Simultaneous synthesis of lactic acid and hydrogen from sugars via capnophilic lactic fermentation by Thermotoga neapolitana cf capnolactica

Pradhan, Nirakar; d’Ippolito, Giuliana; Dipasquale, Laura; Esposito, Giovanni; Pánico, Antonio; Lens, Piet N.L.; Fontana, Angelo

doi:10.1016/j.biombioe.2019.04.007

Cited by 22 publications

(31 citation statements)

References 26 publications

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“…Thus, pH is a critical factor to control sugar consumption and direct end-products formation [ 65 , 67 , 117 , 119 , 122 ]. Gradual pH drop causes enzyme activity loss [ 123 ].…”

Section: Operating Conditionsmentioning

confidence: 99%

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Effect of Cultivation Parameters on Fermentation and Hydrogen Production in the Phylum Thermotogae

Lanzilli

Esercizio

Vastano

et al. 2020

IJMS

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The phylum Thermotogae is composed of a single class (Thermotogae), 4 orders (Thermotogales, Kosmotogales, Petrotogales, Mesoaciditogales), 5 families (Thermatogaceae, Fervidobacteriaceae, Kosmotogaceae, Petrotogaceae, Mesoaciditogaceae), and 13 genera. They have been isolated from extremely hot environments whose characteristics are reflected in the metabolic and phenotypic properties of the Thermotogae species. The metabolic versatility of Thermotogae members leads to a pool of high value-added products with application potentials in many industry fields. The low risk of contamination associated with their extreme culture conditions has made most species of the phylum attractive candidates in biotechnological processes. Almost all members of the phylum, especially those in the order Thermotogales, can produce bio-hydrogen from a variety of simple and complex sugars with yields close to the theoretical Thauer limit of 4 mol H2/mol consumed glucose. Acetate, lactate, and L-alanine are the major organic end products. Thermotagae fermentation processes are influenced by various factors, such as hydrogen partial pressure, agitation, gas sparging, culture/headspace ratio, inoculum, pH, temperature, nitrogen sources, sulfur sources, inorganic compounds, metal ions, etc. Optimization of these parameters will help to fully unleash the biotechnological potentials of Thermotogae and promote their applications in industry. This article gives an overview of how these operational parameters could impact Thermotogae fermentation in terms of sugar consumption, hydrogen yields, and organic acids production.

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“…Thus, pH is a critical factor to control sugar consumption and direct end-products formation [ 65 , 67 , 117 , 119 , 122 ]. Gradual pH drop causes enzyme activity loss [ 123 ].…”

Section: Operating Conditionsmentioning

confidence: 99%

“…In recent years, many researchers have been focusing on the optimization of fermentation performance towards the production of hydrogen and other target end-products [ 30 , 43 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Cultivation Parameters on Fermentation and Hydrogen Production in the Phylum Thermotogae

Lanzilli

Esercizio

Vastano

et al. 2020

IJMS

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“…In the last years, we reported that T. neapolitana also operates a novel, anaplerotic process named capnophilic lactic fermentation (CLF) for the synthesis of almost enantiopure L-lactic acid (LA) without affecting H 2 production d'Ippolito et al, 2014;Pradhan et al, 2016bPradhan et al, , 2019Nuzzo et al, 2019). The metabolic process is activated by CO 2 (capnophilic means "requiring CO 2 ") and, nominally, is dependent on a Janus pathway including a catabolic branch leading to acetyl-CoA (AcCoA) from sugars by glycolysis, and an anabolic branch that combines AcCoA and CO 2 to give LA through reduction of newly synthesized pyruvate (PYR) by a NADH-dependent lactic dehydrogenase (LDH) (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

