Sintesis dan Karakterisasi Selulosa Asetat dari A-Selulosa Fiber Cake Kelapa Sawit

Penelitian tentang sintesis dan karakterisasi selulosa asetat dari ?-selulosa fiber cake kelapa sawit ini telah dilakukan dengan menggunakan anhidrida asetat sebagai acetylating agent. Penelitian ini bertujuan untuk mendapatkan selulosa asetat dengan klasifikasi selulosa diasetat yang memiliki yield produk yang tinggi, mempelajari pengaruh variasi rasio selulosa:anhidrida asetat, waktu asetilasi, dan suhu asetilasi untuk mendapatkan selulosa asetat dengan kondisi yang optimal dari ?-selulosa fiber cake kelapa sawit. Penelitian ini menggunakan variasi rasio selulosa:anhidrida asetat (1:5; 1:10; 1:15), waktu asetilasi (0,5; 1; 1,5; 2; 2,5)jam, dan suhu asetilasi (25 dan 40) oC menghasilkan 30 sampel produk. Hasil penelitian menunjukkan bahwa selulosa asetat yang didapatkan berupa selulosa diasetat dengan bentuk padatan berupa serbuk, berwarna putih gading, dan tidak berbau serta memiliki kadar ?-selulosa sebesar 84,29 % dengan kadar air 9,16 % pada rasio selulosa:anhidrida asetat (1:10), waktu asetilasi 1,5 jam, dan suhu asetilasi 40oC dengan nilai yield produk, kadar asetil, dan derajat substitusi berturut-turut 49 %, 39,97 %, dan 2,5. Research on the synthesis and characterization of cellulose acetate from palm oil ?-cellulose fiber cake has been carried out using acetic anhydride as an acetylating agent. This study aims to obtain cellulose acetate with cellulose diacetate classification which has a high product yield, study the effect of variations in the ratio of cellulose:acetic anhydride, acetylation time, and acetylation temperature to obtain cellulose acetate with optimal conditions from palm oil ?-cellulose fiber cake. This study used variations in the ratio of cellulose:acetic anhydride (1:5; 1:10; 1:15), acetylation time (0.5; 1; 1.5; 2; 2.5) hours, and acetylation temperature (25 and 40) oC produces 30 product samples. The results showed that the cellulose acetate obtained was in the form of cellulose diacetate with a solid form in the form of powder, ivory white, and odorless and had 84.29% of a-cellulose content with 9.16% of a moisture content at the ratio of cellulose:acetic anhydride (1 :10), acetylation time 1.5 hours, and acetylation temperature 40oC with product yield, acetyl content, and degree of substitution 84.6%, 39.97%, and 2.5, respectively.

Arabidopsis GELP7 is plasma membrane-localized acetyl xylan esterase, and its overexpression improves saccharification efficiency.

Acetyl substitution on the xylan chain is critical for stable interaction with cellulose and other cell wall polymers in the secondary cell wall. Xylan acetylation pattern is governed by Golgi and extracellular localized acetyl xylan esterase (AXE). We investigated the role of Arabidopsis clade Id from the GDSL esterase/lipase or GELP family in polysaccharide deacetylation. The investigation of the AtGELP7 T-DNA mutant line showed a decrease in stem esterase activity and an increase in stem acetyl content. We further generated overexpressor AtGELP7 transgenic lines, and these lines showed a decrease in xylan acetylation in comparison with wild type plants. Therefore, we have named this enzyme as AtAXE1. The subcellular localization studies showed that the AtAXE1 enzyme is secreted out, associated with the plasma membrane and involved in xylan de-esterification post-synthesis. The cellulose digestibility was improved in AtAXE1 overexpressor lines without pre-treatment, after alkali and xylanases pre-treatment. Furthermore, we have also established that the AtGELP7 gene is upregulated in the overexpressor line of AtMYB46, which is a secondary cell wall specific transcription factor. This transcriptional regulation can drive AtGELP7 or AtAXE1 to perform de-esterification of xylan in a tissue-specific manner.

One-bath One-step Dyeing of Polyester/Cotton (PC) Blends Fabric With Disperse Dyes After Acetylation of Cotton

Usually, the two-bath dyeing process using disperse dyes and reactive dyes separately was employed for the dyeing of PC blends. The cost of the double bath, dyeing cycle, energy consumption and chemical consumption is quite higher than the one-step or single bath dyeing methods. In this study, the one-bath dyeing process using one kind of dye was investigated. Polyester cotton blends dyed in one-bath one-step dyeing methods with disperse dye after surface modifications of cotton by acetylation methods were studied. Surface modification of cotton was carried out using fibrous acetylation methods. The effect of acetic anhydride and time on percent acetyl content at room temperature was studied. Modified polyester/cotton was carried out in HTHP dyeing machine incorporates with different dye concentrations and dyeing temperature. Surface chemistry, thermal decomposition property and moisture regain of modified polyester/ cotton blend are evaluated. The color strength of the dyed fabrics and their fastness properties to washing, light, and rubbing as well as tear strength and abrasion resistance were evaluated. The effect of dye concentration and temperature color strength, tensile strength warp and weft direction was assessed. The optimum value for surface modification was obtained with a concentration of acetylation agent 16% and time of reaction 2.5 hours, gave percent acetylation of 34. An FTIR spectrum shows acetylation resonance. The experiment result of dyeing showed that the optimum value was obtained with dye concentration above 1% at a temperature of 120oC, warp tensile strength decreased by 12% and weft tensile strength was decreased by 9% from the control half-bleached fabric. Results of this study showed that a one-step one-bath dyed modified polyester/cotton blend with disperse dye fabric presents good fastness property compared with conventional two-bath dyed fabric as well as colour strength values.

