Mohd Azizi Che Yunus

A REVIEW OF MIXED REVERSE MICELLE SYSTEM FOR ANTIBIOTIC RECOVERY

This article discusses the application of mixed reverse micelles in downstream processing of antibiotics. Purification and recovery processes for antibiotics in downstream processing are major expenses, about 70% of the total cost of production, giving them a significant impact on manufacturing cost. Moreover, there are a number of challenges and difficulties in the separation process requirements for antibiotics, since the mixture is quite complex, with broth, hazardous solvents, by-products, intermediate material, and impurities; in addition, antibiotics are easy to denature. Therefore, the development of effective separation techniques is required to produce high-purity of biomaterials. The use of reverse micelles is thought to be among the most promising due to the processs high selectivity and efficiency. Most studies on reverse micelle extraction technology have been performed by using anionic surfactant sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT). However, the activities of antibiotics hosted in this type of surfactant have a significant effect due to the strong electrostatic and hydrophobic interaction between antibiotic and surfactant molecules. Due to these problems many alternatives have been developed recently, and reverse micelles have high potential in the purification of biomolecules. Therefore, this review discusses the ability of mixed ionic-nonionic reverse micelles to provide a safe microenvironment for antibiotics by maintaining the strength of attraction between the reverse micelle molecule and the antibiotic while avoiding the denaturation of the antibiotic. The article highlights the potential of mixed ionic-nonionic reverse micelle technology as a tool of antibiotic recovery from various mediums.

Effect of heat treatment on copper removal onto manure-compost-activated carbons

The work was aimed to investigate the effect of heat treatment of manure-compost-based activated carbons on the adsorption of copper from aqueous solution. Activated carbons were characterized according to physical structures and surface functional groups. All equilibrium data of activated carbons formerly treated at different temperatures obeyed Langmuir model to linear approximation. Results showed that copper ions favorably adsorbed onto the mesopores at lower equilibrium concentrations and subsequently changed to the micropores at higher equilibrium concentrations. It was found that the increase in electron density upon heat treatment offered higher tendency for the uniform amount of protons to occupy the surface sites. Analysis of Scatchard plots suggested that the affinity driven by the mesopores toward copper ions was stronger than that of the micropores.

Extraction of peanut skin oil by modified supercritical carbon dioxide: Empirical modelling and optimization

ABSTRACT Peanut skin is a waste by-product from peanut industries. It is rich in antioxidants and bioactive compounds. Therefore, the objective of this study was to empirically model and optimize supercritical CO2 extraction of oil from peanut skin. The extraction conditions were pressure (100, 200 and 300 bar), temperature (313, 328 and 343 K) and rate of modifier ethanol (0.075, 0.15 and 0.225 mL/min). The extraction process was subsequently examined using modified Brunner and Esquivel models. The optimum conditions for extraction peanut skin oil were 279 bar, 70°C and rate of modifier of 7.5% with a maximum yield of peanut skin oil of 0.83 g and initial slope of 0.568 g/min.

Optimization of supercritical carbon dioxide extraction of Piper Betel Linn leaves oil and total phenolic content

Supercritical Carbon Dioxide (SC-CO2) Extraction was applied to extract piper betel linn leaves. The piper betel leaves oil was used antioxidant, anti-diabetic, anticancer and antistroke. The aim of this study was to optimize the conditions of pressure, temperature and flowrate for oil yield and total phenolic content. The operational conditions of SC-CO2 studied were pressure (10, 20, 30 MPa), temperature (40, 60, 80 °C) and flowrate carbon dioxide (4, 6, 8 mL/min). The constant parameters were average particle size and extraction regime, 355pm and 3.5 hours respectively. First order polynomial expression was used to express the extracted oil while second order polynomial expression was used to express the total phenolic content and the both results were satisfactory. The best conditions to maximize the total extraction oil yields and total phenolic content were 30 MPa, 80 °C and 4.42 mL/min leading to 7.32% of oil and 29.72 MPa, 67.53 °C and 7.98 mL/min leading to 845.085 mg GAE/g sample. In terms of optimum condition with high extraction yield and high total phenolic content in the extracts, the best operating conditions were 30 MPa, 78 °C and 8 mL/min with 7.05% yield and 791.709 mg gallic acid equivalent (GAE)/g sample. The most dominant condition for extraction of oil yield and phenolic content were pressure and CO2 flowrate. The results show a good fit to the proposed model and the optimal conditions obtained were within the experimental range with the value of R2 was 96.13% for percentage yield and 98.52% for total phenolic content.

