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.

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 Impact of acetolactate synthase inactivation on 1,3-propanediol fermentation byKlebsiella pneumoniae

2018 ◽  
Author(s):  
Sheng Zhou ◽  
Youhua Huang ◽  
Xinliang Mao ◽  
Lili Li ◽  
Chuanyu Guo ◽  
...  
Keyword(s):  
Metabolic Flux ◽  
Wild Type Strain ◽  
Lactate Production ◽  
Acetolactate Synthase ◽  
Gene Replacement ◽  
Wild Type ◽  
Fed Batch ◽  
Formation Pathway ◽  
Fed Batch Fermentation ◽  
The Impact

Abstract1,3-Propanediol (1,3-PDO) is an important compound that is mainly used in industry for polymer production. Fermentation of 1,3-PDO from glycerol by marineKlebsiella pneumoniaeis accompanied by formation of 2,3-butanediol (2,3-BDO) as one of the main byproduct. The first step in the formation of 2,3-BDO from pyruvate is catalyzed by acetolactate synthase (ALS), an enzyme that competes with 1,3-PDO oxidoreductase for the cofactor NADH. This study aimed to analyze the impact of engineering the 2,3-BDO formation pathway via inactivation of ALS on 1,3-PDO fermentation by marineK. pneumoniaeHSL4. An ALS mutant was generated using Red recombinase assisted gene replacement. The ALS specific activities ofK. pneumoniaeΔALS were notably lower than that of the wild-type strain. Fed-batch fermentation of the mutant strain resulted in a 1,3-PDO concentration, productivity and conversion of 72.04 g L−1, 2.25 g L−1h−1, and 0.41 g g−1, a slightly increase compared with the parent strain. Moreover, inactivation of ALS decreasedmeso-2,3-BDO formation to trace amounts, significantly increased 2S,3S-BDO and lactate production, and a pronounced redistribution of intracellular metabolic flux was apparent.

scholarly journals Effect of Cysteine, Yeast Extract, pH Regulation and Gas Flow on Acetate and Ethanol Formation and Growth Profiles of Clostridium ljungdahlii Syngas Fermentation

2020 ◽  
Author(s):  
Alba Infantes ◽  
Michaela Kugel ◽  
Anke Neumann
Keyword(s):  
Yeast Extract ◽  
Metabolic Regulation ◽  
Gas Flow ◽  
Product Formation ◽  
Fermentation Products ◽  
Clostridium Ljungdahlii ◽  
Lower Productivity ◽  
Acetogenic Bacteria ◽  
Gas Consumption ◽  
Growth Product

ABSTRACTThe fermentation of synthesis gas, or syngas, which consists mainly of CO, CO2 and H2 by acetogenic bacteria has the potential to help in transitioning from a fossil-fuel-based to a renewable bio-economy. Clostridium ljungdahlii, one of such microorganisms, has as main fermentation products acetate and ethanol. Multiple research efforts have been directed towards understanding how the metabolism and the product formation of this, and other acetogenic bacteria, can be directed towards increasing productivities and yields; nonetheless, transferring those findings to a particular set-up can prove challenging. This study used a well-established and robust fed-batch fermentation system with C. ljungdahlii to look into the effects of different fermentation pH profiles, gas flow, and the supplementation with additional yeast extract or cysteine on growth, product formation ratios, yields, and productivities, as well as gas consumption. Neither yeast extract nor cysteine supplementation had a noticeable impact on cell growth, product formation or overall gas consumption. The lowering of the pH proved mainly detrimental, with decreased productivities and no improvement in ethanol ratios. The most notable shift towards ethanol was achieved by the combination of lowering both the pH and the gas flow after 24 h, but with the caveat of lower productivity. The obtained results, unexpected to some extent, highlight the necessity for a better understanding of the physiology and the metabolic regulation of acetogenic bacteria in order for this process to become more industrially relevant.

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.

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

The Impact of Biochar on the Soil

2018 ◽  
Vol 69 (8) ◽  
pp. 2197-2208
Author(s):  
Carmen Otilia Rusanescu ◽  
Erol Murad ◽  
Cosmin Jinescu ◽  
Marin Rusanescu
Keyword(s):  
Agricultural Land ◽  
Agricultural Soils ◽  
Biomass Gasification ◽  
High Humidity ◽  
Agricultural Ecosystems ◽  
Productive Potential ◽  
Co2 Balance ◽  
Environmentally Sound ◽  
The Impact ◽  
Organic Resources

In the present paper are presented the experimental results of biomass gasification, the biochair was produced from vineyards by controlled pyrolysis at 750 �C, in order to increase the fertility of soils, it was found the increase of the fertility produced by the development of the vegetables in the soil to which was added biochar. Soil was added to soil 4 g/dm3 biochar, 8 g/dm3 biochar, the soil had no high humidity, was taken at a time when it had not rained for at least one week, the soil pH was 8, in the soil with 8 g/dm3 biochar the plants increased compared to the soil with 4 g/dm3 and the soil without biochar. The biochar resulting from pyrolysis and gasification processes is a valuable amendment to agricultural soils and an efficient and economical way to seize carbon. Using biochar it is possible to increase the diversity of agricultural land in an environmentally sound way in areas with depleted soils, limited organic resources and insufficient water for development. Helps to soil carbon sequestration with negative CO2 balance, increases the productive potential of agricultural ecosystems.

The impact of preozonation and biodegradation on disinfection by-product formation

1992 ◽  
Vol 26 (9) ◽  
pp. 1217-1227 ◽  
Author(s):  
H SHUKAIRY ◽  
R SCOTTSUMMERS
Keyword(s):  
Product Formation ◽  
The Impact
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