Repeated exposure of jacket plum (Pappea capensis) micro-cuttings to indole-3-butyric acid (IBA) improved in vitro rooting capacity

The objective of the trial was to determine an effective propagation protocol for jacket plum (Pappea capensis) tree species. Experiments on in vitro propagation and rooting of stem cuttings were carried out. Dipping stem cuttings in half strength Murashige and Skoog (MS) media for 12 h prior to application of rooting hormones improved bud break and prolonged survival of stem cuttings on a mist bed. Early leaf loss was observed for stem cuttings planted without MS treatment. However, rooting was poor (11% for cuttings pre-treated in MS and 0% for those not pre-treated). For micro-propagation, significant differences (P < 0.05) in shoot multiplication and root regeneration were found. MS media supplemented with 2.0 mg l–1 benzylaminopurine was superior in the number of micro-shoots produced. Rooting capacity of micro-cuttings was improved from 42% to 64% when MS media supplemented with 0.5 mg l–1 IBA were repeated for the micro-cuttings that initially failed to root. There was 70% survival rate of plantlets after hardened off.The financial support from the Federal Ministry of Economic Cooperation (BMZ/GTZ), Germany through the World Agroforestry Centre (ICRAF) Southern Africa Regional Programme, Agro-Forest and Bio Energy Association and Invest North West, South Africa is acknowledged

Esterification of free fatty acids in used cooking oil using ion-exchange resins as catalysts: An efficient pretreatment method for biodiesel feedstock

The esterification of used cooking oil (UCO) with methanol was studied using different types of ion-exchange resins, that is, Purolite D5081, Purolite D5082, and Amberlyst 36. Several catalyst characterization analyses (elemental analysis, surface area measurement, particle size distribution analysis, scanning electron microscopy analysis, true density measurement, and acid capacity analysis) have been conducted in the screening stage. Of all of the catalysts investigated, Purolite D5081 resin showed the best catalytic performance and was selected for further experimental studies. The esterification process was carried out in a jacketed stirred batch reactor for 8 h. Elimination of mass transfer resistances and the effect of catalyst loading (0.5–1.5% w/w), reaction temperature (50–65 °C), and methanol to UCO feed mole ratio (4:1–12:1) on the conversion of FFAs were investigated. The highest FFAs conversion was found to be 92%, at a catalyst loading of 1.25% w/w, 60 °C reaction temperature, 6:1 methanol to UCO molar ratio, and stirring speed of 475 rpm. During the reusability study, the conversion of catalyst dropped by 8–10% after each reutilization cycle. Several experiments have been conducted through the homogeneous contribution study, and the results confirmed that both resin pore blockage and sulfur leaching are dominant factors that decrease the catalytic performance of Purolite D5081 ion-exchange resin