Optimisation of squalene from palm oil mesocarp using supercritical carbon dioxide

A promising technique of Green Supercritical Carbon Dioxide (SC-CO2) process was developed for the extraction of squalene from palm oil mesocarp. In this study, the green SC-CO2 was compared with the conventional Soxhlet extraction for quantify the best extraction method. The independent variables in SC-CO2 were selected as follows: temperature (45-75°C), pressure (16-30 MPa) and CO2 flow rate (2-5 ml/min). The responses are oil yield and the concentration of squalene. On the other hands, the conventional soxhlet extraction condition was type of solvents. Furthermore, the conditions of SC-CO2 extraction for squalene and oil yield were optimized by response surface methodology (RSM) following Box-Behnken Design (BBD). The optimum conditions were at pressure (16 MPa), temperature (45.01°C) and CO2 flow rate (2 ml/min) and the concentration of squalene was 0.506%. Meanwhile for soxhlet extraction method showed the concentration of squalene was 0.143% with chloroform. In overall, the results indicated the green SC-CO2 was the best an alternative technique.

Solubility model of arachis hypogea skin oil by modified supercritical carbon dioxide

ABSTRACT The main objective of this study was to determine the solubility of peanut (Arachis Hypogea) skin oil using modified supercritical carbon dioxide (SCCO2). The solubility was measured at pressure ranging from 100 to 300 Bar, temperature of 313 to 328 K, and rate of modifier from 0.075 to 0.225 mL/min. The solubility of extraction was ranging from 1.12 to 7.73 mg/min. The Chrastil, modified Chrastil, Del Valle Aguilera (DVA), Adachi-Lu, and Gordillo as empirical models were tested to fit the experimental data. Solubilities from these models followed the average absolute relative deviations (AARD) from experimental data: Chrastil, modified Chrastil, DVA, Adachi-Lu, and Gordillo with AARD of 8.54%, 8.26%, 19.41%, 9.24%, and 20.62%, respectively. Modified Chrastil model provide the best fit.

Effect of operating conditions on catechin extraction from betel nuts using supercritical CO2-methanol extraction

ABSTRACT In this work, the effect of extraction parameters on catechin extraction from betel nuts was studied. The supercritical carbon dioxide extraction parameters were pressure, temperature, and solvent flow rate while using average particle size of 177.5 μm and 5% (v/v) methanol as modifiers. Detection and quantification of catechin were achieved using HPLC analysis. The highest amount of extract and catechin concentration were 34.00 mg extract/g sample and 565.38 ppm of catechin obtained at 30 MPa, 70°C, and 4 mL/min. The results given by optimization tools suggest the same operating conditions with less than 3% difference.

Optimisation of supercritical CO2 extraction of red colour from roselle (Hibiscus Sabdariffa Linn.) calyces

Roselle (Hibiscus sabdariffa Linn.) is a local tropical plant widely cultivated in Malaysia. Roselle produces red edible calyces which contain intense red pigments of anthocyanins. Supercritical fluid extraction with carbon dioxide (CO2) is a particularly suitable isolation method for natural materials and gives an alternative to replace the mass usage of non-polar organic solvents in conventional methods. The advantage of using CO2 as solvent is that no organic solvent residual inside the extracted sample since CO2 is in gas form at room temperature. The red colour extract by using CO2 is easier to be separated by decompression and has high recovery percentage. The objective of this research was to optimise the supercritical carbon dioxide (SC-CO2) extraction conditions for obtaining the maximum yield of red colour extract. SC-CO2 extraction of red colour of roselle was performed with ethanol as modifier at the pressures of 8, 10 and 12 MPa, temperatures of 50, 60 and 70 °C while the percentage of modifier flow rates was at 5, 7.5 and 10 %. Full 33 factorial design was used to optimise operating conditions for the extraction yield of roselle calyces in SC-CO2.The other parameters were kept constant, such as total flow rate of CO2 and modifier (6 mL/min), ratio of modifier (75 % of ethanol), the average particle size used (350 μm) and extraction regime (70 min). The findings revealed that the extraction yield was significantly influenced by three main effects investigated in this study, with p-value smaller than 0.05. The optimum operating conditions obtained for SC-CO2 extraction of red colour extract were 8.90 MPa, 70 °C, and 9.49 % with predicted percentage yield of 26.73 %.

Bio-polishing sludge adsorbents for dye removal

Abstract The objective of this work is to evaluate the removal of methylene blue dye by bio-polishing sludge-based adsorbents. The adsorbents were characterized according to the specific surface area, pH upon the treatment and surface functional groups. The adsorption of dye was carried out at room temperature, and the adsorption data were analyzed using the isotherm and kinetics models. The bio-polishing sludge is rich in ash content, and the presence of surface functional groups varied with the treatment strategies. The specific surface area of adsorbents is between 7.25 and 20.8 m2/g. Results show that the maximum removal of methylene blue by sludge adsorbents was observed to have the following order: untreated sludge (SR) > zinc chloride-treated (SZ) > microwave-dried (SW) = potassium carbonate-treated (SK) > acid-washed (SH). The maximum adsorption capacities for SR and SZ as predicted by the Langmuir model are 170 and 135 mg/g, respectively. Although SR demonstrates a higher maximum removal than SZ, the latter exhibits greater removal intensity and rate constant even at high dye concentration. The bio-polishing sludge is a promising adsorbent for dye wastewater treatment.