ISOLATION AND CHARACTERIZATION OF POLYHYDROXYALKANOATE (PHA) FROM MIXED CULTURE PRODUCTION OF LOCAL HALOPHILE BACTERIA STRAINS WITH POME AS CARBON SOURCE

• Main Author: Komariah, Siti
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/72841
• Institution: Institut Teknologi Bandung

Plastic is a material that is difficult to degrade and is included in the B3 (Toxic and Hazardous Materials) category, making it less environmentally friendly. There is an alternative material to plastic, bioplastic, which is easier to degrade and can be produced by local strains of halophilic bacteria. However, bioplastics are still rarely used due to considerations of expensive production costs related to carbon sources and low yields. One type of bioplastic that is widely utilized is polyhydroxyalkanoate (PHA) derivatives, namely polyhydroxybutyrate (PHB) and efforts to increase PHB production can be made through the use of mixed cultures of bacteria. Local halophilic bacteria strains, Halomonas elongata BK- AG25 and Salinivibrio sp. are able to produce PHB from POME because the POME content can be converted by three key enzymes involved in the PHB biosynthesis pathway in bacteria. Therefore, the objectives of this study were to determine the synergistic effect of mixing the two bacteria on increasing the yield of PHB production using palm oil mill effluent (POME) as a carbon source and to determine the physicochemical properties of PHB obtained. The product was characterized with FT-IR for functional group analysis, thermal properties analysis with TGA/DTG/DTA, and validation of the product structure with 1H-NMR. The results showed that the mixed culture of halophilic bacteria of this local strain had a synergistic effect with a product yield of 200 ± 70.71 mg/L media, higher than the yield in pure culture. The results of product characterization using FT-IR showed the presence of absorption peaks corresponding to the vibrations of functional groups contained in PHB. Product characterization using TGA/DTG/DTA showed a decomposition temperature of 256°C, weight loss of 2.14% per minute, and an exothermic peak at 252°C. These results indicate a difference in physicochemical properties between the product in mixed culture and the product in pure culture. The 1H-NMR spectrum of the product showed the product's compatibility with the polyhydroxybutyrate-valerate (PHBV) type bioplastic structure compared to PHB. This indicates that the production of bioplastics in mixed culture is related to the physicochemical properties of the bioplastics produced.