Hasfalina Che Man

Separation and Purification of Polyhydroxyalkanoates from Newly Isolated Comamonas sp. EB172 by Simple Digestion with Sodium Hydroxide

A simple, mild, and effective process for the recovery of intracellular polyhydroxyalkanoate from a newly isolated gram-negative wild-type bacteria Comamonas sp. EB172 was developed using sodium hydroxide. Various parameters such as sodium hydroxide concentration, digestion time, and temperature were examined for their effect on polyhydroxyalkanoate recovery. The results showed that polyhydroxyalkanoate with 88.6% purity and 96.8% recovery yield were obtained by incubating the dried cells with 0.05 M sodium hydroxide at 4°C for 1 h, followed by purification steps using ethanol and water. Removal of non-polymeric cellular materials from the Comamonas sp. EB172 was increased under alkaline solution as a result of enhanced cell wall permeability. In addition, the presence of glycerol in the polymer suspension proved that saponification of the lipid layer in the bacterial cell wall occurred due to sodium hydroxide reaction.

Phytoremediation Potential of Vetiver System Technology for Improving the Quality of Palm Oil Mill Effluent

Palm oil mill effluent (POME), a pollutant produced by the palm oil industry, was treated by the Vetiver system technology (VST). This technology was applied for the first time to treat POME in order to decrease biochemical oxygen demand (BOD) and chemical oxygen demand (COD). In this study, two different concentrations of POME (low and high) were treated with Vetiver plants for 2 weeks. The results showed that Vetiver was able to reduce the BOD up to 90% in low concentration POME and 60% in high concentration POME, while control sets (without plant) only was able to reduce 15% of BOD. The COD reduction was 94% in low concentration POME and 39% in high concentration POME, while control just shows reduction of 12%. Morphologically, maximum root and shoot lengths were 70 cm, the number of tillers and leaves was 344 and 86, and biomass production was 4.1 kg m−2. These results showed that VST was effective in reducing BOD and COD in POME. The treatment in low concentration was superior to the high concentration. Furthermore, biomass of plant can be considered as a promising raw material for biofuel production while high amount of biomass was generated in low concentration of POME.

Phytoremediation of domestic wastewaters in free water surface constructed wetlands using Azolla pinnata

abstract Two constructed wetlands, one with Azolla pinnata plant (CW1) and the other without (CW2) for treating domestic wastewaters were developed. Fifteen water parameters which include: Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), Total Suspended Solid (TSS), Total Phosphorus (TP), Total Nitrogen (TN), Ammoniacal Nitrogen (NH3N), Turbidity, pH, Electrical Conductivity (EC), Iron (Fe), Magnesium (Mg), Manganese (Mn), and heavy metals such as Lead (Pb) and Zinc (Zn) were analyzed using standard laboratory procedures. The experiments were conducted in two (dry and wet) seasons simultaneously. Results showed considerable reductions in all parameters and metals including Zn in CW1 compared with CW2 in the two seasons considered while Pb and Mn were not detected throughout the study. Zn concentration levels reduced significantly in both seasons just as removal efficiencies of 70.03% and 64.51% were recorded for CW1 while 35.17% and 33.45% were recorded for CW2 in both seasons. There were no significant differences in the removal efficiencies of Fe in both seasons as 99.55%, 59.09%, 88.89%, and 53.56% were recorded in CW1 and CW2 respectively. Azolla pinnata has proved effective in domestic wastewater phytoremediation studies.

Equilibrium studies and dynamic behavior of cadmium adsorption by palm oil boiler mill fly ash (POFA) as a natural low-cost adsorbent

AbstractThe highlight of this study is the adsorption properties and characterization of palm oil boiler mill fly ash (POFA) as a natural low-cost adsorbent for the removal of Cd(II) from aqueous solution. An array of batch adsorption studies has been done with the effects demonstrated by relevant parameters such as contact times, solution pH, adsorbent dosage, and initial Cd(II) concentration to investigate POFA performance. Energy-dispersive X-ray (EDX) analysis has shown that the structural surface of POFA containing porous carbon and revealing ion exchange may serve as one of the major mechanisms accountable for Cd(II) adsorption onto POFA. Fundamental batch investigations have implied that 80% of Cd(II) was removed in the first 30 min reaching equilibration, after only going through the process of agitation for 210 min. The Cd(II) uptake mechanism is specifically pH and concentration dependant with pH 7 being the optimum reading. A decreased adsorption capacity with an increased Cd(II) removal effici...

