Page 33 - Abstract book - TJSSF-2020

Thailand – Japan Student Science Fair 2020 (TJ-SSF 2020)
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Micro-plastic Degradation by Bacteria from Intestines of Mealworms

Chayaphol Laotaweerungreung , Pasit Soongying , Parin Jatesiktat
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Advisor: Nattapon Klinput
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Princess Chulabhorn Science High School Phetchaburi
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Abstract
Seventy years ago, plastic waste has increased more than 200 times of each year. Improper disposal of
plastic waste has caused micro-plastics to spread in the environment and to harm ecosystems. The
project aimed to study the micro-plastic degradation by bacteria in intestinal mealworm, and to store
bacteria in moving bed biofilm reactor (MBBR) for decomposition of the micro-plastics. Mealworms
are fed by polyurethane foam (Polystyrene, PS) for fourteen days. Incubated intestines’ mealworms by
using Liquid carbon-free basal medium (LCFBM) and PS film at 24 C, then shook for fourteen days in
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order to get PS degradable bacteria. Cultured bacteria with the agar medium to observe the colonies.
After that, incubated with MBBR at 24 C and shook for 7 days. Finally, froze dry so that it can be
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stored for a long time. In order to examine the stored bacteria could decompose PS, the moving bed
with stored bacteria for 7 days have been tested for PS film decomposition. The results showed that the
average values of contact angle and surface tension in PS film of experimental group and control group
were decreased by 4.33 and 0.2 degrees, respectively. This result indicated that the bacteria in the
intestinal tract of mealworms could decompose Ps film even after being freezing dry and long-term
storage in the MBBR at -20 C for seven days. This study could be used to decompose micro-plastics in
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water source that could not directly eliminated by mealworms

Keywords: Bacteria, Mealworms, Contract angle, Micro-plastic

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