This study was carried out to evaluate the potential of plastic synthesized using bio-based starch. The method began with extraction of starch from chosen tubers with high content of starch; potato and yam. The samples were first grated, grinded and strained to obtain crude starch, which then centrifuged and rinsed to get pure starch. The starch was then reacted with hydrochloric acid to breakdown amylopectin to prevent the starch from becoming plastic-like. Finally, propan-1,2,3-triol was added as a plasticizer to increase the elasticity of the product. The chemical, mechanical, and thermal properties of the products were analyzed using Fourier transform infrared (FTIR), tensile strength tester and Thermogravimetric analysis (TGA). The FTIR spectra of the product displayed the presence of O-H, C-H, C=O and C-O absorption peaks, which indicate the formation of bioplastic has already occured. The tensile strength obtained for potato and yam starch-based bioplastic are 0.6 MPa and 1.9 MPa, respectively. The result gained from TGA showed that 50% weight loss occurred at 250°C for potato and 310°C for yam-based plastic. The highly biodegradability of the plastic was proven using soil burial test, which observed the percentage of soil biodegradation for potato and yam-based bioplastic in 1 week duration is 43% and 26%, respectively. These bio-based plastics have exhibited good thermal and mechanical properties with high biodegradability that makes them a suitable alternative for the existing conventional plastics.

No abstract

Antimicrobial peptides (AMP) are key components of an innate immune response which represent immediate action of the defence mechanism of an organism.  It is considered a novel therapeutic agent due to its abundance in nature and a broad range of defence activity against microbial. Preceding research has shown that scygonadin AMPs isolated from seminal plasma of mud crab had the potential as a novel antimicrobial agent. However, its cytotoxicity properties on cultured cells have never been experimentally addressed. In this study, the scygonadin protein was expressed in vitro, followed by cytotoxicity assessment via MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. A full-length sequence of the scygonadin gene of 387 bp was cloned into pBAD/Myc-His A vector and expressed in TOP10 cells. The protein expression was induced, purified and quantified before being subjected to cytotoxicity analysis. Next, an African green monkey kidney (Vero) cell was chosen to evaluate the cytotoxicity level of scygonadin in vitro. A total of 1x104 cells/mL were seeded into a 96-well plate before being treated to various concentrations of scygonadin protein and hydrogen peroxide as a positive control for the toxicity test.  The cells’ viability treated with scygonadin AMP and hydrogen peroxide was also verified with fluorescent analysis. The result demonstrated that the scygonadin did not cause any cytotoxicity effects while hydrogen peroxide showed an IC50 value at 0.003mM and this was further confirmed by fluorescent staining analysis. The absence of scygonadin toxicity in cells indicates its potential for biopharmaceutical use.