scholarly journals Effect of acetic acid on fermentation performance of the immobilized yeast Kluyveromyces marxianus on Nypa fruticans leaf sheath pieces

2016 ◽  
Vol 19 (3) ◽  
pp. 165-175
Author(s):  
Quyen Thi Le Vu ◽  
Man Van Viet Le
Keyword(s):  
Acetic Acid ◽  
Ethanol Fermentation ◽  
Acid Content ◽  
Kluyveromyces Marxianus ◽  
Control Sample ◽  
Leaf Sheath ◽  
Yeast Cells ◽  
Immobilized Yeast ◽  
Acetic Acid Content ◽  
Nypa Fruticans

The yeast cells of Kluyveromyces marxianus immobilized on Nypa fruticans leaf sheath pieces was tested for acetic acid tolerance during ethanol fermentation. Control sample with the free yeast cells were also performed under the same conditions. When the acetic acid content in the medium varied from 0 to 8g/L, the cell growth rate of the immobilized and free yeast decreased by 8.3 to 10.3 time, respectively. In addition, increase in acetic acid content from 0 to 8g/L reduced ethanol formation rate of the immobilized and free yeast by 4.1 to 6.8 times, respectively. The immobilized yeast always demonstrated faster sugar assimilation and higher final ethanol concentration than the free yeast. Under acetic acid stress, the fixed yeast exhibited less change in unsaturated degree of fatty acids in cellular membrane than the free yeast. Application of immobilized yeast was therefore potential for improvement in ethanol fermentation from lignocellulosic material.

Continuous ethanol fermentation using immobilized yeast cells

1984 ◽  
Vol 26 (8) ◽  
pp. 992-997 ◽  
Author(s):  
Minoru Nagashima ◽  
Masaki Azuma ◽  
Sadao Noguchi ◽  
Keiichi Inuzuka ◽  
Hirotoshi Samejima
Keyword(s):  
Ethanol Fermentation ◽  
Yeast Cells ◽  
Immobilized Yeast ◽  
Continuous Ethanol Fermentation ◽  
Immobilized Yeast Cells

scholarly journals Effect of Co-Inoculation with Saccharomyces cerevisiae and Lactic Acid Bacteria on the Content of Propan-2-ol, Acetaldehyde and Weak Acids in Fermented Distillery Mashes

2019 ◽  
Vol 20 (7) ◽  
pp. 1659
Author(s):  
Katarzyna Pielech-Przybylska ◽  
Maria Balcerek ◽  
Grzegorz Ciepielowski ◽  
Barbara Pacholczyk-Sienicka ◽  
Łukasz Albrecht ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acid Content ◽  
Isopropyl Alcohol ◽  
Quantitative Composition ◽  
Acetic Acid Content ◽  
Initial Ph

The qualitative and quantitative composition of volatile compounds in fermented distillery mash determines the quality of the obtained distillate of agricultural origin (i.e., raw spirit) and the effectiveness of further purification steps. Propan-2-ol (syn. isopropyl alcohol), due to its low boiling point, is difficult to remove by rectification. Therefore, its synthesis needs to be limited during fermentation by Saccharomyces cerevisiae yeast, while at the same time controlling the levels of acetaldehyde and acetic acid, which are likewise known to determine the quality of raw spirit. Lactic acid bacteria (LAB) are a common but undesirable contaminant in distillery mashes. They are responsible for the production of undesirable compounds, which can affect synthesis of propan-2-ol. Some bacteria strains are able to synthesize isopropyl alcohol. This study therefore set out to investigate whether LAB with S. cerevisiae yeast are responsible for conversion of acetone to propan-2-ol, as well as the effects of the amount of LAB inoculum and fermentation parameters (pH and temperature) on the content of isopropyl alcohol, acetaldehyde, lactic acid and acetic acid in fermented mashes. The results of NMR and comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (GC × GC-TOF MS) analysis confirmed the ability of the yeast and LAB strains to metabolize acetone via its reduction to isopropyl alcohol. Efficient fermentation of distillery mashes was observed in all tested mashes with an initial LAB count of 3.34–6.34 log cfu/mL, which had no significant effect on the ethanol content. However, changes were observed in the contents of by-products. Lowering the initial pH of the mashes to 4.5, without and with LAB (3.34–4.34 log cfu/mL), resulted in a decrease in propan-2-ol and a concomitant increase in acetaldehyde content, while a higher pH (5.0 and 5.5) increased the content of propan-2-ol and decreased acetaldehyde content. Higher temperature (35 °C) promoted propan-2-ol synthesis and also resulted in increased acetic acid content in the fermented mashes compared to the controls. Moreover, the acetic acid content rose with increases in the initial pH and the initial LAB count.

