scholarly journals Optimization of Synthetic Media Composition for Kluyveromyces marxianus Fed-Batch Cultivation

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 62
Author(s):  
Konstantins Dubencovs ◽  
Janis Liepins ◽  
Arturs Suleiko ◽  
Anastasija Suleiko ◽  
Reinis Vangravs ◽  
...  

The Kluyveromyces marxianus yeast recently has gained considerable attention due to its applicability in high-value-added product manufacturing. In order to intensify the biosynthesis rate of a target product, reaching high biomass concentrations in the reaction medium is mandatory. Fed-batch processes are an attractive and efficient way how to achieve high cell densities. However, depending on the physiology of the particular microbial strain, an optimal media composition should be used to avoid by-product synthesis and, subsequently, a decrease in overall process effi-ciency. Thus, the aim of the present study was to optimise the synthetic growth medium and feeding solution compositions (in terms of carbon, nitrogen, phosphorous, magnesium, and calcium concentrations) for high cell density K. marxianus fed‑batch cultivations. Additionally, the biomass yields from the vitamin mixture and other macro/microelements were identified. A model predictive control algorithm was successfully applied for a fed-batch cultivation control. Biomass growth and substrate consumption kinetics were compared with the mathematical model predictions. Finally, 2‑phenylethanol biosynthesis was induced and its productivity was estimated. The determined optimal macronutrient ratio for K. marxianus biomass growth was identified as C:N:P = 1:0.07:0.011. The maximal attained yeast biomass concentration was close to 70 g·L-1 and the 2-PE biosynthesis rate was 0.372 g·L−1·h−1, with a yield of 74% from 2-phenylalanine.

2018 ◽  
Vol 6 (4) ◽  
pp. 1162-1169 ◽  
Author(s):  
Zhijiang Li ◽  
Yanan Zhou ◽  
Hongzhi Yang ◽  
Dongjie Zhang ◽  
Chengtao Wang ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Tong Shen ◽  
Qing Liu ◽  
Xixian Xie ◽  
Qingyang Xu ◽  
Ning Chen

Intracellular precursor supply is a critical factor for amino acid productivity. In the present study,ppsAandtktAgenes were overexpressed in genetically engineeredEscherichia colito enhance the availability of two precursor substrates, phosphoenolpyruvate and erythrose-4-phosphate. The engineered strain, TRTH0709 carrying pSV709, produced 35.9 g/L tryptophan from glucose after 40 h in fed-batch cultivation. The two genes were inserted, independently or together, into a low-copy-number expression vector (pSTV28) and transferred to TRTH0709. Fed-batch fermentations at high cell densities of the recombination strains revealed that overexpression of theppsAgene alone does not significantly increase tryptophan yield. On the other hand, overexpression of thetktAgene, alone or with theppsAgene, could further improve tryptophan yield to a final tryptophan titer of 37.9 and 40.2 g/L, respectively. These results represent a 5.6% and 11.9% enhancement over the titer achieved by TRTH0709. No evident genetic modifications leading to growth impairment were observed.


2003 ◽  
Vol 27 (1) ◽  
pp. 175-181 ◽  
Author(s):  
Marianne H Thuesen ◽  
Allan Nørgaard ◽  
Anne M Hansen ◽  
Mikael B Caspersen ◽  
Hans E.M Christensen

2004 ◽  
Vol 26 (3) ◽  
pp. 147-150 ◽  
Author(s):  
Beom Soo Kim ◽  
Seung Chul Lee ◽  
Sang Yup Lee ◽  
Yong Keun Chang ◽  
Ho Nam Chang

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