The pH mediated effects of initial glucose concentration on the transitory occurrence of extracellular metabolites, gas exchange and growth yields of aerobic batch cultures ofKlebsiella pneumoniae

1987 ◽  
Vol 30 (3) ◽  
pp. 352-362 ◽  
Author(s):  
J. J. L�nsmann Iversen
Keyword(s):  
Gas Exchange ◽  
Glucose Concentration ◽  
Growth Yields ◽  
Initial Glucose Concentration ◽  
Batch Cultures ◽  
Mediated Effects ◽  
Extracellular Metabolites

scholarly journals Reaction Kinetics of Levulinic Acid Synthesis from Glucose Using Bronsted Acid Catalyst

2021 ◽  
Author(s):  
Meutia Ermina Toif ◽  
Muslikhin Hidayat ◽  
Rochmadi Rochmadi ◽  
Arief Budiman
Keyword(s):  
Reaction Kinetics ◽  
Glucose Concentration ◽  
Levulinic Acid ◽  
Acid Catalyst ◽  
Operating Conditions ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Initial Glucose Concentration ◽  
Brönsted Acid ◽  
Kinetics Of

Abstract Glucose is the primary derivative of lignocellulosic biomass, which is abundantly available. Glucose has excellent potential to be converted into valuable compounds such as ethanol, sorbitol, gluconic acid, and levulinic acid (LA). Levulinic acid is a very promising green platform chemical. It is composed of two functional groups, ketone and carboxylate groups which can act as highly reactive electrophiles for nucleophilic attack so it has extensive applications, including fuel additives, raw materials for the pharmaceutical industry, and cosmetics. The reaction kinetics of LA synthesis from glucose using hydrochloric acid catalyst (bronsted acid) were studied in a wide range of operating conditions, i.e., temperature of 140-180 oC, catalyst concentration of 0.5-1.5 M, and initial glucose concentration of 0.1-0.5 M. The highest LA yield is 48.34 %wt at 0.1 M initial glucose concentration, 1 M HCl, and temperature of 180 oC. The experimental results show that the bronsted acid catalyst's reaction pathway consists of glucose decomposition to levoglucosan (LG), conversion of LG to 5-hydroxymethylfurfural (HMF), and rehydration of HMF to LA. The experimental data yields a good fitting by assuming a first-order reaction model.

scholarly journals Kinetic Constant Variability in Bacterial Oxidation of Elemental Sulfur

2007 ◽  
Vol 73 (11) ◽  
pp. 3752-3754 ◽  
Author(s):  
Blanka Pokorna ◽  
Martin Mandl ◽  
Sarka Borilova ◽  
Pavla Ceskova ◽  
Romana Markova ◽  
...  
Keyword(s):  
Acidithiobacillus Ferrooxidans ◽  
Elemental Sulfur ◽  
Kinetic Constant ◽  
Sulfur Oxidation ◽  
Growth Yields ◽  
Resting Cells ◽  
Michaelis Constant ◽  
Bacterial Oxidation ◽  
Batch Cultures ◽  
Oxidation Rates

ABSTRACT Wide ranges of growth yields on sulfur (from 2.4 × 1010 to 8.1 × 1011 cells g−1) and maximum sulfur oxidation rates (from 0.068 to 1.30 mmol liter−1 h−1) of an Acidithiobacillus ferrooxidans strain (CCM 4253) were observed in 73 batch cultures. No significant correlation between the constants was observed. Changes of the Michaelis constant for sulfur (from 0.46 to 15.5 mM) in resting cells were also noted.

Effect of Reaction Parameters on the Production of Ethyl Levulinate from Glucose in Ethanol

2012 ◽  
Vol 512-515 ◽  
pp. 388-391 ◽  
Author(s):  
Chun Chang ◽  
Xiao Xian Jiang ◽  
Ting Zhang ◽  
Bo Li
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Glucose Concentration ◽  
Sulfuric Acid Concentration ◽  
Ethanol Conversion ◽  
Reaction Parameters ◽  
Water Addition ◽  
Initial Glucose Concentration ◽  
Ethyl Levulinate ◽  
Higher Temperature

