WHOLE CELL BIOCATALYST PENDEGRADASI PLASTIK SECARA TERMOFILIK DENGAN SISTEM MULTIPLASMID TUF-CUTINASE

• Main Author: Farhan Maulana, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/37011
• Institution: Institut Teknologi Bandung

With global production of up to 140 million tons per year, plastics made from PE polymer (polyethylene) poses an increasing ecological threat. The approach to biodegradation of plastic using microorganisms continues to be developed, such as the whole-cell biocatalyst (WCB). Whole-cell biocatalyst is an approach that makes microorganism cells take a role as catalytic agents like enzymes, therefore no cell lysis or enzyme purification is needed. One of the biodegradation enzymes that has been developed through the WCB principle is LC-Cutinase — an esterase which can degrades polyethylene terephthalate (PET) plastic — which is known to have optimum activity at 55°C and pH 8.0. However, because the cells commonly used for WCB are not thermophilic microorganisms, the WCB viability is thought to be reduced at its enzyme’s optimum temperature — which leads to a decrease in degradation activity. This study aims to determine: does increasing WCB viability on thermophilic condition could also increase substrate degradation activity? Increased viability is carried out by co-transformation of Escherichia coli BL21 (DE3) with plasmids containing the Ef-Tu gene from sugar cane (Saccharum officinarum) and plasmids containing fused protein LC-Cutinase genes that have been mutated synonymously. Proof of increased viability was carried out using the Total Plate Count (TPC) method, and activity measurements were carried out by pNPB (p-nitro-phenylbutyrate) test. WCB which experienced increased viability (Ef-Tu + LC-Cutinase transformant) was shown to have a higher median degradation activity at 55°C, pH 8.0 using the pNPB test. This performance was observed after 90 minutes incubation at 55°C pH 8.0, even after 72 hours. Thus, it can be concluded that an increase in WCB viability will increase its substrate degradation activity at temperatures of 55°C and pH 8.0.