Glycoconjugate vaccines against Salmonella enterica serovars and Shigella species: existing and emerging methods for their analysis

The global spread of enteric disease, the increasingly limited options for antimicrobial treatment and the need for effective eradication programs have resulted in an increased demand for glycoconjugate enteric vaccines, made with carbohydrate-based membrane components of the pathogen, and their precise characterisation. A set of physico-chemical and immunological tests are employed for complete vaccine characterisation and to ensure their consistency, potency, safety and stability, following the relevant World Health Organization and Pharmacopoeia guidelines. Variable requirements for analytical methods are linked to conjugate structure, carrier protein nature and size and O-acetyl content of polysaccharide. We investigated a key stability-indicating method which measures the percent free saccharide of Salmonella enterica subspecies enterica serovar Typhi capsular polysaccharide, by detergent precipitation, depolymerisation and HPAEC-PAD quantitation. Together with modern computational approaches, a more precise design of glycoconjugates is possible, allowing for improvements in solubility, structural conformation and stability, and immunogenicity of antigens, which may be applicable to a broad spectrum of vaccines. More validation experiments are required to establish the most effective and suitable methods for glycoconjugate analysis to bring uniformity to the existing protocols, although the need for product-specific approaches will apply, especially for the more complex vaccines. An overview of current and emerging analytical approaches for the characterisation of vaccines against Salmonella Typhi and Shigella species is described in this paper. This study should aid the development and licensing of new glycoconjugate vaccines aimed at the prevention of enteric diseases.

Effect of acetylation treatment on surface modified tapioca starches

Surface modified tapioca starch was developed by enzyme treatment (using STARGEN™ 002 enzyme) and alcohol-enzyme treatment. The effects of acetylation treatment on surface modified tapioca starches were evaluated for acetyl content (Ac%), degree of substitution (DS), morphology using scanning electron microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), thermal properties, and X-ray diffraction (XRD) patterns. After acetylation treatment, Ac% and DS value of the samples were significantly increased for acetylated (0.67% and 0.03), enzyme-acetylated (1.13% and 0.04), and alcohol-enzyme acetylated (1.76% and 0.07). The acetylation treatment led to the formation of a few starch granules due to the introduction of hydrophilic groups of acetyl molecules into starch granules. The incorporation of acetyl groups into starch molecules also was shown at peak 1750 cm-1 , 1369 cm-1 , and 1230 cm-1 in the FTIR spectra. The enzyme-acetylated and alcohol-enzyme acetylated starch granules retained the A-type crystalline structure with decreased in the gelatinization enthalpy (ΔH) after acetylation.

Chemical and Mechanical Differences between Historic and Modern Scots Pine Wood

Timber is one of the most common historic building materials, but relatively little is known about how it ages in situ. Here we investigate historic and modern Scots pine to determine any chemical or mechanical differences between them. Fourier-transform infrared (FTIR) microscopy was used to investigate differences in the chemical composition of Scots pine (Pinus sylvestris L.) timber, comparing small samples from historic beams about 500 years old with modern timber. The hemicellulosic acetyl content was reduced by about half in the historic samples, uniformly across the thickness of the beams. A chemical mechanism was therefore suggested for the loss of acetyl groups, as has been observed in paper. In paper, deacetylation and the resulting release of acetic acid are accompanied by loss of strength. Mechanical testing of the historic timber was difficult because the available length of the samples along the grain was only 20 mm. After developing a miniaturized compression test developed for the purpose, it was shown that the relative stiffness of the historic Scots pine samples was reduced by about half compared to modern material.

SYNTHESIS OF ACETATE CELLULOSA FROM THE PALM OIL EMPTY FLOOR THROUGH THE REACTION OF ACTIVATION

Acetate cellulose is cellulose whose hydroxyl group is replaced by an acetyl group. Celluloseacetate has a high enough attractiveness because it is biodegradable so it is environmentally friendly. The purpose of this study is to increase the acetyl content of cellulose acetate by theacetylation reaction. This study uses 25 grams of empty fruit bunches to get cellulose, the delignification process is carried out for 30 minutes with NaOH solution, and the bleachingprocess for 1.5 hours with H2O2 solution. Next, as much as 5 grams of cellulose was carriedout by the acetylation process by adding glacial CH3COOH solution, anhydrous CH3COOHsolution with a ratio of 1:10, 1: 12.5 and 1:15 (w / v) and H2SO4 as a catalyst, withtemperature variations of 40oC, 55oC and 70oC. Next, an acetyl concentration was analyzedby titration, and substitution degree analysis was carried out. The best results obtained fromthe two analyzes will be carried out the Fourier Transform Infrared (FTIR) test and theScanning Electron Microscope (SEM) test. Acetyl content obtained was 8,152 - 24,58% andthe degree of substitution obtained was 0,3 - 1,2%.