The Influence of Glycerol on Mechanical, Thermal and Morphological Properties of Thermoplastic Tapioca Starch Film

Thermoplastic tapioca starch (TPTS) film was made by tape casting. The viscoelastic behaviour, thermal degradation and surface morphology were investigated using Dynamic mechanical analysis (DMA), Thermogravimetric analysis (TGA) and Scanning electron microscope (SEM) respectively. The DMA result shows that the storage modulus as well as loss modulus of the TPTS films with 0, 5, 10, 15 and 20% glycerol appears to reduce with increase in glycerol content due to phase relaxation as a result of molecular interaction of the starch molecules with glycerol molecules. Whereas, tan δ shows the effect of temperature is higher on the TPTS film with low glycerol content. The thermal degradation of the TPTS is more susceptible to heat as shown by curve 2(e) for film sample with 20% glycerol, showing that higher glycerol content reduces thermal stability of the film. Even though, lowering of glass transition temperature of the TPTS films took effect with the higher concentration of glycerol which proves ease of processibility and workability of the film. The SEM micrographs of fracture surfaces indicate intermolecular miscibility and surface adhesion increases with higher fraction of glycerol content

Phenotypic identification of Penicillium spp. isolated from clinical wastes based on microstructure characteristics

Aims: The present study aimed to recognize the microstructure of conidiophores and spores of Penicillium spp. which were isolated from clinical wastes. Methodology and results: The isolates of Penicillium spp. were obtained from the solid clinical wastes on V8A medium and purified by single spore method. The culture characteristics were described in five culture media included; Czapek Yeast Extract Agar (CYA); Malt Extract Agar (MEA), Potato Dextrose Agar (PDA), Sabouraud Dextrose Agar (SDA) and Czapek-Dox Agar (CZ) while the conidiophores and spores were described using light and Scanning Electronic Microscope (SEM). Penicillium spp. observed some differences in their culture characteristics. Among 11 Penicillium species isolated in this study and identified based on culture and microscope morphology. Five species including P. simplicissium, P. waksmanii, P. corylophilum and P. decumbens as well as one species identified as T. wortmannii were described in detail using SEM. Conclusion, significance and impact of study: The study revealed that the microstructure of the fungal spores and conidiophores play an important role in the taxonomy of fungi species based on the phenotypic method