Fermentation characteristics of l-tryptophan production by thermoacidophilic Bacillus acidocaldarius in a defined medium

Kocabaş, Pınar; Çalı́k, Pınar; Özdamar, Tunçer H.

doi:10.1016/j.enzmictec.2006.02.012

Cited by 23 publications

(8 citation statements)

References 23 publications

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“…But with the increase of the agitation, q O 2 decreases and the lines have lower slopes. A similar influence of stirrer speed on specific oxygen uptake rates has been reported for other microbial systems (Calik et al, 2004;Calik et al, 2006;Kocabas et al, 2006).…”

Section: Oxygen Mass Transfer and Oxygen Uptake Ratessupporting

confidence: 60%

Specific oxygen uptake rate as indicator of cell response of Rhodococcus erythropolis cultures to shear effects

Garcı́a-Ochoa

Escobar

Gómez

2015

Chemical Engineering Science

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Section: Oxygen Mass Transfer and Oxygen Uptake Ratessupporting

confidence: 60%

Specific oxygen uptake rate as indicator of cell response of Rhodococcus erythropolis cultures to shear effects

Garcı́a-Ochoa

Escobar

Gómez

2015

Chemical Engineering Science

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“…L‐tryptophan is an essential amino acid in the diet of humans and animals, and is widely used in food and animal feed (Dodge & Gerstner, ). It is also considered as a key precursor in industrial and pharmaceutical compounds such as melatonin, niacin, and serotonin (Kocabaş, Çalık, & Özdamar, ). At present, the industrial scale production of L‐tryptophan is through microbial fermentation, in particular Corynebacterium glutamicum and Escherichia coli ( E. coli ), by using sustainable feedstocks including glucose and other renewable carbohydrates (Liu, Cheng, Xie, Xu, & Chen, ; Zhao et al, ).…”

Section: Introductionmentioning

confidence: 99%

Overproduction of L‐tryptophan via simultaneous feed of glucose and anthranilic acid from recombinant Escherichia coli W3110: Kinetic modeling and process scale‐up

Jing

Tang

Yao

et al. 2017

Biotech & Bioengineering

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L-tryptophan is an essential amino acid widely used in food and pharmaceutical industries. However, its production via Escherichia coli fermentation suffers severely from both low glucose conversion efficiency and acetic acid inhibition, and to date effective process control methods have rarely been explored to facilitate its industrial scale production. To resolve these challenges, in the current research an engineered strain of E. coli was used to overproduce L-tryptophan. To achieve this, a novel dynamic control strategy which incorporates an optimized anthranilic acid feeding into a dissolved oxygen-stat (DO-stat) glucose feeding framework was proposed for the first time. Three original contributions were observed. Firstly, compared to previous DO control methods, the current strategy was able to inhibit completely the production of acetic acid, and its glucose to L-tryptophan yield reached 0.211 g/g, 62.3% higher than the previously reported. Secondly, a rigorous kinetic model was constructed to simulate the underlying biochemical process and identify the effect of anthranilic acid on both glucose conversion and L-tryptophan synthesis. Finally, a thorough investigation was conducted to testify the capability of both the kinetic model and the novel control strategy for process scale-up. It was found that the model possesses great predictive power, and the presented strategy achieved the highest glucose to L-tryptophan yield (0.224 g/g) ever reported in large scale processes, which approaches the theoretical maximum yield of 0.227 g/g. This research, therefore, paves the way to significantly enhance the profitability of the investigated bioprocess.

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“…In Equation (1), X is dry biomass concentration (g/L), t is duration time since inoculation (h) and stoichiometric coefficients α and β represent cell metabolism of oxygen consumption, where α describes the cell's oxygen consumption yield for biomass growth (α ≡ Y o 2 /X , [ g(O 2 )/g(X)]) and β describes the cell's oxygen consumption for maintenance (β ≡ m O 2 /X , [g(O 2 )/g(X)/h]) [16][17][18]. Çalik [19], studying the effects of pH on benzaldehyde lyase production by Escherichia coli, and Kocabaş [20], studying l-tryptophan production, clarified that oxygen consumption consisted of three parts: Cell growth, maintenance, and byproduct formation. In order to enable model fitting of protein and biomass concentration, this study suggests modifying the Luedeking-Piret model in Equation (1) by adding parameter γ, which represents the oxygen consumption yield for protein synthesis rate P (t) (γ ≡ Y o 2 /p ) [4,21]:…”

Section: Basis Of Biomass and Product Model Fittingmentioning

confidence: 99%

Identification of Functional Bioprocess Model for Recombinant E. Coli Cultivation Process

Urniezius

Survyla

2019

Entropy

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The purpose of this study is to introduce an improved Luedeking–Piret model that represents a structurally simple biomass concentration approach. The developed routine provides acceptable accuracy when fitting experimental data that incorporate the target protein concentration of Escherichia coli culture BL21 (DE3) pET28a in fed-batch processes. This paper presents system identification, biomass, and product parameter fitting routines, starting from their roots of origin to the entropy-related development, characterized by robustness and simplicity. A single tuning coefficient allows for the selection of an optimization criterion that serves equally well for higher and lower biomass concentrations. The idea of the paper is to demonstrate that the use of fundamental knowledge can make the general model more common for technological use compared to a sophisticated artificial neural network. Experimental validation of the proposed model involved data analysis of six cultivation experiments compared to 19 experiments used for model fitting and parameter estimation.

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Fermentation characteristics of l-tryptophan production by thermoacidophilic Bacillus acidocaldarius in a defined medium

Cited by 23 publications

References 23 publications

Specific oxygen uptake rate as indicator of cell response of Rhodococcus erythropolis cultures to shear effects

Specific oxygen uptake rate as indicator of cell response of Rhodococcus erythropolis cultures to shear effects

Overproduction of L‐tryptophan via simultaneous feed of glucose and anthranilic acid from recombinant Escherichia coli W3110: Kinetic modeling and process scale‐up

Identification of Functional Bioprocess Model for Recombinant E. Coli Cultivation Process

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