scholarly journals Evaluation of Heterologous Biosynthetic Pathways for Methanol-Based 5-Aminovalerate Production by Thermophilic Bacillus methanolicus

2021 ◽  
Vol 9 ◽  
Author(s):  
Luciana Fernandes Brito ◽  
Marta Irla ◽  
Ingemar Nærdal ◽  
Simone Balzer Le ◽  
Baudoin Delépine ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Source ◽  
Raw Material ◽  
Methylotrophic Bacteria ◽  
Biosynthetic Pathways ◽  
Proof Of Concept ◽  
Thermophilic Bacillus ◽  
Bacillus Methanolicus ◽  
Biotechnological Processes ◽  
Putrescine Oxidase

The use of methanol as carbon source for biotechnological processes has recently attracted great interest due to its relatively low price, high abundance, high purity, and the fact that it is a non-food raw material. In this study, methanol-based production of 5-aminovalerate (5AVA) was established using recombinant Bacillus methanolicus strains. 5AVA is a building block of polyamides and a candidate to become the C5 platform chemical for the production of, among others, δ-valerolactam, 5-hydroxy-valerate, glutarate, and 1,5-pentanediol. In this study, we test five different 5AVA biosynthesis pathways, whereof two directly convert L-lysine to 5AVA and three use cadaverine as an intermediate. The conversion of L-lysine to 5AVA employs lysine 2-monooxygenase (DavB) and 5-aminovaleramidase (DavA), encoded by the well-known Pseudomonas putida cluster davBA, among others, or lysine α-oxidase (RaiP) in the presence of hydrogen peroxide. Cadaverine is converted either to γ-glutamine-cadaverine by glutamine synthetase (SpuI) or to 5-aminopentanal through activity of putrescine oxidase (Puo) or putrescine transaminase (PatA). Our efforts resulted in proof-of-concept 5AVA production from methanol at 50°C, enabled by two pathways out of the five tested with the highest titer of 0.02 g l–1. To our knowledge, this is the first report of 5AVA production from methanol in methylotrophic bacteria, and the recombinant strains and knowledge generated should represent a valuable basis for further improved 5AVA production from methanol.

scholarly journals Micro-recycling of spent Ni-Cd batteries for the obtention of electrocatalytic coatings

2022 ◽  
Author(s):  
Pedro Delvasto ◽  
Héctor Rueda ◽  
Andrés Monsalve ◽  
Ronald Vargas ◽  
Sergio Blanco ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Cyclic Voltammetry ◽  
Raw Material ◽  
Operating Voltage ◽  
Proof Of Concept ◽  
Dissolved Metals ◽  
Voltage Range ◽  
Catalytic Materials ◽  
Tafel Slopes ◽  
Wide Operating

Abstract A micro-recycling approach was explored to produce catalytic metallic coatings for the hydrogen evolution reaction (HER). For this aim, discarded Ni-Cd batteries were employed as raw material. After dismantling the batteries, the active powder material, containing Cd and Ni compounds, was leached in a solution containing citric acid and hydrogen peroxide. The dissolved metals were electro-deposited on copper plates using a two electrodes cell at the following potentials (mV): -1900, -2000, and -2100 mV. The CdNi coating produced at -2000 mV, contained 92.6 % Cd and 7.4 % Ni. This coating was studied by cyclic voltammetry (CV) and potentiodynamic analysis in two different KOH solutions (0.1 M and 1.0 M). The CV analysis showed that the CdNi electrode was electrochemically stable in a wide operating voltage range (between oxygen evolution reaction and HER). Using an uncompensated resistance correction, the Tafel slopes for HER were obtained. The potentiodynamic analysis revealed that the synthesized CdNi electrode showed a catalytic activity for HER just 25.5 % smaller than the correspondent response of a standard pure Ni electrode. Our results serve as a proof of concept about the application of micro-recycling of spent batteries to produce sustainable electroactive catalytic materials for hydrogen production.

Improving the efficiency of enzymatic hydrolysis of Eucalyptus residues with a modified aqueous ammonia soaking method

2018 ◽  
Vol 33 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Dan Huo ◽  
Qiulin Yang ◽  
Guigan Fang ◽  
Qiujuan Liu ◽  
Chuanling Si ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Enzymatic Hydrolysis ◽  
Aqueous Ammonia ◽  
Pulp Mill ◽  
Fiber Surface ◽  
Raw Material ◽  
Sem Images ◽  
Aqueous Ammonia Soaking ◽  
Guaiacyl Lignin ◽  
Hydrolysis Of

Abstract Eucalyptus residues from pulp mill were pretreated with aqueous ammonia soaking (AAS) method to improve the efficiency of enzymatic hydrolysis. The optimized condition of AAS was obtained by response surface methodology. Meanwhile, hydrogen peroxide was introduced into the AAS system to modify the AAS pretreatment (AASP). The results showed that a fermentable sugar yield of 64.96 % was obtained when the eucalypt fibers were pretreated at the optimal conditions, with 80 % of ammonia (w/w) for 11 h and keeping the temperature at 90 °C. In further research it was found that the addition of H2O2 to the AAS could improve the pretreatment efficiency. The delignification rate and enzymatic digestibility were increased to 64.49 % and 73.85 %, respectively, with 5 % of hydrogen peroxide being used. FTIR analysis indicated that most syringyl and guaiacyl lignin and a trace amount of xylan were degraded and dissolved during the AAS and AASP pretreatments. The CrI of the raw material was increased after AAS and AASP pretreatments, which was attributed to the removal of amorphous portion. SEM images showed that microfibers were separated and explored from the initial fiber structure after AAS pretreatment, and the AASP method could improve the destructiveness of the fiber surface.

