Abstract
Plastic wastes and their persistence in the environment impose prominent problems around the globe. Among different types of plastics, synthetic ones such as polyethylene terephthalate (PET) are more difficult to degrade. This is due to the high ratio of aromatic terephthalate units in the PET structure. Amongst different approaches for the degradation of plastics, biodegradation is considered increasingly as a preferred method due to it being environmentally friendly. However, the biodegradation efficiency is not high. One of the reasons for this is that the temperature required for bacterial growth is much less than the glass transition temperature of PET. To overcome the shortcoming, complementary techniques have been suggested to enhance biodegradation. Amongst the techniques, pre-treatment of PET has shown promise. To this effect, physical (e.g., use of UV radiation), chemical (e.g., alkaline treatment) and biochemical methods (use of surfactants) have been adopted with varying success. This paper reports the effects of two surfactants, a cationic surfactant dodecyl trimethylammonium bromide (DTAB), and a non-ionic surfactant Dodecyl polyethylene oxide-23 ether (Brij-35) for pre-treat the PET. Two techniques were used to study the outcome of the aforementioned treatments on PET and its biodegradation: FTIR and biofilm assay. DTAB treatment in the presence of the bacterial culture Ideonella sakaiensis (I. sakaiensis) in Yeast Extract-Sodium Carbonate and Vitamins (YSV) medium depicted notable potential for enhancement of the degradation of PET. This was verified by changes in PET carbonyl groups. So, it is possible that other mechanisms could be involved in addition to the already suggested alteration in electrical charges.