CO2-Induced Transcriptional Reorganization: Molecular Basis of Capnophillic Lactic Fermentation in Thermotoga neapolitana

et al. 2020

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Capnophilic lactic fermentation (CLF) is a novel anaplerotic pathway able to convert sugars to lactic acid (LA) and hydrogen using CO 2 as carbon enhancer in the hyperthermophilic bacterium Thermotoga neapolitana. In order to give further insights into CLF metabolic networks, we investigated the transcriptional modification induced by CO 2 using a RNA-seq approach. Transcriptomic analysis revealed 1601 differentially expressed genes (DEGs) in an enriched CO 2 atmosphere over a total of 1938 genes of the T. neapolitana genome. Transcription of PFOR and LDH genes belonging to the CLF pathway was up-regulated by CO 2 together with 6-phosphogluconolactonase (6PGL) and 6-phosphogluconate dehydratase (EDD) of the Entner-Doudoroff (ED) pathway. The transcriptomic study also revealed up-regulation of genes coding for the flavin-based enzymes NADH-dependent reduced ferredoxin:NADP oxidoreductase (NFN) and NADferredoxin oxidoreductase (RNF) that control supply of reduced ferredoxin and NADH and allow energy conservation-based sodium translocation through the cell membrane. These results support the hypothesis that CO 2 induces rearrangement of the central carbon metabolism together with activation of mechanisms that increase availability of the reducing equivalents that are necessary to sustain CLF. In this view, this study reports a first rationale of the molecular basis of CLF in T. neapolitana and provides a list of target genes for the biotechnological implementation of this process.

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“…The demand for Lactic Acid (LA) is increasing day by day at a very fast rate in several industrial areas. LA is a sugar-based chemical and is applicable both to food and various non-food industries, such as cosmetic (as a moisturizer) and pharmaceutical (for making parental solutions) industries, so as to produce chemicals (oxygenated) as plant growth regulators and special chemical intermediates [1][2][3][4]. In addition, it (as Poly-Lactic Acid (PLA)) has gained much attention in the polymer sector as a monomer for producing biodegradable and environment-friendly plastics [5].…”

Section: Introductionmentioning

confidence: 99%

Reactive Extraction of Lactic Acid using Environmentally Benign Green Solvents and Synergistic Mixture of Extractants

Kumar

Thakur

2019

Scientia Iranica

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An environment-friendly reactive extraction method as a novel phase separation technique is considered to extract Lactic Acid (LA) from the aqueous solution by means of environmentally benign green diluents along with a synergistic mixture of extractants. Reactive extraction of LA was carried out through a synergistic mixture of extractants (trioctylamine (TOA), Aliquat336, and tridodecylamine (TDDA)), organic solvents, and non-toxic and biocompatible green diluents. According to the various investigated LA reactive extraction processes, the process featuring sun ower oil, synergist extractant (TOA and Aliquat336), and Butan-2-ol was found to be the most favorable system. The LA distribution coe cient (K D = 27:75 0:22) and extraction e ciency ( = 97:17 0:54%) were obtained by a system consisting of LA concentration (0.05 [M]), TOA (15%, v/v), Aliquat336 (15%, v/v), phase ratio (1:1, v/v), solvent ratio (2.5, v/v), agitation speed (100 rpm), and stirring time (120 min). The main driving force for this research work on the LA reactive extraction from the aqueous solution is the development of a suitable combination of extractants, organic solvents, and natural solvents that possesses high a nity with LA and, also, has lower toxicity with respect to LA-producing microbes.

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Simultaneous synthesis of lactic acid and hydrogen from sugars via capnophilic lactic fermentation by Thermotoga neapolitana cf capnolactica

Cited by 22 publications

References 26 publications

Effect of Cultivation Parameters on Fermentation and Hydrogen Production in the Phylum Thermotogae

Effect of Cultivation Parameters on Fermentation and Hydrogen Production in the Phylum Thermotogae

CO2-Induced Transcriptional Reorganization: Molecular Basis of Capnophillic Lactic Fermentation in Thermotoga neapolitana

Reactive Extraction of Lactic Acid using Environmentally Benign Green Solvents and Synergistic Mixture of Extractants

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