Changes on polystyrene surface and biofilm formation as indication of biodegradation by soil microorganisms

It was reported that an amount of 5.475 million tons of solid waste which was about 0.81 kg per capita per day was estimated to generate in Malaysia [1] while in main cities in Malaysia, the amount increased to 1.7 kg per capita per day [2] in 2001. Solid waste increased due to the used of plastics especially polystyrene in every field of life. However, polystyrene can be degraded through biodegradation. The aim of the study is to observe the changing in polystyrene's surface and also biofilm formed by microorganisms from different soil samples using Electron Scanning Microscope (ESEM). Scanning electron microscopy is a tool to observe cavities and grooves formed on the plastic film, which directly reflected the extent of microbial colonization and degradation [3]. In this study, water filtrate from soil samples obtained from one landfill area, two waste disposal sites and one from soil burial method were collected and incubated with sterilized polystyrene at 30^oC for 8 weeks before observation using ESEM was done. Formation of biofilm and changes in polystyrene's surface; crack, pit/cavity, erosion/rough indicated that the degradation have taken place due to colonization and adhered by bacteria on polystyrene which act as sole carbon for their survival due to carbon starvation.

[1] Ngoc, U and H. Schnitzer. “Sustainable solutions for solid waste management in Southeast Asian countries.” Waste Management 2009, 29:1982 – 1995.

[2] Kathirvale S. Comprehensive Characteristics of the Municipal Solid Waste Generated In Kuala Lumpur. Engineering Faculty, University Kebangsaan Malaysia and Technical Services Division, Malaysian Institute for Nuclear Technology Research. 2003.

[3] Sekhar V. C, Nampoothiri K. M, Mohan A. J, Nair N. R. Journal of Hazardous Materials. 2016, 347 – 354.