Aerobic biodegradation of cellulose acetate

Abstract

SYNOPSISTwo separate assay systems were used to evaluate the biodegradation potential of cellulose acetate: an in uitro enrichment cultivation technique (closed batch system), and a system in which cellulose diacetate (CDA) films were suspended in a wastewater treatment system (open continuous feed system). The in uitro assay employed a stable enrichment culture, which was initiated by inoculating a basal salts medium containing cellulose acetate with 5% ( v/v ) activated sludge. Microscopic examination revealed extensive degradation of CDA (DS = 2.5) fibers after 2-3 weeks of incubation. Characterization of the CA fibers recovered from inoculated flasks demonstrated a lower average degree of substitution and a change in the mol wt profiles. I n uitro enrichments with CDA (DS = 1.7) films were able to degrade > 80% of the films in 4-5 days. Cellulose acetate (DS = 2.5) films required 10-12 days for extensive degradation. Films prepared from cellulose triacetate remained essentially unchanged after 28 days in the in uitro assay. The wastewater treatment assay was less active than the in uitro enrichment system. For example, approximately 27 days were required for 70% degradation of CDA (DS = 1.7) films to occur while CDA (DS = 2.5) films required approximately 10 weeks before significant degradation was obtained. Supporting evidence for the biodegradation potential of cellulose acetate was obtained through the conversion of cellulose [l-14C]-acetate to 14C02 in the in uitro assay. The results of this work demonstrate that cellulose acetate fibers and films are potentially biodegradable and that the rate of biodegradation is highly dependent on the degree of substitution.

Degradation of Cellulose Acetate-Based Materials: A Review

“…1). Buchanan, Gardner, and Komarek in 1993 [4] studied two aerobic assay systems for degrading CA films: an in vitro enrichment cultivation technique and an activated sludge wastewater treatment system. The enrichment culture was able to degrade CA films within 2-3 weeks, as indicated by 67% weight loss.…”

“…Later the importance of the deacetylation step was shown, when it was learned that acetyl esterase enzymes are common in microorganisms. Currently CA is generally recognized as a biodegradable polymer within the scientific community [4][5][6][7][8]. Recent work has allowed a considerable increase in the knowledge of the enzymology of non-substituted and acetylated polysaccharides, thus illuminating the biodegradation mechanism.…”

Microbial Degradation of Woven Fabrics and Protection Against Biodegradation

“…Its rate of microbiological decomposition is comparable to that of cotton. Cellulose acetate is produced by the acetylation of cellulose with acetic anhydride, as a result of which the product has a maximal degree of acetylation, and the fibre becomes more resistant to microbiological decomposition than cellulose (Buchanan et al, 1993, Buschle-Diller et al, 1994Salerno-Kochan & Szostak-Kotowa, 2001;Szostak-Kot, 2005).…”

The Age of Plastic: Ingenuity and Responsibility, Proceeding of the 2012 MCI Symposium

“…In the short term, cellulose acetate (CA) is vulnerable to damage by ultraviolet light and biodeterioration, and one can expect CA to break down quite quickly in the environment relative to many other synthetic polymers (Buchanan et al, 1993;Puls et al, 2010). For CA that is not discarded outdoors but rather is protected in an indoor environment, acetate side groups grafted onto the cellulose during production of the polymer slowly are released as acetic acid, which drops the pH of the material, cleaves the cellulose polymer chain, and gives off the notorious "vinegar" odor of the deteriorating material.…”