An Overview of the System of Rice Intensification for Paddy Fields of Malaysia

Objectives: The objective of this paper was to present a general overview of rice agronomic practices and transplanting operations by considering the interactions of soil, plant, and machine relationship in line with the System of Rice Intensification (SRI) cultivation practice. Methods: Some of the problems challenging Malaysian rice growers, as well as yield increase and total rice production in the last four decades, were first addressed and discussed. The trend in the world rice production between 1961 and 2014 was used to predict the production in 2020 and to show that Southeast Asian countries are expected to increase their production by 27.2%. Findings : A consistently increasing pattern from 3.1 tons/ha during 1981 to 4.1 tons/ha in 2014 was observed in the rice yield of Malaysia due to the advances in technology and improved farming operations coupled with integrated management and control of resources. Various literature were reviewed and their findings of the best transplanting practices were summarized to discuss how SRI contributes to the production of higher rice yield with improved transplanting practices through a more effective root system. Our review shows that wider spacing, availability of solar radiation, medium temperature, soil aeration, and nutrient supply promote shorter Phyllochrons which increase the number of tillers in rice. In this regard, modification and development of a transplanter that complies with SRI specification require determination of optimum transplanting spacing, seed rate, and planting pattern to significantly improve yield. Improvement: It was concluded that for maximum yield, the SRI method in Malaysia should emphasize on the planting of one seedling per hill with space of 0.25 m for optimum water consumption, nutrient and pest management.

The Pertinence of Microwave Irradiated Coconut Shell Bio-Sorbent for Wastewater Decolourization: Structural Morphology and Adsorption Optimization Using the Response Surface Method (RSM)

Palm oil mill effluent contains carcinogenic coloured compounds that are difficult to separate due to their aromatic structure. Though colour treatment using adsorption processes at lower pH (<4) have been reported effectual, due to its acidity the remediated effluent poses an environmental hazard as a result. Thus, the current study focused on achieving decolourization at neutral pH by enhancing the morphology of the coconut shell activated carbon (CSAC) using N2 as activating-agent with microwave irradiation heating. The microwave pretreated and non-pretreated CSAC were characterized using scanned electron microscopy (SEM), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) analysis. A significant modification in the porous structure with a 66.62% increase in the specific surface area was achieved after the pretreatment. The adsorption experimental matrix was developed using the central composite design to investigate the colour adsorption performance under varied pH (6–7), dosage (2–6 g) and contact time (10–100 min). At optimum conditions of neutral pH (7), 3.208 g dosage and contact time of 35 min, the percentage of colour removal was 96.29% with negligible differences compared with the predicted value, 95.855%. The adsorption equilibrium capacity of 1430.1 ADMI × mL/g was attained at the initial colour concentration of 2025 ADMI at 27 °C. The experimental data fitted better with the Freundlich isotherm model with R2 0.9851.

Review of optimum temperature, humidity, and vapour pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review

Abstract Greenhouse technology is a flexible solution for sustainable year-round cultivation of Tomato (Lycopersicon esculentum Mill), particularly in regions with adverse climate conditions or limited land and resources. Accurate knowledge about plant requirements at different growth stages, and under various light conditions, can contribute to the design of adaptive control strategies for a more cost-effective and competitive production. In this context, different scientific publications have recommended different values of microclimate parameters at different tomato growth stages. This paper provides a detailed summary of optimal, marginal and failure air and root-zone temperatures, relative humidity and vapour pressure deficit for successful greenhouse cultivation of tomato. Graphical representations of the membership function model to define the optimality degrees of these three parameters are included with a view to determining how close the greenhouse microclimate is to the optimal condition. Several production constraints have also been discussed to highlight the short and long-term effects of adverse microclimate conditions on the quality and yield of tomato, which are associated with interactions between suboptimal parameters, greenhouse environment and growth responses.