Publications by authors named "Manel Ziadi"

2 Publications

  • Page 1 of 1

Evaluation of the Efficiency of Ethanol Precipitation and Ultrafiltration on the Purification and Characteristics of Exopolysaccharides Produced by Three Lactic Acid Bacteria.

Biomed Res Int 2018 18;2018:1896240. Epub 2018 Sep 18.

National Research Center for Materials Science, Borj-Cedria Technopark, BP N°73, 8027 Soliman, Tunisia.

Exopolysaccharides (EPS) produced by three Lactic Acid Bacteria strains, SLT10, C7, and B3, were isolated using two methods: ethanol precipitation (EPS-ETOH) and ultrafiltration (EPS-UF) through a 10 KDa cut-off membrane. EPS recovery by ultrafiltration was higher than ethanol precipitation for SLT10 and C7. However, it was similar with both methods for B3. The monomer composition of the EPS fractions revealed differences in structures and molar ratios between the two studied methods. EPS isolated from SLT10 are composed of glucose and mannose for EPS-ETOH against glucose, mannose, and rhamnose for EPS-UF. EPS extracted from C7 and B3 showed similar composition (glucose and mannose) but different molar ratios. The molecular weights of the different EPS fractions ranged from 11.6±1.83 to 62.4±2.94 kDa. Molecular weights of EPS-ETOH fractions were higher than those of EPS-UF fractions. Fourier transform infrared (FTIR) analysis revealed a similarity in the distribution of the functional groups (O-H, C-H, C=O, -COO, and C-O-C) between the EPS isolated from the three strains.
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http://dx.doi.org/10.1155/2018/1896240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6167595PMC
January 2019

Optimization of Hydrothermal and Diluted Acid Pretreatments of Tunisian (L.) Fibers for 2G Bioethanol Production through the Cubic Central Composite Experimental Design CCD: Response Surface Methodology.

Biomed Res Int 2017 24;2017:9524521. Epub 2017 Jan 24.

Laboratory of Microbial Ecology and Technology (LETMi), The National Institute of Applied Sciences and Technology (INSAT), Carthage University, 2 Boulevard de la Terre, BP 676, 1080 Tunis, Tunisia.

This paper opens up a new issue dealing with (LC) lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely, -cellulose (45.80%  ± 1.3), hemicelluloses (20.76%  ± 0.3), and lignins (13.15%  ± 0.6). The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled with . LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%.
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http://dx.doi.org/10.1155/2017/9524521DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5294667PMC
March 2017
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