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"Polyhydroxyalkanoate(PHA) is one of the alternatively biodegradable plastics which can besynthesized from a particular micro-organism after the fermentation process,considering the optimization of nutrients. In this research, the yeaststrain Rhodotorula graminis TISTR 5124 was selected to be fermented with a carbonsource in the standard nutrient in order to conduct a preliminarily study on thebest conditions for thisyeast in PHA production. The growth rate curve of yeast in the composition of imbalancednutrients, i.e. the limitationof phosphorus and nitrogen, was also investigated and compared with another sample cultured in standard nutrients. Experimental results indicated that thecondition that gave the maximum growth rate of this yeast strain was aP-limited condition at 81 hours, whereby the cell number of 3.1×109cells/mL wasobtained and corresponded to the optical density (OD) of 0.95 measured at awavelength of 600 nm. The synthesized PHA extracted from yeast cells after 81hours of incubation was examined by Fouriertransform infra-red (FT-IR) and nuclear magnetic resonance (1H NMR) spectroscopy. The results indicated stretchingvibrations similar to the copolymer PHBV (or a PHA derivative). Maximum PHA content of 54.4% wasfound in the P-limited condition which correspondedto a PHA yield of 65.1 (g/g-total sugar consumed) in which the yeast consumed the least glucose amount of 3.2 g/L, butgrew the most rapidly. Rhodotorulagraminis TISTR 5124 is therefore promising as a good candidate for alternativelybiodegradable plastics, considering the potential to produce PHA and its derivatives. This process can be beneficial as an option to replace conventional plastics inthe future."

"Polyhydroxyalkanoate (PHA) is one of the alternatively biodegradable plastics which can be synthesized from a particular micro-organism after the fermentation process, considering the optimization of nutrients. In this research, the yeast strain Rhodotorula graminis TISTR 5124 was selected to be fermented with a carbon source in the standard nutrient in order to conduct a preliminarily study on the best conditions for this yeast in PHA production. The growth rate curve of yeast in the composition of imbalanced nutrients, i.e. the limitation of phosphorus and nitrogen, was also investigated and compared with another sample cultured in standard nutrients. Experimental results indicated that the condition that gave the maximum growth rate of this yeast strain was a P-limited condition at 81 hours, whereby the cell number of 3.1×109cells/mL was obtained and corresponded to the optical density (OD) of 0.95 measured at a wavelength of 600 nm. The synthesized PHA extracted from yeast cells after 81 hours of incubation was examined by Fourier transform infra-red (FT-IR) and nuclear magnetic resonance (1H NMR) spectroscopy. The results indicated stretching vibrations similar to the copolymer PHBV (or a PHA derivative). Maximum PHA content of 54.4% was found in the P-limited condition which corresponded to a PHA yield of 65.1 (g/g-total sugar consumed) in which the yeast consumed the least glucose amount of 3.2 g/L, but grew the most rapidly. Rhodotorula graminis TISTR 5124 is therefore promising as a good candidate for alternatively biodegradable plastics, considering the potential to produce PHA and its derivatives. This process can be beneficial as an option to replace conventional plastics in the future."

"ABSTRAKPolusi plastik menjadi masalah lingkungan yang semakin serius dan banyak dorongan dari berbagai pihak untuk memberhentikan pemakaian plastik sekali pakai dan plastik non-biodegradable. Polyhydroxyalkanoate (PHA) adalah termoplastik biodegradable dan bioderived yang menunjukkan potensi besar sebagai pengganti untuk plastik yang selama ini digunakan dalam berbagai aplikasi. Pasar PHA saat ini memiliki pasokan yang terbatas, padahal ini adalah waktu yang tepat untuk memanfaatkan pasar plastik biodegradable dan bioderived yang berkembang ini. Fasilitas manufaktur untuk memproduksi 5000 ton per tahun PHA bioplastik dari jus tebu harus didesain. Berbagai proses pembuatan dievaluasi untuk menentukan proses yang paling cocok untuk aplikasi ini. Kultur murni Ralstonia eutropha adalah bakteri yang direkomendasikan untuk menghasilkan polimer PHA karena menghasilkan produk akhir yang banyak, stabil secara genetik, cocok untuk bahan baku sari tebu dan mampu menghasilkan PHB dan PHV, yang merupakan persyaratan ketat dalam laporan singkat proyek. Keseluruhan pabrik dibagi kedalam lima bagian terpisah: pra-pengolahan bahan baku, fermentasi, ekstraksi PHA, pemurnian dan peletisasi PHA, serta pemulihan aseton-air. Dalam tugas akhir ini, desain peralatan proses pemurnian dan peletisasi diselidiki lebih lanjut. Bagian pemurnian dan peletisasi bertujuan untuk mengendapkan PHA, mengeringkan dan membentuk produk padatan akhir sehingga menjadi produk PHA yang berbentuk pelet dengan diameter 3 mm. Dampak lingkungan telah diminimalisir semaksimal mungkin terutama dalam mencegah pelepasan aseton. Emisi debu, kebisingan, bau, dan gas buang adalah beberapa dari dampak lingkungan potensial yang diidentifikasi dan perlu dikelola secara efektif untuk mencegah kerusakan lingkungan.

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ABSTRACT

Plastic pollution is becoming an increasingly serious environmental issue and there is a growing push to phase out single use and non-biodegradable plastics. Polyhydroxyalkanoate (PHA) is a biodegradable and bioderived thermoplastic that shows great potential as a cost-effective replacement to the existing plastics in a variety of applications. The market is currently supply constrained and it is an opportune time to capitalize on this expanding market. A manufacturing facility to produce 5000 tonnes per annum of PHA bioplastic from sugarcane juice is to be designed. A range of manufacturing processes were evaluated to determine the most suitable process for this application. A pure culture of Ralstonia eutropha was the recommended bacteria to produce the PHA polymers as it is high yielding, genetically stable, suited to cane juice feedstock and capable of producing both PHB and PHV, which is a strict requirement in the project brief. The overall plant was split and designed in five separate sections: feedstock pre-treatment, fermentation, PHA extraction, PHA purification and palletization, as well as acetone-water recovery. In this paper, the purification and palletisation process equipment designs are further investigated. The purification and pelletising section is responsible for precipitating the PHA, drying and forming the final solid product. Environmental impacts have been minimised as much as possible with a particular focus on preventing acetone from being discharged. Dust, noise, odor, and flue gas emissions are among some of the potential environmental impacts identified that will need to be managed effectively in order to prevent environmental harm."