Analytical methods used to assess biodegradation of fibers and films

5 Analytical methods used to assess biodegradation of fibers and films 

On the other hand, if the substrate is large and insoluble in water, such as a fiber or a film of biodegradable material, physical measurements are commonly used to assess the initial microbial attack on the substrate. These methods include microscopic examination, measure of weight loss, or measure of the loss of mechanical strength. As the biodegradation of the fiber continues, individual small molecules are released and chemical analyses of monomers and products of mineralization can be detected. Often, several of these methods are used in a single study to confirm and characterize the biodegradation of the test material. 

1 Detecting subtle changes in fiber structure or composition 

Some of the initial reactions during the biodegradation of a fiber may produce only small changes in its stmcture or composition. These are typically observed using very sophisticated instrumental methods. Amass et al. [57] reviewed the use of many of these methods, so only a few examples are given here. 

The depolymerization of fibers or films leads to the formation of water-soluble small molecules this results in the dissolution of the fiber or film, accounting for the holes in the film in Fig. 1.1. This type of biodegradation can also be observed by placing a polymer on the surface of an aqueous medium or in an agar plate. As an example, Ratajska et al. [46] floated chitosan (A-deacetylated chitin comprised of chains of o-glucosamine) in liquid medium containing mixed microbial community from a wastewater. Initially, the polymer covered essentially the entire surface of the liquid. Over a 5-week incubation period, dissolution caused the diameter of the polymer mat to decrease until it was about one-fifth of its original size. 

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