page_title: Cigarette
section_title: Biodegradation
hierarchical_section_title: Cigarette / Environmental impact / Biodegradation
caption_attribution_description: English: Chemical hydrolysis of cellulose acetate
context_page_description: A cigarette is a narrow cylinder containing psychoactive material, typically tobacco, that is rolled into thin paper for smoking. Most cigarettes contain a "reconstituted tobacco" product known as "sheet", which consists of "recycled [tobacco] stems, stalks, scraps, collected dust, and floor sweepings", to which are added glue, chemicals and fillers; the product is then sprayed with nicotine that was extracted from the tobacco scraps, and shaped into curls. The cigarette is ignited at one end, causing it to smolder; the resulting smoke is orally inhaled via the opposite end. Most modern cigarettes are filtered, although this does not make them safer. Cigarette manufacturers have described cigarettes as a drug administration system for the delivery of nicotine in acceptable and attractive form. Cigarettes are addictive and cause cancer, chronic obstructive pulmonary disease, heart disease, and other health problems.
  The term cigarette, as commonly used, refers to a tobacco cigarette but is sometimes used to refer to other substances, such as a cannabis cigarette.
context_section_description: The first step in the biodegradation of cellulose acetate is the deactylation of the acetate from the polymer chain (which is the opposite of acetylation).  An acetate is a negative ion with the chemical formula of C₂H₃O₂⁻.  Deacetylation can be performed by either chemical hydrolysis or acetylesterase.  Chemical hydrolysis is the cleavage of a chemical bond by addition of water.  In the reaction, water (H₂O) reacts with the acetic ester functional group attached the cellulose polymer chain and forms an alcohol and acetate.  The alcohol is simply the cellulose polymer chain with the acetate replaced with an alcohol group. The second reaction is exactly the same as chemical hydrolysis with the exception of the use of an acetylesterase enzyme.  The enzyme, found in most plants, catalyzes the chemical reaction shown below.
  acetic ester + H₂O  ⇌ alcohol + acetate
  
  In the case of the enzymatic reaction, the two substrates (reactants) are again acetic ester and H₂O, the two products of the reaction are alcohol and acetate.  This reaction is exactly the same as the chemical hydrolysis.  Both of these products are perfectly fine in the environment. Once the acetate group is removed from the cellulose chain, the polymer can be readily degraded by cellulase, which is another enzyme found in fungi, bacteria, and protozoans. Cellulases break down the cellulose molecule into monosaccharides ("simple sugars") such as beta-glucose, or shorter polysaccharides and oligosaccharides. 
  These simple sugars are not harmful to the environment and are in fact are a useful product for many plants and animals.  The breakdown of cellulose is of interest in the field of biofuel. Due to the conditions that affect the process, large variation in the degradation time of cellulose acetate occurs.
caption: Chemical hydrolysis of cellulose acetate
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