Biodegradable, definition

The advantage of this test is that it is quick and easy to do, and gives an indication of biodegradation potential. However, the test is not definitive, because any impurities in the plastic, such as plasticizers and solvents, may interfere with the test by promoting growth, and thus give false positive results. 

Indications for the formation of analogous species in microbial metabolism of LAS were found by Knepper and Kruse [33] during biotransformation of commercial LAS surfactant on an FBBR. However, the low concentrations of the tentative metabolites in the test liquor, which eluted under the applied reversed-phase (RP)-HPLC conditions somewhat earlier than the normal SPC, did not permit acquisition of full-scan mass spectra as was needed for unequivocal identification. Further evidence for the formation of the intermediate with a double bond in the alkanoate moiety was reported by Bird [103]. During biodegradation of Cn-LAS by a bacterial strain, a new UV adsorption band centred near 260 nm was detected, which was assumed to result from a double bond, although a definite confirmation could not be provided. 

Note 2 Usually, degradation results in the loss of, or deterioration in useful properties of the material. However, in the case of biodegradation (degradation by biological activity), polymers may change into environmentally acceptable substances with desirable properties (see Definition 3.1... 

To use organic molecules as a food source, microorganisms have to be able to take up the substance and metabolize it within their cells. A prerequisite is that the molecules are water-soluble and that they are small enough to pass through the cell walls and membranes of the microorganism. Polymers are typically not water-soluble and, by definition, are not small molecules [4]. Therefore, the biodegradation of polymers typically needs to follow four distinct steps. 

In contrast to many other polymers classified as biodegradable, PVA exhibits a backbone solely made up of carbon. The presence of a heteroatom like O or N in the main chain is definitely not a prerequisite for Nature to handle a polymeric structure that does not exist in nature. PVA degradation starts with random oxidations of the polymer backbone in the extracellular or periplasmic space of some microbes. Specific enzymes able to detect such sites of first attack continue in a hydrolytic way, yielding ever smaller polymer fragments that finally can be metabolised by the microbe or the microbial community. 

According to the definition by Japan BioPlastic Association (JBPA), there are two types of so-called GreenPla. One is biodegradable plastic, which means that the plastic will be completely decomposed into H2O and CO2 by environmental... 

Lactic acid is an example. It is conveniently added to the polyol and upon reaction with the isocyanate, it is inserted into the backbone. Upon exposure to fluids in the body, the polymer is cut at the insertion site. The reduction in tensile properties is dramatic. Although the fragments are suspect, the result is by definition degradable. A number of researchers at W.R. Grace prepared biodegradable hydrophilic polyurethanes by a similar technique but the product was never available commercially. 

---