Abstract

PET is a highly versatile material, which is commonly used in water bottle and food-related packaging production. However, PET is also a pollutant in the environment. This project explores hydrolysis methods using environmentally-safe substances, such as ethylene glycol and hydrotalcite, to degrade PET into its intermediate product (MHET). Promising result is shown in further degradation of MHET using fungal treatments to produce terephthalic acid, which is non-toxic to the environment.

Introduction

Polyethylene Terephthalate (PET)

In nature, PET is only degraded by approximately 5-10 µm per year. To compare, the human hair is around 70 µm. A single-use plastic bag takes around 1,000 years to decompose into microplastics that continue to release toxins and pollute the environment[2].

PETase & MHETase

Enzymes that have the ability to break down PET and MHET are called PETase and MHETase, respectively[3]. So far, PETase has been found in many microorganisms, such as fungi and bacteria[4-7]. However, MHETase has only been discovered in a bacteria called Idionella sakaiensis. This bacteria uses PET as its carbon and energy source and produce TPA and ethylene glycol as its final products[8]. In this work, we have discovered a fungi that potentially produces MHETase.

Experimental Procedure

Synthesis of hydrotalcite catalyst:

1. Mg(OH)2 and Al2O3 were suspended in distilled water

2. pH of the solution was charged to 9-10 using NaHCO3

3. Solution was refluxed at 80C for 3hours

4. Resulting white product after filtered and oven-dried

Then, PET was hydrolized with ethylene glycol and hydrotalcite at 198C in a reflux system.

Fungi culture using MHET-fused media to see the potential fungal activity.