Meteorite as raw material for Direct Metal Printing: A proof of concept study

2018 ◽  
Vol 143 ◽  
pp. 76-81 ◽  
Author(s):  
Karel Lietaert ◽  
Lore Thijs ◽  
Bram Neirinck ◽  
Thomas Lapauw ◽  
Brian Morrison ◽  
...  
Keyword(s):  
Raw Material ◽  
Proof Of Concept ◽  
Concept Study ◽  
Metal Printing

Anaerobic Treatment of Bleached TMP and CTMP Effluent in the Biopaq UASB System

1991 ◽  
Vol 24 (3-4) ◽  
pp. 331-345 ◽  
Author(s):  
L. H. A. Habets ◽  
A. L. de Vegt
Keyword(s):  
Hydrogen Peroxide ◽  
Anaerobic Treatment ◽  
Full Scale ◽  
Resin Acids ◽  
Raw Material ◽  
Complexing Agent ◽  
Methanogenic Activity ◽  
Treated Effluent ◽  
Pilot Work ◽  
Cost Efficient

The effluents from CTMP mills are on the one hand too dilute for evaporation and recovery, and on the other hand too highly polluted for conventional aerobic secondary treatment. In summer 1986 we therefore started an extensive research program in cooperation with the Ahlström Engineering division in Savonlinna, Finland, and Paques-Lavalin in Toronto, Canada, in order to investigate the anaerobic treatability of CTMP effluent, using UASB technology. This research included fundamental work in the lab, as well as on-site pilot work in Finland and in Canada. As a result, two full-scale plants are in operation. The first plant was started up in October 1988 at Quesnel River Pulp in B.C., Canada, and is treating up to 140 tons of COD per day in two reactors of 3500 m3 each. The second plant was ready for start-up in January 1990 at the Enso-Gutzeit Kotka mill in Finland. The cautious approach for these types of effluents was necessary due to earlier reports on the toxicity of softwood extractives, bleaching agent hydrogen peroxide, complexing agent DTPA and high sulphur levels. Besides this, it was necessary to confirm that granular seed sludge would not deteriorate but would develop normally. The behaviour of hydrogen peroxide was especially interesting and the high redox potential caused could be resolved in a very cost-efficient way without utilising chemicals, enzymes or activated sludge. Resin acids were indentified to be responsible for reducing methanogenic activity considerably. They were eliminated during aerobic post-treatment to very low levels. Lab studies clearly demonstrated how methanogenic activity could be increased by adding dilution water or aerobically treated effluent. The concentration of the resin acids appeared to be associated with raw material (spruce, fir or pine), the season (summer or winter) and with fine fibrous material in the effluent. Sulphur levels in the effluent were relatively high, but resulting sulphide levels were not toxic to methanogens and COD/sulphur ratios were high enough to achieve acceptable removal efficiencies. The paper presents the results from research as well as flow diagrams of the full-scale plants, and results from more than one year full-scale operation at Quesnel River Pulp in B.C. Canada.

scholarly journals Induction of the Galactose Enzymes in Escherichia coli Is Independent of the C-1-Hydroxyl Optical Configuration of the Inducer d-Galactose

2008 ◽  
Vol 190 (24) ◽  
pp. 7932-7938 ◽  
Author(s):  
Sang Jun Lee ◽  
Dale E. A. Lewis ◽  
Sankar Adhya
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Carbon Source ◽  
The Other ◽  
Biosynthetic Pathways ◽  
In Vitro Experiments ◽  
Metabolizing Enzymes ◽  
Optical Configuration

ABSTRACT The two optical forms of aldohexose galactose differing at the C-1 position, α-d-galactose and β-d-galactose, are widespread in nature. The two anomers also occur in di- and polysaccharides, as well as in glycoconjugates. The anomeric form of d-galactose, when present in complex carbohydrates, e.g., cell wall, glycoproteins, and glycolipids, is specific. Their interconversion occurs as monomers and is effected by the enzyme mutarotase (aldose-1-epimerase). Mutarotase and other d-galactose-metabolizing enzymes are coded by genes that constitute an operon in Escherichia coli. The operon is repressed by the repressor GalR and induced by d-galactose. Since, depending on the carbon source during growth, the cell can make only one of the two anomers of d-galactose, the cell must also convert one anomer to the other for use in specific biosynthetic pathways. Thus, it is imperative that induction of the gal operon, specifically the mutarotase, be achievable by either anomer of d-galactose. Here we report in vivo and in vitro experiments showing that both α-d-galactose and β-d-galactose are capable of inducing transcription of the gal operon with equal efficiency and kinetics. Whereas all substitutions at the C-1 position in the α configuration inactivate the induction capacity of the sugar, the effect of substitutions in the β configuration varies depending upon the nature of the substitution; methyl and phenyl derivatives induce weakly, but the glucosyl derivative does not.