Preparation and Properties of Acidified Prevulcanized Natural Rubber Latex

2014 ◽  
Vol 997 ◽  
pp. 239-242
Author(s):  
Guang Lu ◽  
He Ping Yu ◽  
Yong Zhou Wang ◽  
Yong Yue Luo ◽  
Zong Qiang Zeng
Keyword(s):  
Tensile Strength ◽  
Acetic Acid ◽  
Natural Rubber ◽  
Acid Content ◽  
Natural Rubber Latex ◽  
Rubber Latex ◽  
Elongation At Break ◽  
Acetic Acid Content ◽  
Hot Air ◽  
Aging Resistance

After a maturation of three days at ambient temperature, the sulfur-prevulcanized natural rubber latex (SNRL) was stabilized by 20wt% Peregal O, and then acidified with the 36wt% acetic acid by a ratio of 5, 15, 25, 35 and 45 g of 36wt% acetic acid to 100g SNRL, to obtain acidified prevulcanized NR latex (ASNRL) with different acidity, respectively. The viscosity of ASNRL increased, while the nitrogen content decreased, with the increment of acetic acid content and the decrease in pH; for unaged samples, the tensile strength, elongation at break, 300% and 500% moduli of the ASNRL films were only slightly lower than those of SNRL film; however the hot-air aging resistance decreased with the increment of acetic acid content.

A Novel Immobilization Method of Saccharomyces cerevisiae on Fermentation of Nipa Palm Sap for Fuel Grade Bioethanol Production

2020 ◽  
Vol 849 ◽  
pp. 53-57
Author(s):  
Chairul ◽  
Evelyn ◽  
Syaiful Bahri ◽  
Ella Awaltanova
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Sugar Content ◽  
Yeast Cells ◽  
Eastern Coast ◽  
Bioethanol Production ◽  
Fermentation Time ◽  
Immobilized Yeast ◽  
Immobilized Yeast Cells ◽  
Nipa Palm

Nipa palm (Nypa fruticans) spreads abundantly in the mangrove forests of eastern coast of Sumatera Island, Indonesia. Nipa palm sap can be used as a very high-gravity (VHG) substrate for fermentation. In this research, batch fermentation of nipa sap with initial sugar content of 262.713 mg/ml using immobilized Saccharomyces cerevisiae yeast cells was studied. Immobilization of the yeasts in Na-alginate by droplet method and addition of 0.2% v/v Tween 80 and 0.5g/l ergosterol to the immobilized cells were first carried out. Then, the effect of cells weight percentage (5, 10, 15, and 20% w/v) and fermentation time (24, 36, 48, 60, 72, 84, and 96 hrs) on the bioethanol production were investigated. After, the analysis of bioethanol concentration was investigated using Gas Chromatography. The bioethanol production increased with the fermentation time until reaching a maximum value at all cell weights. Except with the 20% w/v, this peak was followed by a decrease in the bioethanol production at cell weights of 5, 10, and 15% w/v. This phenomenon may be explained by degradation of bioethanol into acetic acid resulting in the decreased concentration at the end of fermentation. The formation of acetic acid was characterized by decreases in the pH values of the fermentation medium. On the contrary, the bioethanol level tended to increase until the end of fermentation with the immobilized yeast cells of 20% w/v. High number of available immobilized yeast cells at the end of fermentation, accumulation of bioethanol produced at earlier times, and no further conversion of bioethanol to acetic acid could be the reasons for this increase. The optimum conditions for bioethanol production were 20% w/v cell weight and 96 hr fermentation time, at bioethanol concentration of 17.57% v/v.

Enantioselective analysis of naproxen using chiral molecular imprinting polymers based thin-layer chromatography

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Fengyun Huangfu ◽  
Bing Wang ◽  
Juanjuan Shan ◽  
Zhiliang Zhang
Keyword(s):  
Particle Size ◽  
Acetic Acid ◽  
Particle Size Distribution ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Size Distribution ◽  
Acid Content ◽  
Rational Design ◽  
Acetic Acid Content ◽  
Layer Chromatography

Abstract This paper describes a rational design and testing of molecularly imprinted polymers (MIPs) as chiral stationary phases of thin-layer chromatography (TLC) for enantiomeric purity of naproxen. Using D-naproxen as template, MIPs with particle size between 10~90 μm were prepared by precipitation polymerization in acetonitrile/methanol mixed solvent. The interactions between functional monomers and template were verified by UV absorption spectrometry. The morphology, particle size distribution and specific surface area of MIPs were also observed by scanning electron microscopy, particle size distribution meter and liquid nitrogen adsorption instrument, respectively. Binding capacities of MIPs had been studied by equilibrium binding assay. Preparation conditions of TLC and impact of acetic acid content on the separation of enantiomers were investigated. The results indicated that when acetic acid content was 4%, the racemates of templates were completely separated, and the chiral separation factor α was 1.58.

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