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ENS04I




               BIODEGRADATION OF POLYETHYLENE BY BACILLUS SUBTILIS
               IN ANAEROBIC CONDITION AND EXTRACT ENZYME FROM
               BACILLUS SUBTILIS


               Kanthamart Khlaikun, Natnicha Sukploy, Nicharee Wangpolpattanasiri
               Kamnoetvidya Science Academy, Thailand
               Supervisor: Janjira Maneesan
               Email: 5900024@kvis.ac.th


               Nowadays, there are a lot of problems about plastic trash, so there are many ways to
               destroy plastic such as landfilling, recycle, and incineration etc. Those ways have many
               disadvantages; the disadvantage of landfilling is that it used very long time to degrade,
               for incineration, if the heat is not enough, the toxic gases will occur which cause air
               pollution.  However,  there  is  one  way  to  destroy  plastic  called  biodegradation.
               Biodegradation  is  the  process  by  which  organic  substances  are  decomposed  by
               microorganisms.  Microorganisms  will  use  carbon  source  from  plastic.  In  anaerobic
               condition, the products are methane, carbon dioxide, and water. Methane can be used
               as fuel or else. Bacillus subtilis is chosen to degrade polyethylene which is the one of
               plastic trash that can found in our daily life. Polyethylene degradation was occurred in
               anaerobic condition in 32 degree celsius on shaker 90-120 revolutions per minute. We
               collected  the  data  every  7  days  by  monitoring  the  surface  of  HDPE  after  the
               degradation via using scanning electron microscope (SEM). Comparing to the surface
               of polyethylene before degrading and the negative control, the result shows that the
               surface of HDPE degraded 14 days in nutrient broth pH 7.0 with  Bacillus subtilis has
               some  shallow  hole.  Moreover,  the  surfaces  of  polyethylene  that  was  degraded  by
               extracted protein from bacteria for 17 days show some change after using SEM.

               Keywords: Biodegradation, Polyethylene, Anaerobic condition
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