scholarly journals Kinetic Studies on Fermentative Production of Biofuel from Synthesis Gas UsingClostridium ljungdahlii

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Maedeh Mohammadi ◽  
Abdul Rahman Mohamed ◽  
Ghasem D. Najafpour ◽  
Habibollah Younesi ◽  
Mohamad Hekarl Uzir
Keyword(s):  
Cell Growth ◽  
Synthesis Gas ◽  
Uptake Rate ◽  
Kinetic Studies ◽  
Product Formation ◽  
Volterra Model ◽  
Substrate Uptake ◽  
Growth Substrate ◽  
Clostridium Ljungdahlii ◽  
Batch Bioreactors

The intrinsic growth, substrate uptake, and product formation biokinetic parameters were obtained for the anaerobic bacterium,Clostridium ljungdahlii, grown on synthesis gas in various pressurized batch bioreactors. A dual-substrate growth kinetic model using Luong for CO and Monod for H2was used to describe the growth kinetics of the bacterium on these substrates. The maximum specific growth rate (μmax= 0.195 h−1) and Monod constants for CO (Ks,CO= 0.855 atm) and H2(Ks,H2= 0.412 atm) were obtained. This model also accommodated the CO inhibitory effects on cell growth at high CO partial pressures, where no growth was apparent at high dissolved CO tensions (PCO∗>0.743 atm). The Volterra model, Andrews, and modified Gompertz were, respectively, adopted to describe the cell growth, substrate uptake rate, and product formation. The maximum specific CO uptake rate (qmax= 34.364 mmol/gcell/h), CO inhibition constant (KI= 0.601 atm), and maximum rate of ethanol (Rmax= 0.172 mmol/L/h atPCO= 0.598 atm) and acetate (Rmax= 0.096 mmol/L/h atPCO= 0.539 atm) production were determined from the applied models.

scholarly journals Application Of The Z And Laplace Transforms To Panification Yeast Production Using An Airlift Bioreactor

2020 ◽  
Author(s):  
Arnaldo Silva Oliveira ◽  
Juan C. B. Neto ◽  
Igor J. B. Santos ◽  
Edson R. Nucci
Keyword(s):  
Cell Growth ◽  
Product Formation ◽  
Laplace Transforms ◽  
Discrete Models ◽  
Average Error ◽  
Growth Substrate ◽  
Substrate Consumption ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mathematical Techniques ◽  
Discrete Time Models

Abstract The Z- and Laplace transforms are mathematical techniques applied to solve difference equations and differential equations, respectively. Mathematical models used to describe cell growth, substrate consumption and product formation in bioprocesses can be represented by these types of equations. Thus, in this work, the fermentation process of the yeast Saccharomyces cerevisiae was modeled using different models from the literature, and the Z- and Laplace transforms were applied to solve the equations. Once the equations were solved, the models were represented in state space and simulated in Octave® software. Finally, the models were compared to experimental data from previous studies and to each other. Verhulst was the model that best described the process, with an average error of 4.74% for cell growth and 13.9% for substrate consumption. This work is unprecedented since no works that use the Z transform and discrete models for the representation of fermentation of this yeast were found in the literature. Even more importantly, this work proved that discrete-time models can be applied to bioprocesses with the same precision as continuous-time models.

Effect of Medium Composition and Kinetic Studies on Extracellular and Intracellular Production of L-asparaginase from Pectobacterium carotovorum

2010 ◽  
Vol 16 (2) ◽  
pp. 115-125 ◽  
Author(s):  
S. Arrivukkarasan ◽  
M. Muthusivaramapandian ◽  
R. Aravindan ◽  
T. Viruthagiri
Keyword(s):  
Cell Growth ◽  
Monosodium Glutamate ◽  
Kinetic Studies ◽  
Product Formation ◽  
Medium Composition ◽  
Coefficient Of Determination ◽  
Logarithmic Phase ◽  
Pectobacterium Carotovorum ◽  
Medium Components ◽  
Asparaginase Activity

Microbial L-asparaginase occupies a prominent place among biocatalysts owing to their ability to catalyze the reaction that hydrolyze the asparagine molecule. Effect of various medium components on the production of L-asparaginase in submerged fermentation by Pectobacterium carotovorum was studied for optimal nutrient requirements. Six different media compositions were tested for the L-asparaginase production keeping fermentation conditions constant at temperature 30 °C, initial pH 7.0 and agitation speed of 120 rpm. Maximum intracellular and extracellular L-asparaginase activity was obtained in the medium containing tryptone, yeast extract, monosodium glutamate, K2HPO4 and L-asparagine. These medium components were further optimized by central composite experimental design using response surface methodology. Maximum intracellular and extracellular L-asparaginase activity of 2.282 U/mL and 0.587 U/mL were obtained respectively at the late logarithmic phase in optimized media. Unstructured kinetic models were used to describe the cell growth and product formation kinetics. The unstructured models predicted the cell growth and product formation profile accurately with high coefficient of determination.

Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

2003 ◽  
Vol 3 (1-2) ◽  
pp. 201-207
Author(s):  
H. Nagaoka ◽  
T. Nakano ◽  
D. Akimoto
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Turbulence Model ◽  
Uptake Rate ◽  
Oscillatory Flow ◽  
Substrate Uptake ◽  
Flow Conditions ◽  
Mass Transfer Mechanism ◽  
Substrate Uptake Rate ◽  
Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

scholarly journals Side-by-Side Comparison of Clean and Biomass-Derived, Impurity-Containing Syngas as Substrate for Acetogenic Fermentation with Clostridium ljungdahlii

Fermentation ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 84
Author(s):  
Alba Infantes ◽  
Michaela Kugel ◽  
Klaus Raffelt ◽  
Anke Neumann
Keyword(s):  
Biomass Gasification ◽  
Product Formation ◽  
Inhibitory Effects ◽  
Fed Batch ◽  
Gaseous Mixtures ◽  
Clostridium Ljungdahlii ◽  
Acetogenic Bacteria ◽  
Fed Batch Fermentation ◽  
Total Productivity ◽  
The Impact

Syngas, the product of biomass gasification, can play an important role in moving towards the production of renewable chemical commodities, by using acetogenic bacteria to ferment those gaseous mixtures. Due to the complex and changing nature of biomass, the composition and the impurities present in the final biomass-derived syngas will vary. Because of this, it is important to assess the impact of these factors on the fermentation outcome, in terms of yields, productivity, and product formation and ratio. In this study, Clostridium ljungdahlii was used in a fed-batch fermentation system to analyze the effect of three different biomass-derived syngases, and to compare them to equivalent, clean syngas mixtures. Additionally, four other clean syngas mixtures were used, and the effects on product ratio, productivity, yield, and growth were documented. All biomass-derived syngases were suitable to be used as substrates, without experiencing any complete inhibitory effects. From the obtained results, it is clear that the type of syngas, biomass-derived or clean, had the greatest impact on product formation ratios, with all biomass-derived syngases producing more ethanol, albeit with lesser total productivity.

Sublethal acid stress and uncoupling effects on cell growth and product formation in Xanthomonas campestris cultures

2002 ◽  
Vol 12 (3) ◽  
pp. 181-192 ◽  
Author(s):  
M.Eugénia Esgalhado ◽  
Ana Teresa Caldeira ◽  
J.Carlos Roseiro ◽  
A.Nick Emery
Keyword(s):  
Cell Growth ◽  
Xanthomonas Campestris ◽  
Acid Stress ◽  
Product Formation
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