scholarly journals DELIGNIFICATION OF VEGETABLE RAW MATERIAL CATALYTIC BY HYDROGEN PEROXIDE AND PEROXI-COMBINATIONS (REVIEW)

2020 ◽  
pp. 331-349
Author(s):  
Robert Zus'evich Pen ◽  
Natal'ya Viktorovna Karetnikova ◽  
Ida L'vovna Shapiro
Keyword(s):  
Hydrogen Peroxide ◽  
Sodium Molybdate ◽  
Raw Material ◽  
State University ◽  
Heating Value ◽  
Accurate Definition ◽  
Stage Process ◽  
Coniferous Wood ◽  
The One ◽  
Definition Of

Given review is a publication of the studies result in the field of vegetable raw material delignification by the hydrogen peroxide and by the peroxicombinations, carried out in Siberian State University after publishing of the previous review by the authors on same themes in 2005 year. Basically these studies are directed on decision of the following problems: more accurate definition of the technological characters of the process coniferous wood delignification with catalytic complex, including titanium dioxide, sodium tungstate and sodium molybdate, sulfuric acid; intensification of wood soaking by the peroxide cooking solution with using of vacuum and ultrasound; the receipt and estimation of the peroxide cellulose properties from of wheat straw stems, study of the straw cellulose particularities bleaching, elaboration of the one-stage process to receipt of the microcrystalline cellulose; concentration of organic substances of the peroxide waste solution by the ultrafiltration, estimation its heating value.

scholarly journals Production of lactic acid by Enterococcus faecalis on waste glycerol from biodiesel production

2020 ◽  
Vol 26 (2) ◽  
pp. 151-156
Author(s):  
Jovan Ciric ◽  
Natasa Jokovic ◽  
Slavica Ilic ◽  
Sandra Konstantinovic ◽  
Dragisa Savic ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Carbon Source ◽  
Enterococcus Faecalis ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Raw Material ◽  
Biodiesel Production ◽  
Waste Glycerol ◽  
Pure Glycerol ◽  
Microbial Utilization

Waste glycerol from biodiesel production is a valuable raw material that has been used to produce valuable microbial metabolites. In this work, the possibility of microbial utilization of waste glycerol obtained as a by-product in biodiesel production from sunflower and rapeseed oil by the lactic acid bacterium Enterococcus faecalis MK3-10A on a laboratory level was studied. For comparison, pure glycerol and glucose were used as carbon sources. The kinetics of the microbial biomass growth, the carbon source utilization, and the lactic acid production were monitored. The bacterium E. faecalis MK3-10A better grew in the media with glucose or pure glycerol as a carbon source, but the lactic acid production rate was the highest (14.6 mg/(ml/day)) in the medium with waste glycerol from the sunflower oil-based biodiesel production. Therefore, this waste glycerol might be a promising carbon source for lactic acidbacteria cultivation and lactic acid production.

scholarly journals Kinetic compartmentalization by unnatural reaction for itaconate production

2021 ◽  
Author(s):  
Daeyeol Ye ◽  
Myung Hyun Noh ◽  
Jo Hyun Moon ◽  
Alfonsina Milito ◽  
Minsun Kim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metabolic Engineering ◽  
Carbon Source ◽  
Metabolic Pathways ◽  
Mitochondrial Membrane ◽  
Membrane System ◽  
Proof Of Concept ◽  
Substrate Availability ◽  
Competitive Reactions ◽  
Metabolic Reactions

Abstract Physical compartmentalization of metabolisms using membranous organelles in eukaryotes is helpful for chemical biosynthesis to ensure the availability of substrates from competitive metabolic reactions. Bacterial hosts lack such a membranous system, which is one of the major limitations for efficient metabolic engineering. Here, we introduced kinetic compartmentalization as an alternative strategy to enable substrate availability from competitive reactions. This method utilizes a non-natural biochemical reaction performed by an engineered enzyme to kinetically isolate the metabolic pathways and ensure substrate availability for the desired reaction. As a proof of concept, we could successfully demonstrate kinetic separation for efficient itaconate production from acetate in Escherichia coli, mimicking the native mitochondrial membrane system in Aspergillus species. Despite the utilization of the non-preferred carbon source, kinetic compartmentalization could lead to substantial increases of itaconate in both yield and titer, suggesting enough potential of our strategy for broad applications in diverse engineering.

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