Biodegradation formaldehyde

Different pathways have been proposed to explain the anaerobic biodegradation of formaldehyde according to the intermediate products observed.5-7... 

The biodegradation of the metabolites starts after exhaustion of formaldehyde in the medium. 

Zagomaya and colleagues22 reported the complete biodegradation of 2300 mg/L of formaldehyde in wastewater treated in an activated sludge plant, whereas Gerike and Gode26 observed that 30mg/L... 

Omil, F., Mendez, D., Vidal, G., Mendez, R., and Lema, J.M., Biodegradation of formaldehyde under anaerobic conditions, Enzyme Microb. Technol., 24, 255-262, 1999. 

Eiroa, M., Kennes, C., and Veiga, M.C., Simultaneous nitrification and formaldehyde biodegradation in an activated sludge unit, Biores. Technol., 96, 1914-1918, 2005. 

This case study illustrates the importance of dissolution/precipitation reactions in determining waste- reservoir compatibility. Adsorption was observed to immobilize most of the organic constituents in the waste except for formaldehyde. As with the Monsanto case study, biodegradation was an important process when wastes were diluted by formation waters, but the process became inhibited when undiluted waste reached a given location in the injection zone. 

In order to avoid further biodegradation of surfactants after sampling or during storage, various substances have been used for the preservation of samples. So far, mainly formaldehyde and salts of copper(II) and mercury(II) [7,14] have been applied, and formaldehyde has been found to be the most effective of these, although still not sufficient for long term storage. This topic is discussed in more detail in Chapter 4.3. 

Fig. 5.3.1. (a) 3-Phenyl-Cn-LAS and 2-phenyl-Ci2-LAS biodegradation in seawater (from Ref. [21]). The assays were performed by duplicate (circles) and an abiotic control (4% formaldehyde) (triangles), (b) Main intermediates generated from 3-phenyl-(4>)-Cn-LAS and 2-phenyl-(4>)-Ci2-LAS (upper graphs) and mixtures of several isomers (lower graphs) in seawater with an initial... 

Other nonfood applications of D-sorbitol result from etherification and polycondensation reactions providing biodegradable polyetherpolyols used for soft pol5mrethane foams and melamine/formaldehyde or phenol resins. Sizable amounts of D-sorbitol also enter into the production of the sorbitan ester surfactants (cf. later in this chapter). 

Biological. Complete microbial degradation to carbon dioxide was reported under anaerobic conditions by mixed or pure cultures. Under enzymatic conditions formaldehyde was the only product reported (Vogel et al., 1987). In a static-culture-flask screening test, methylene chloride (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. After 7 d, 100% biodegradation with rapid adaptation was observed (Tabak et al., 1981). 

Printing pastes should be recycled whenever possible. Disposal is possible by incineration and biological degradation. Problems can arise in biodegradation from preservatives added to the pastes to avoid microbial growth and in cases of high formaldehyde and heavy metal content. 

The compound formaldehyde is biodegrading in several systems simultaneously (1) a lake, modeled as a complete mix reactor (2) an estuary, modeled as three complete mixed reactors in series (3) a large river, modeled as 10 complete mixed reactors in series, and a small stream, modeled as a plug flow reactor. What is the nondimensional reaction/residence time, k p, that is required for each of these systems to reach a degradation of 50%, 90%, 99%, and 99.9% ... 

Toxic degradation products this effect is applicable to biodegradable polymers for example, degradation of poly(alkylcyanoacrylate) leads to the formation of formaldehyde which is considered toxic in humans. In the case of a bioerodible polyvinylpyrrolidone), the accumulation of the dissolved polymer in the liver raises a longterm toxicity issue. 

In ambient air, the primary removal mechanism for acrolein is predicted to be reaction with photochemically generated hydroxyl radicals (half-life 15-20 hours). Products of this reaction include carbon monoxide, formaldehyde, and glycolaldehyde. In the presence of nitrogen oxides, peroxynitrate and nitric acid are also formed. Small amounts of acrolein may also be removed from the atmosphere in precipitation. Insufficient data are available to predict the fate of acrolein in indoor air. In water, small amounts of acrolein may be removed by volatilization (half-life 23 hours from a model river 1 m deep), aerobic biodegradation, or reversible hydration to 0-hydroxypropionaldehyde, which subsequently biodegrades. Half-lives less than 1-3 days for small amounts of acrolein in surface water have been observed. When highly concentrated amounts of acrolein are released or spilled into water, this compound may polymerize by oxidation or hydration processes. In soil, acrolein is expected to be subject to the same removal processes as in water. 

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