In order to explore the forming rules of ethyl levulinate from glucose in ethanol, several reaction parameters including the initial glucose concentration (10~30 g/L), sulfuric acid concentration (0.1~2 wt%), temperature (170~200 °C) and water addition were investigate, respectively. In addition, effect of the acid concentration on ethanol conversion was also studied. The results show that lower initial glucose concentration is helpful to improve the ethyl levulinate yield, and higher acid concentration can improve the conversion of glucose to ethyl levulinate, which also can improve the condensation of the ethanol. However, higher temperature is unfavorable for the increase of ethyl levulinate yield, and the ethyl levulinate decreased significantly with the increase of water addition.

scholarly journals Molar Growth Yields and Fermentation Balances of Lactobacillus casei L3 in Batch Cultures and in Continuous Cultures

1970 ◽  
Vol 63 (3) ◽  
pp. 333-345 ◽  
Author(s):  
W. De Vries ◽  
W. M. C. Kapteijn ◽  
E. G. Van Der Beek ◽  
A. H. Stouthamer
Keyword(s):  
Lactobacillus Casei ◽  
Growth Yields ◽  
Continuous Cultures ◽  
Batch Cultures

Monitoring Initial Glucose Concentration for Optimum pH Control during Fermentation of Microbial Cellulose in Rotary Discs Reactor

2013 ◽  
Vol 594-595 ◽  
pp. 319-324 ◽  
Author(s):  
Khairul Azly Zahan ◽  
Norhayati Pa’e ◽  
Kok Fook Seng ◽  
Ida Idayu Muhamad
Keyword(s):  
Glucose Concentration ◽  
Ph Control ◽  
Fermentation Medium ◽  
Initial Glucose Concentration ◽  
Cellulose Production ◽  
Microbial Cellulose ◽  
Cellulose Yield ◽  
Optimum Ph ◽  
Initial Ph ◽  
Wet Weight

The study aimed to investigate the effect of initial glucose concentration on the microbial cellulose production using Acetobacter xylinum in a Rotary Discs Reactor (RDR-2 liter volume). The fermentations were carried out for four days at temperature 28°C, initial pH 6.5, and 9 rpm of rotation speed; meanwhile, the initial glucose concentration was manipulated in the range of 0.5-5.0 % (w/v). The cell growth was stimulated using 1.4% (v/v) ethanol in the fermentation medium. The result indicated that 1% (w/v) of initial glucose concentration provided the highest microbial cellulose yield with total wet weight of 296.1657g/l. The increase of initial glucose concentration resulted to the decrease of microbial cellulose yield and greater pH drop after fermentation. It can be conclude that production of microbial cellulose using RDR could produce relatively much higher microbial cellulose with less amounts of glucose in a shorter fermentation period compared to static fermentation due to more efficient oxygen uptake during rotary movements and homogenous environment for microbial growth.

scholarly journals Reaction Kinetics of Levulinic Acid Synthesis from Glucose Using Bronsted Acid Catalyst

2021 ◽  
Vol 16 (4) ◽  
pp. 904-915
Author(s):  
Meutia Ermina Toif ◽  
Muslikhin Hidayat ◽  
Rochmadi Rochmadi ◽  
Arief Budiman
Keyword(s):  
Reaction Kinetics ◽  
Glucose Concentration ◽  
Levulinic Acid ◽  
Operating Conditions ◽  
Nucleophilic Attack ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Initial Glucose Concentration ◽  
Brönsted Acid ◽  
Kinetics Of

Glucose is one of the primary derivative products from lignocellulosic biomass, which is abundantly available. Glucose has excellent potential to be converted into valuable compounds such as ethanol, sorbitol, gluconic acid, and levulinic acid (LA). Levulinic acid is an exceptionally promising green platform chemical. It comprises two functional groups, ketone and carboxylate, acting as highly reactive electrophiles for a nucleophilic attack. Therefore, it has extensive applications, including fuel additives, raw materials for the pharmaceutical industry, and cosmetics. This study reports the reaction kinetics of LA synthesis from glucose catalyzed by hydrochloric acid (HCl), a Bronsted acid, that was carried out under a wide range of operating conditions; i.e. the temperature of 140–180 °C, catalyst concentration of 0.5–1.5 M, and initial glucose concentration of 0.1–0.5 M. The highest LA yield of 48.34 % was able to be obtained from an initial glucose concentration of 0.1 M and by using 1 M HCl at 180 °C. The experimental results show that the Bronsted acid-catalyzed reaction pathway consists of glucose decomposition to levoglucosan (LG), conversion of LG to 5-hydroxymethylfurfural (HMF), and rehydration of HMF to LA. The experimental data yields a good fitting by assuming a first-order reaction model. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

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