram staining, and treatment of PET strips using nutrient broth and actinomycetes for ten days. There were three trials and three replicates. The data was gathered by measuring the weight before and after the treatment of plastic and solving for the weight loss percentage. The experimentation was conducted at the Biology Laboratory of Adamson University in Ermita, Manila under the supervision of Ms. Aza Freya Lan Tubato.

RESULTS

The paired sample t-test shows that the final weights of the PET bottle strips are significantly different from its initial weights regardless of the actinomycetes source, as evidenced by a p-value less than 0.05. However, the comparison of the initial and final weight of the PET bottle strips as grouped by actinomycetes source shows that the terrestrial actinomycetes are more effective. The terrestrial actinomycetes had an average of 48% weight loss percentage after ten days of treatment, while the marine actinomycetes only had an average of 15% weight loss percentage for the same period.

DISCUSSIONS

The results showed a significant difference in weight loss, meaning the utilization of microorganisms in degradation is effective. This would be of great help so the environment can slowly recuperate to its original state. Unfortunately, it would be difficult to cultivate and locate the same bacteria. With this, it is suggested that there would be further research involving different bacteria or a different location to get the sample from, as well as using a different type of plastic for degrading.