The brittleness of polylactic acid (PLA) has always limited its usage, although it has good mechanical strength. In this study, flexibility of PLA/starch (PSt) blend was enhanced using epoxidized palm oil (EPO) as the green plasticizer. The PLA/starch/EPO (PSE) blends were prepared while using the solution casting method by fixing the content of starch and varying ratio of EPO. The thermal properties, such as glass transition temperature (T_g), melting temperature (T_m), and crystallization temperature (T_cc) were decreased by increasing the amount of EPO into PSt, indicating that EPO increases the chain mobility. Thermogravimetric analysis (TGA) showed that thermal degradation resistance of PSE was higher when compared to PSt. The mechanical testing revealed that EPO at all contents improved the mechanical properties, such as increment of the elongation-at-break and impact strength. Whereas, dynamic mechanical analysis showed that the addition of filler into PLA decreased the storage modulus of PLA. The carbonyl group of the aliphatic ester remained the same in the PSE blends. The morphological study verified the ductility of PSE blends surface when compared to the brittle surface of PSt. As for the soil burial tests, EPO accelerated the degradation of blends. From these results, it can be concluded that EPO improved the flexibility of PLA blends.

The usage of non-degradable polymer as the main matrix for a cosmetic patch raises concern, as it can cause environmental pollution when discarded in landfill. Thus, biodegradable polylactic acid (PLA) was chosen in this study, as PLA has non-toxic properties and similar mechanical properties to conventional plastic materials. An active ingredient in a cosmetic patch serves the purpose of providing beneficial ingredients to the skin; therefore, phycocyanin, an extract from spirulina, was chosen, as it possesses antioxidant and anti-inflammatory properties. Alginate was also incorporated with the phycocyanin for fabrication onto the PLA matrix. A preliminary study was first carried out to identify the antioxidant properties and cytotoxic effect of the phycocyanin on skin cells. It was observed that phycocyanin had no cytotoxic effect on the skin and showed good antioxidant activity. PLA/phycocyanin–alginate composite was fabricated using a solvent casting method, and optimization of preparation conditions (phycocyanin/alginate ratio, stirring time, and temperature) were carried out using the one-factor-at-a-time (OFAT) method with responses of elongation at break and releasing properties. Attenuated total reflectance (ATR)–FTIR analysis was also conducted to further analyze the functional group of the composites. Surface morphologies were observed for samples before and after the releasing test. From the analyses conducted, PLA/phycocyanin–alginate composite prepared at a phycocyanin/alginate ratio of 40/60 for 20 h at 20 °C gave the best properties in terms of flexibility of film and releasing properties of phycocyanin.

Banana fiber (BF) is a renewable resource which can be a good reinforcer to polylactic acid, enhancing the polymers stiffness and accelerating biodegradability rates. However, due to the difference in nature between banana fibers (hydrophilic) and polylactic acid (hydrophobic), a good adhesion between the fiber and the matrix cannot be achieved. To tackle the problem, the fibers were chemically treated using sodium hydroxide under three factors (temperature, concentration, and treatment time). The factors interactions were given by response surface methodology and the statistical interactions were observed by ANOVA. Alkaline effect on fiber’s morphology, composition, mechanical, and morphological properties of composites produced were observed. Young’s modulus values have increased substantially compared to untreated fiber’s composites, with a slight increase in the tensile strength values. However, the elongation at break values have slightly dropped with the fiber’s alkaline treatment. Scanning electron microscope observations had shown a successful removal of impurities (e.g. hemicellulose, wax) and between the fiber’s strands, and an improvement of surface structure. Fourier-transform infrared spectroscopy analysis showed the successful removal of impurities, and interaction between PLA and banana fibers.

Microbial fuel cell (MFC) is an alternative approach in generating renewable energy by utilising bacteria that will oxidize organic or inorganic substrates, producing electrons yielded as electrical energy. Different species of exoelectrogenic bacteria capable of generating significant amount of electricity in MFC has been identified, using various organic compounds for fuel. Soil sample taken from rice paddy field is proven to contain exoelectrogenic bacteria, thus electricity generation using mixed culture originally found in the soil, and pure culture isolated from the soil is studied. This research will isolate the exoelectrogenic bacterial species in the rice paddy field soil responsible for energy generation. Growth of bacteria isolated from the MFC is observed by measuring the optical density (OD), cell density weight (CDW) and viable cell count. Mixed bacterial species found in paddy field soil generates maximum power of 77.62 μW and 0.70 mA of current. In addition, the research also shows that the pure bacterium in rice paddy field soil can produce maximum power and current at 51.32 μW and 0.28 mA respectively.

