scholarly journals Redirection of the central metabolism of Klebsiella pneumoniae towards dihydroxyacetone production

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Shaoqi Sun ◽  
Yike Wang ◽  
Lin Shu ◽  
Xiyang Lu ◽  
Qinghui Wang ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Triosephosphate Isomerase ◽  
Product Formation ◽  
Dihydroxyacetone Phosphate ◽  
Optimal Conditions ◽  
Glycerol Production ◽  
Fed Batch ◽  
Total Conversion ◽  
Fed Batch Fermentation ◽  
Catabolism Pathway

Abstract Background Klebsiella pneumoniae is a bacterium that can be used as producer for numerous chemicals. Glycerol can be catabolised by K. pneumoniae and dihydroxyacetone is an intermediate of this catabolism pathway. Here dihydroxyacetone and glycerol were produced from glucose by this bacterium based a redirected glycerol catabolism pathway. Results tpiA, encoding triosephosphate isomerase, was knocked out to block the further catabolism of dihydroxyacetone phosphate in the glycolysis. After overexpression of a Corynebacterium glutamicum dihydroxyacetone phosphate dephosphorylase (hdpA), the engineered strain produced remarkable levels of dihydroxyacetone (7.0 g/L) and glycerol (2.5 g/L) from glucose. Further increase in product formation were obtained by knocking out gapA encoding an iosenzyme of glyceraldehyde 3-phosphate dehydrogenase. There are two dihydroxyacetone kinases in K. pneumoniae. They were both disrupted to prevent an inefficient reaction cycle between dihydroxyacetone phosphate and dihydroxyacetone, and the resulting strains had a distinct improvement in dihydroxyacetone and glycerol production. pH 6.0 and low air supplement were identified as the optimal conditions for dihydroxyacetone and glycerol production by K, pneumoniae ΔtpiA-ΔDHAK-hdpA. In fed batch fermentation 23.9 g/L of dihydroxyacetone and 10.8 g/L of glycerol were produced after 91 h of cultivation, with the total conversion ratio of 0.97 mol/mol glucose. Conclusions This study provides a novel and highly efficient way of dihydroxyacetone and glycerol production from glucose.

scholarly journals Reverse glycerol catabolism pathway for dihydroxyacetone and glycerol production by Klebsiella pneumoniae

2021 ◽  
Author(s):  
Shaoqi Sun ◽  
Yike Wang ◽  
Lin Shu ◽  
Xiyang Lu ◽  
Qinghui Wang ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Triosephosphate Isomerase ◽  
Product Formation ◽  
Dihydroxyacetone Phosphate ◽  
Glycerol Production ◽  
Fed Batch ◽  
Total Conversion ◽  
Engineering Strain ◽  
Fed Batch Fermentation ◽  
Catabolism Pathway

Abstract Background: Klebsiella pneumoniae is a bacterium that can be used as producer for numerous chemicals. Glycerol can be catabolised by K. pneumoniae and dihydroxyacetone is an intermediate of this catabolism pathway. Here dihydroxyacetone and glycerol were produced from glucose by this bacterium based on a reverse glycerol catabolism pathway. Results: tpiA, encoding triosephosphate isomerase, was knocked out to block the further catabolism of dihydroxyacetone phosphate in the glycolysis. After overexpression of a Corynebacterium glutamicum dihydroxyacetone phosphate dephosphorylase (hdpA), the engineering strain produced remarkable levels of dihydroxyacetone and glycerol from glucose. Further increase in product formation were obtained by knocking out gapA encoding an iosenzyme of glyceraldehyde 3-phosphate dehydrogenase. There are two dihydroxyacetone kinases in K. pneumoniae. They were both disrupted to prevent an inefficient reaction cycle between dihydroxyacetone phosphate and dihydroxyacetone, and the resulting strains had a distinct improvement in dihydroxyacetone and glycerol production. pH 6.0 and low air supplement were identified as the optimal conditions for dihydroxyacetone and glycerol production by K, pneumoniae ΔtpiA-ΔDHAK-hdpA. In fed batch fermentation 23.9 g/L of dihydroxyacetone and 10.8 g/L of glycerol were produced after 91 hours of cultivation, with the total conversion ratio of 0.97 mol/mol glucose.Conclusions: This study provides a novel and highly efficient way of dihydroxyacetone and glycerol production from glucose.

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.

Improved production of 1,3-propanediol from biodiesel-derived crude glycerol by Klebsiella pneumoniae in fed-batch fermentation

2018 ◽  
Vol 349 ◽  
pp. 25-36 ◽  
Author(s):  
Xiaoguang Yang ◽  
Han Suk Choi ◽  
Ju Hun Lee ◽  
Soo Kwon Lee ◽  
Sung Ok Han ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Batch Fermentation ◽  
Crude Glycerol ◽  
Fed Batch ◽  
Fed Batch Fermentation

scholarly journals NaOH-Catalyzed Fractionation of Rice Husk Followed by Concomitant Production of Bioethanol and Furfural for Improving Profitability in Biorefinery

2021 ◽  
Vol 11 (16) ◽  
pp. 7508
Author(s):  
Hyun Jin Jung ◽  
Kyeong Keun Oh
Keyword(s):  
Rice Husk ◽  
Removal Rate ◽  
Enzymatic Saccharification ◽  
High Yield ◽  
Optimal Conditions ◽  
Essential Factor ◽  
Fed Batch ◽  
Fed Batch Fermentation ◽  
High Ethanol ◽  
Furfural Production

The alkaline fractionation of rice husk (RH) with NaOH was optimized for the purpose of obtaining a high-yield recovery of glucan and increasing the removal rate for lignin and ash, resulting in a hemicellulose-rich hydrolysate. The determined optimal conditions were a temperature of 150 °C, reaction time of 45 min, and NaOH concentration of 6% (w/v). The glucan content in the fractionated RH (Fr. RH) was 80.1%, which was significantly increased compared to the raw RH (35.6%). High glucan content in the fractionated solid residue is the most essential factor for minimizing enzyme dosages in enzymatic saccharification. The final enzymatic digestibilities (at 96 h) of raw and NaOH-Fr. RH with cellulase loadings of 30 FPU/g cellulose were 10.5% and 81.3%, respectively. Approximately 71.6% of the xmg content (mainly xylose) was concomitantly degraded into the fractionated hydrolysate (Fr. Hydrolysate). When this hydrolysate was acidified with sulfuric acid and subjected to heat treatment, a furfural production yield of about 64.9% was obtained. The results show that two-stage fed-batch fermentation with glucan-rich Fr. RH has the potential to achieve high-ethanol titers of 28.7 g/L.

Glycerol Synthesis Attenuation ofCandida glycerinogenesin Fed-batch Fermentation

2012 ◽  
Vol 18 (5) ◽  
pp. 791
Author(s):  
Xiaoyun DING ◽  
Bin ZHUGE ◽  
Huiying FANG ◽  
Hong ZONG ◽  
Xiaoxiao LIU ◽  
...  
Keyword(s):  
Batch Fermentation ◽  
Fed Batch ◽  
Fed Batch Fermentation ◽  
Glycerol Synthesis
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