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Industrial Prospects of Bacterial Microcompartment Technologies
Published in Deepak Kumar Verma, Ami R. Patel, Sudhanshu Billoria, Geetanjali Kaushik, Maninder Kaur, Microbial Biotechnology in Food Processing and Health, 2023
Shagun Rastogi, Chiranjit Chowdhury
Several enteric bacteria degrade rhamnose and fucose, the common plant sugars under an anaerobic environment, and produce 1,2-PD; which is then taken up as carbon and energy source by these bacteria (Obradors et al., 1988). During 1,2-PD degradation, the substrate gets converted to propionaldehyde by diol dehydratase, a coenzyme B12-dependent enzyme (Bobik et al., 1997; Chowdhury et al., 2014) (Figure 10.3). Propionaldehyde dehydrogenase converts propionaldehyde to propionyl-CoA. In aerobic respiration, propionyl-CoA feeds into TCA (tricarboxylic acid cycle) cycle via the methyl citrate pathway (Horswill and Escalante-Semerena, 1999; Chowdhury et al., 2014). Therefore, 1,2-PD serves as both carbon and energy source in aerobic conditions (Jeter, 1990). However, an earlier study reveals that Salmo- nella can respire 1,2-PD anaerobically in the presence of tetrathionate. In anaerobic conditions, tetrathionate serves as the terminal electron acceptor (Price-Carter et al., 2001). It has been shown that breakdown of 1,2-PD occurs inside MCP (Bobik et al., 1997; Chowdhury et al., 2014) (Figure 10.3). The function of the Pdu MCP is to isolate propionaldehyde to mitigate cytotoxicity and DNA damage caused by toxic aldehyde intermediate. It was shown that propionaldehyde is built up to a toxic level in the mutants that disrupt shell formation during growth on 1,2-PD (Havemann et al., 2002; Sampson and Bobik, 2008).
Technical Applicability
Published in Gerard F. Arkenbout, Melt Crystallization Technology, 2021
The crude product from the recovery section contains significant quantities of water, acrolein and acetic acid and some minor impurities such as formaldehyde, formic acid, acetaldehyde, propionaldehyde, propionic acid, maleic acid and heavy impurities (see, e.g., Kirk-Othmer, 1978). The purification system includes a solvent extraction followed by four distillation columns to effect the rejections of most of the impurities and recovery of solvent for reuse in extraction. The principal losses of acrylic acid in this operation are due to dimerization of acrylic acid to 3-acryloxypropionic acid. Mild conditions and short residence times are maintained and polymerization inhibitors are fed throughout the separations section to minimize polymer and dimer formation. The glacial acrylic acid produced in this stage of the process typically is at least 98–99% pure. Recovery of acrylic acid is about 95%.
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Products of combustion produced from burning plastics and other materials are the most significant hazard to both occupants of a building and firefighters during a fire. Plastic materials that contain only carbon and hydrogen in their formulation will generate only carbon, carbon monoxide, carbon dioxide and water as they burn. Intermediate products of combustion, however, are also produced and can include acrolein, formaldehyde, acetaldehyde, propionaldehyde and butraldehyde. Members of the aldehyde hydrocarbon family are irritants and flammable, with wide flammable ranges. Acrolein and carbon monoxide are lethal poisons. In addition to being toxic, carbon monoxide is also extremely flammable. Examples of carbon- and hydrogen-based plastics include polyethylene, polypropylene and polystyrene. Combustible products produced from burning plastics containing only carbon and hydrogen are the same as natural polymers such as wood, paper and other Class A combustible materials. Plastics containing carbon, hydrogen and oxygen produce the same combustion products as those containing just carbon and hydrogen.
Identification of effective control technologies for additive manufacturing
Published in Journal of Toxicology and Environmental Health, Part B, 2022
Johan du Plessis, Sonette du Preez, Aleksandr B. Stefaniak
Väisänen et al. (2022) measured particles, VOCs, and carbonyls emitted from an MJ printer. The printer had a built-in LEV duct, and samples were collected from the lab room air and from the printer exhaust ventilation duct (operating at 7 ACH) when using different resins. Most noteworthy was the distinction made between emissions from a VeroBlackPlus ink-like resin (henceforth, black) and other resins (a combination of clear, white, magenta, cyan, and yellow, henceforth, multi). Compared with room levels during printing, the LEV system was efficient in removing 62.1% (multi) to 68.6% (black) of particles measured using a CNC, 97.6% (multi) to 96.8% (black) of TVOC, and 44.2% (multi) to 57.9% (black) of carbonyls. Individual VOCs were removed with an efficacy of up to 98.9% (isobornyl alcohol, black). The removal of individual carbonyls ranged from 35.3% (formaldehyde, black) to 75.0% (acetone and propionaldehyde, black; 2-butanone, multi).
Volatile organic compound and particulate emissions from the production and use of thermoplastic biocomposite 3D printing filaments
Published in Journal of Occupational and Environmental Hygiene, 2022
Antti Väisänen, Lauri Alonen, Sampsa Ylönen, Marko Hyttinen
The concentrations of carbonyl compounds were notably affected by the higher extrusion temperature of the 3D printer in comparison to the lower processing temperature used during filament production. The measured carbonyl concentrations are presented in Table 3. 2-Butanone, acetaldehyde, acetone, and formaldehyde were the most abundantly encountered carbonyls which together contributed for 84–98% of the cumulative carbonyl concentrations which ranged between 60–91 µg/m3 during filament extrusion and 190–253 µg/m3 during 3D printing. Acetone was detected in the highest concentration, at 83 µg/m3 level during 3D printing of pure PLA. Peak concentrations for 2-butanone, acetaldehyde and formaldehyde were 73, 32, and 41 µg/m3, respectively, measured while printing different BC feedstocks. Several other carbonyls (acrolein, methacrolein and benzaldehyde) were detected at low (below 5 µg/m3) concentrations as well. The following carbonyls were detected at below 5 µg/m3 levels in the background: 2-butanone, acetaldehyde, acetone, acrolein, formaldehyde, hexaldehyde, and propionaldehyde. The used analysis method was selective and only the compounds in the reference material were able to be identified, and other carbonyls evaded the method. However, no distinct phantom peaks representing unidentified compounds were found in the chromatograms.
Ni@zeolite-Y nanoporous; a valuable and efficient nanocatalyst for the synthesis of N-benzimidazole-1,3-thiazolidinones
Published in Green Chemistry Letters and Reviews, 2018
Mehdi Kalhor, Soodabeh Banibairami, Seyed Ahmad Mirshokraie
By extension of this method and employing various aromatic aldehydes under the optimized conditions, some 2-((1H-benzo[d]imidazol-2-ylamino)(aryl) 1,3-thiazolidin-4-one derivatives were synthesized via one-pot reaction. The results presented in Table 3. Based on these results, the nanocatalyst showed high activity for the preparation of various types of aryl aldehydes to afford the corresponding 1,3-thiazolidin-4-ones in excellent yields in short reaction times. Additionally, the work-up procedure was very simple, the amount of used catalyst is low and the time of the reaction is short in comparison to some previous methods. It should be noted that the yield of the corresponding product did not improve using aliphatic aldehydes such as formaldehyde, acetaldehyde, and propionaldehyde. This may suggest that donor-acceptor interactions between the π-electrons of the aromatic ring and empty d-orbital of surface nickel ions can improve this process for aromatic aldehydes.