Editing Biodegradation (section)

== Mechanisms ==
The process of biodegradation can be divided into three stages: biodeterioration, biofragmentation, and [[assimilation (biology)|assimilation]].<ref name=":0" /> Biodeterioration is sometimes described as a surface-level degradation that modifies the mechanical, physical and chemical properties of the material. This stage occurs when the material is exposed to [[Abiotic component|abiotic]] factors in the outdoor environment and allows for further degradation by weakening the material's structure. Some abiotic factors that influence these initial changes are compression (mechanical), light, temperature and chemicals in the environment.<ref name=":0">{{cite journal|vauthors=Lucas N, Bienaime C, Belloy C, Queneudec M, Silvestre F, Nava-Saucedo JE|title=Polymer biodegradation: mechanisms and estimation techniques|journal=Chemosphere|volume=73|issue=4|pages=429–42|date=September 2008|pmid=18723204|doi=10.1016/j.chemosphere.2008.06.064|bibcode=2008Chmsp..73..429L}}</ref>&nbsp;While biodeterioration typically occurs as the first stage of biodegradation, it can in some cases be parallel to biofragmentation.<ref name=":1">{{cite book|last=Muller|first=Rolf-Joachim|editor-first=Alexander|editor-last=Steinbüchel|name-list-style=vanc|chapter=Biodegradability of Polymers: Regulations and Methods for Testing|title=Biopolymers|publisher=Wiley-VCH|isbn=978-3-527-30290-1|chapter-url=https://application.wiley-vch.de/books/biopoly/pdf_v10/vol10_19.pdf|doi=10.1002/3527600035.bpola012|year=2005|access-date=2018-09-19|archive-date=2018-09-19|archive-url=https://web.archive.org/web/20180919062117/https://application.wiley-vch.de/books/biopoly/pdf_v10/vol10_19.pdf|url-status=dead}}</ref> Hueck,<ref>{{Cite journal|last=Hueck|first=Hans|date=January 1966|title=The biodeterioration of materials as part of hylobiology|journal=Material und Organismen|volume=1|pages=5–34|via=ISSN 00255270}}</ref> however, defined Biodeterioration as the undesirable action of living organisms on Man's materials, involving such things as breakdown of stone facades of buildings,<ref name=":4">{{Cite book|title=Introduction to Biodeterioration|last=Allsopp|first=Dennis|publisher=Cambridge University Press|year=2004|isbn=9780511617065|location=Cambridge}}</ref> corrosion of metals by microorganisms or merely the esthetic changes induced on man-made structures by the growth of living organisms.<ref name=":4" />

Biofragmentation of a [[polymer]] is the [[lytic]] process in which bonds within a polymer are cleaved, generating [[oligomer]]s and [[monomer]]s in its place.<ref name=":0" /> The steps taken to fragment these materials also differ based on the presence of oxygen in the system. The breakdown of materials by microorganisms when oxygen is present is [[aerobic digestion]], and the breakdown of materials when oxygen is not present is [[anaerobic digestion]].<ref name=":2">{{Cite web|url=http://www.polimernet.com/Docs/Aerobic%20-%20Anaerobic%20Biodegredation%20en.pdf|archive-url=https://web.archive.org/web/20110419204604/http://polimernet.com/Docs/Aerobic%20-%20Anaerobic%20Biodegredation%20en.pdf|archive-date=2011-04-19|url-status=live|title=Aerobic and Anaerobic Biodegradation|work=Fundamentals of Aerobic & Anaerobic Biodegradation Process|publisher=Polimernet Plastik San. Tic. Ltd. Şti.}}</ref> The main difference between these processes is that anaerobic reactions produce [[methane]], while aerobic reactions do not (however, both reactions produce [[carbon dioxide]], [[water]], some type of residue, and a new [[biomass]]).<ref>{{Cite web|url=http://edepot.wur.nl/193543|title=Analytical Methods for Monitoring Biodegradation Processes of Environmentally Degradable Polymers|last=Van der Zee|first=Maarten|name-list-style=vanc|date=2011|access-date=2019-01-21|archive-date=2019-02-18|archive-url=https://web.archive.org/web/20190218014545/http://edepot.wur.nl/193543|url-status=live}}</ref> In addition, aerobic digestion typically occurs more rapidly than anaerobic digestion, while anaerobic digestion does a better job reducing the volume and mass of the material.<ref name=":2" /> Due to anaerobic digestion's ability to reduce the volume and mass of [[waste]] materials and produce a natural gas, anaerobic digestion technology is widely used for [[waste management]] systems and as a source of local, renewable energy.<ref>{{Cite journal|last=Klinkner|first=Blake Anthony|name-list-style=vanc|title=Anaerobic Digestion as a Renewable Energy Source and Waste Management Technology: What Must be Done for this Technology to Realize Success in the United States?|url=https://scholarship.law.umassd.edu/cgi/viewcontent.cgi?article=1027&context=umlr|journal=University of Massachusetts Law Review|volume=9|pages=68–96|year=2014|access-date=2018-09-23|archive-date=2020-06-29|archive-url=https://web.archive.org/web/20200629134555/https://scholarship.law.umassd.edu/cgi/viewcontent.cgi?article=1027&context=umlr|url-status=live}}</ref>

In the assimilation stage, the resulting products from biofragmentation are then integrated into [[microbial cell]]s.<ref name=":0" /> Some of the products from fragmentation are easily transported within the cell by [[membrane carrier]]s. However, others still have to undergo biotransformation reactions to yield products that can then be transported inside the cell. Once inside the cell, the products enter [[catabolic pathway]]s that either lead to the production of [[adenosine triphosphate]] (ATP) or elements of the [[anabolism|cells structure]].<ref name=":0" />

;Aerobic biodegradation equation
:C{{sub|polymer}} + O{{sub|2}} → C{{sub|residue}} + C{{sub|biomass}} + CO{{sub|2}} + H{{sub|2}}O

;Anaerobic biodegradation equation
:C{{sub|polymer}} → C{{sub|residue}} + C{{sub|biomass}} + CO{{sub|2}} + CH{{sub|4}} + H{{sub|2}}O