The effect of pH-temperature on plastic allowance for Low-Density Polyethylene (LDPE) by Thiobacillus sp. and Clostridium sp.

Abstract

LDPE are plastic polymers, widely used because they are affordable, waterproof, and flexible, hence difficult to degrade naturally. This study aim therefore is to degrade LDPE plastic using a biotechnology approach with a mixture of Thiobacillus sp. and Clostridium sp. at a variety of pH and temperatures. Mixed bacterial cultures were grown on Stone Mineral Salt Solution (SMSs) with a batch system, thereafter, gravimetric method was used to determine the difference in weight and Fourier Transformer Infrared Spectroscopy (FTIR) was used to determine changes in functional groups. To obtain the optimum condition that produces the highest degradation, researchers conducted the experiment at temperature varied from 25, 30, 35o C and pH 5, 7, 9. The highest removal of LDPE occurred at 30oC with pH 7. Gravimetrically, mixed cultures of Thiobacillus sp. and Clostridium sp. was capable of degrading LDPE plastic with an allowance of 2-7% for 30 days. Considering that this research produces a relatively small allowance, further research is needed to exploit the potential of using both bacteria in degrading LDPE plastic.