Umi Aisah Asli

Pineapple peel fibre biocomposite: Characterisation and biodegradation studies

In this study, pineapple peel fibre (PAPF) based low density polyethylene (LDPE) biocomposites for green packaging was studied. The PAPF was first being treated with alkali before compounded with LDPE. The mixture was compounded using twin screw extruder and the test samples were prepared using hot press machine. The compatibility of the PAPF as biocomposites was observed through the characterisation analysis and thermal properties and also the biodegradation analysis. Melt flow index (MFI) analysis was conducted to determine the process ability of the biocomposites. As the fibre loading in the biocomposites increases, the MFI values were decreased. The amount of water absorption was increased with the increases of PAPF loading due to the higher cellulose content. Thermal stability studies of biocomposites were undergoing thermogravimetry (TGA) and differential scanning calorimetry (DSC) analysis. Melting temperature (Tm) for the biocomposite was determined from the DSC analysis while the degradation temperature was determined by using the TGA analysis. The thermal properties of PAPF biocomposites were more or less the same as the LDPE properties. The biocomposites was buried in the soil for a month and exposed to fungi environment for 28 d for biodegradation analysis and the highest PAPF/LDPE loading biocomposites degraded the most. Therefore, PAPF biocomposites was compatible for green packaging.

Reduction of soil acidity for agriculture activities in Malaysian ultisols by rhodopseudomonas palustris

The potential of the phototrophic bacterium, Rhodopseudomonas palustris (R. palustris), to reduce the acidic soil pH of Malaysian Ultisols (Bungor Series) was investigated. The R. palustris was first adsorbed onto the dried pineapple leaves (DPL) before being applied. The most suitable broth condition for the bacterium that could be adsorbed onto the DPL was identified. Different conditions and amounts of R. palustris adsorbed onto the DPL % (w/w) were tested in soils where the soil pH was monitored. It was found that the maximum cell adsorption onto the DPL was obtained using an initial cell concentration of 1.5 x 107 colony-forming units (CFU) mL-1, at pH 8.0 with the ionic strength of 5 mmolL-1 ammonium nitrate (NaNO3). The R. palustris was adsorbed onto the DPL surface area of 64.33 A. The acidic soil was treated with R. palustris adsorbed onto the DPL by direct application. The calcium carbonate (CaCO3) was introduced as a benchmark to reduce the soil acidity. The results showed that, with the application of R. palustris adsorbed on 5.0 % (w/w) of DPL, the soil pH was improved from 4.9 to more than 6.0 after 12 d of application. This improved soil pH will make the soil more applicable for agricultural activity.