Scarcity in fuel from fossil fuel has led to exploration of potential substitutes from renewable sources. Biodiesel as one of renewable energy sources is identified as cleaner alternative to petroleum fuel. This paper reports on the study of potassium carbonate, K₂CO₃ sourced from pineapple and orange peels as heterogeneous catalyst for biodiesel production. K₂CO₃ was produced by drying of fruit peel prior to calcination at temperature ranged from 700°C to 1000°C for 2 to 4 hours. To determine the physicochemical properties of the resulting ash, Fourier transform infrared (FTIR) and Scanning electron microscopy (SEM) analysis were employed for the characterization of the solid. Through FTIR analysis, the presence of carbonate was confirmed while SEM analysis revealed the morphological properties of the catalyst. Biodiesel with highest yield of 95.6% was produced at 60°C, 2.75 wt% of catalyst and 12:1 molar ratio of methanol to oil.

The application of cassava starch in the biopolymers industry has been growing significantly due to its low cost, good oxygen barrier in the dry state, and biodegradability. Plant culture technology is an alternative to traditional propagation as it does not require large areas for production, has a higher rate of multiplication, and produces disease-free plants. However, the application of cassava callus culture for starch production is limited. This study focuses on identifying the significant culture parameters for a maximum Rayong cultivar cassava callus growth and evaluation of its starch content. Cassava stems petiole and leaf explants were cultured on MS medium containing different combinations of 2,4-D (8, 12, and 15 mg/L) and BAP (1, 3, and 5 mg/L) under three light conditions (0, 16, and 24 h). The screening of the most influential parameter was done using the 2-level Factorial Design in Design Expert v13 by analyzing the frequency of callus formation. All leaf explant turned brown with no callus induction. The highest frequency of callus formation derived from stem petiole explant was achieved by the combination of 8 mg/L 2,4-D and 1 mg/L BAP under the light condition (75%) followed by 8 mg/L 2,4 D + 1 mg/L BAP under the dark condition (50%). Based on the ANOVA analysis, the individual supply of 2,4-D and BAP respectively, have a negative effect on callus formation while the combination of 2,4-D and BAP has a positive effect. Light supply did not significantly affect cassava callus formation. The amount of starch in the cassava callus was then investigated using an iodine test which yielded 0.21% of the total weight of the callus (0.0101g). The amount of starch is relatively low considering that the callus was not grown under the optimum condition for starch production. The findings of this study open prospects for future research in cassava cultures in favor of starch production. ABSTRAK: Penggunaan kanji ubi kayu dalam industri biopolimer telah meningkat secara mendadak disebabkan oleh faktor kosnya yang rendah, rintangan oksigen yang baik dan sifat keterbiodegradasi. Teknologi kultur tisu tumbuhan merupakan alternatif kepada pembiakan secara tradisional yang mana teknologi ini tidak memerlukan kawasan penanaman yang luas, penghasilan yang lebih singkat dan menghasilkan tumbuhan bebas penyakit. Walau bagaimanapun, kajian mengenai penggunaan kanji dari kultur ubi kayu masih belum meluas. Kajian ini bertujuan mengenal pasti parameter penting dalam pertumbuhan maksimum kalus kultivar ubi kayu Rayong dan kandungan kanjinya. Eksplan dari tangkai petiol dan daun ubi kayu dikulturkan dalam medium MS yang mengandungi pelbagai kombinasi hormon tumbuhan 2,4-D (8, 12 dan 15 mg/L) dan BAP (1, 3 dan 5 mg/L) di bawah tiga tempoh masa pencahayaan (0, 16 dan 24 jam). Saringan parameter paling berpengaruh dilakukan menerusi reka bentuk faktorial 2-peringkat perisian Design Expert v13 melalui analisa frekuensi pembentukan kalus. Semua eksplan daun telah bertukar dari hijau ke perang dan tidak menunjukkan induksi kalus. Bagi eksplan batang daun, frekuensi pembentukan kalus tertinggi diperoleh dari kombinasi 8 mg/L 2,4-D dan 1 mg/L BAP di bawah pencahayaan 24 jam (75%) diikuti dengan 8 mg/L 2,4 D + 1 mg/L BAP di bawah pencahayaan malap (50%). Berdasarkan analisis ANOVA, medium 2,4-D dan BAP masing-masing menunjukkan kesan negatif kepada pembentukan kalus, sementara kombinasi 2,4-D dan BAP memberikan kesan positif. Dapatan ini menunjukkan bahawa pencahayaan tidak signifikan terhadap pembentukan kalus kultur ubi kayu. Kandungan kanji di dalam kalus ubi kayu kemudiannya diuji dengan larutan iodin, dan menunjukkan dapatan sebanyak 0.21% dari berat kalus (0.0101 g). Secara relatif, nilai ini adalah rendah memandangkan eksperimen ini bukan dihasilkan di bawah keadaan optimum bagi pembentukan kanji. Hasil kajian ini membuka peluang kepada kajian-kajian lain di masa hadapan dalam penghasilan kanji dari kultur tisu ubi kayu.