Judul Karya Ilmiah: Pendugaan kelarutan pati dalam air dari berbagai sumber tumbuhan dengan pendekatan teori Flory Huggins. Pendahuluan ditulis dengan baik, latar belakang juga dijabarkan dengan permasalahan yang ada dan menunjukkan urgensi penelitian yang ditunjukkan dengan referensi yang digunakan sekitar 19 bagian. Hal ini dibuktikan dengan total referensi yang digunakan sekitar 57, yang digunakan dalam pembahasan lebih dari 40 buah.
Estimation of water solubility of starch from different botanical sources using the Flory Huggins theory approach. Data on the solubility of starch in water are essential for determining the appropriate use of starch and designing starch-based nutritional products. A newly developed solubility model as a combination of the Clausius-Clapeyron relation and the Flory Huggins theory was fitted to data on the solubility of starches in water.
总之，Flory Huggins 方法可以用作估计淀粉水溶性的有力工具。
Extraction of essential oil from ultrasound pretreated citronella grass (cymbopogon Nardus) leaves by Hydro-. Essential Oil of Ultrasound Pretreated Citronella Grass (cymbopogon Nardus) Leaves by Hydro-distillation Method, Chemical Engineering Transactions. Global demand for essential oil derived from citronella grass (Cymbopogon nardus) leaves as fragrance, aroma and medicinal ingredients has been steadily increasing to commercial scale for decades.
Therefore, a research is being conducted to improve the production capacity of citronella grass essential oil through ultrasonic pretreatment. In this study, the effect of various operating parameters, such as leaf particle size (soil, 5 mm and 10 mm), ultrasonic pretreatment time (10, 20 and 30 min) and leaf particle mass on withdrawing water volume (SW) ratio (1:4.0 to 1:12.0) on the essential oil yield. The chemical and physical properties of the citronella oil were also determined, namely bioactive components, specific gravity, refractive index and colour.
The experimental results indicate that increased ultrasound pretreatment time and S/W ratio contributed to the improvement of oil yields by up to 56.94 % and 19.59. The GC-MS analysis proved that citronella oil mainly contains citronellal, geraniol, neral and geranial. Physical properties evaluation also revealed that the specific gravity, refractive index and color of the extracted citronella oil were of acceptable ranges.
The results indicated that the increase in S/W ratio and ultrasonic pretreatment time potentially increases the extraction yield.
July 2021
Combining the reaction simultaneously with separation inside a single process unit or commonly known as reactive separation technology is widely studied today as it would provide mutual benefits for both enzymatic catalysis and membrane separation process. Alcohol dehydrogenase (ADH) at 0.10 g/L (dissolved in 0.10 M Tris-HCl buffer) was immobilized on commercially available PES and PVDF membrane at pH 7 and TMP 2 bar by reverse filtration method. Then, the immobilized enzyme was subjected to the biocatalytic conversion of formaldehyde to methanol.
The immobilization process successfully immobilized 87.67% and 70.94% of ADH enzyme in/on PVDF and PES membrane, respectively. The following reaction was able to convert formaldehyde to methanol up to 90% conversion and a high biocatalytic productivity of 460 mmol CH3OH/mgenzymeh for PVDF membranes. This study showed that the immobilization of ADH on a polymer membrane could increase the loading of the enzyme and also preserve its activity for the simultaneous conversion and separation of formaldehyde to methanol.
The most beneficial part of a biocatalytic membrane with enzymes physically coupled in/on the membrane is the localized biocatalysis and the associated separation of the reactants and products (Charcosset et al.). The membrane placed in the biocatalytic reactor could function as a contactor (selective barrier). The porous structure of the membrane allows enzyme reuse, prevents product inhibition and even helps stabilize the enzymes, which would then enable a continuous process. can make (Luo, Meyer, et al.
The immobilization of enzymes within the porous structure of a solid can promote a complete distribution of the enzyme over the entire surface and bypass the interaction with the hydrophobic external interface, such as air bubbles from. Enzyme immobilization in/on the membrane can be achieved by covalent binding, cross-linking, adsorption and entrapment (Sheldon and van Pelt 2013). Covalent binding and target crosslinking techniques to functionalize the membrane surface with multifunctional chemicals ensure a strong chemical bond between the enzyme and the membrane (Mateo et al. 2007).
At the same time, a strong bond can change the structure of enzymes and can cause inactivation or decrease in activity (Bailey and Ollis 1986;. Immobilization of enzyme by physical adsorption is simple and easy, but enzyme desorption can easily occur. CONTACT Fauziah Marpani fauziah176@uitm.edu.my Integrated Separation Technology Research Group (i-STronG), Faculty of Chemical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/gcec.
