Biodegradable plastic


 * 1) Search for studies on Pubmed.

=Studies about bacteria/fungi=


 * 1) Brunner I, Fischer M, Rüthi J, Stierli B, Frey B. Ability of fungi isolated from plastic debris floating in the shoreline of a lake to degrade plastics. PLoS One. 2018 Aug 22;13(8):e0202047. doi: 10.1371/journal.pone.0202047. eCollection 2018. PubMed PMID: 30133489; PubMed Central PMCID: PMC6104954. Web page.
 * 2) The tests showed that none of the strains were able to degrade polyethylene. However, four strains were able to degrade polyurethane, the three litter-saprotrophic fungi Cladosporium cladosporioides, Xepiculopsis graminea, and Penicillium griseofulvum and the plant pathogen Leptosphaeria sp.
 * 3) Peng R, Xia M, Ru J, Huo Y, Yang Y. [Microbial degradation of polyurethane plastics]. Sheng Wu Gong Cheng Xue Bao. 2018 Sep 25;34(9):1398-1409. doi: 10.13345/j.cjb.170532. Review. Chinese. PubMed PMID: 30255674. Web page.
 * 4) Roohi, Bano K, Kuddus M, Zaheer MR, Zia Q, Khan MF, Ashraf GM, Gupta A, Aliev G. Microbial Enzymatic Degradation of Biodegradable Plastics. Curr Pharm Biotechnol. 2017;18(5):429-440. doi: 10.2174/1389201018666170523165742. Review. PubMed PMID: 28545359. Web page.
 * 5) Abstract: BACKGROUND: The renewable feedstock derived biodegradable plastics are important in various industries such as packaging, agricultural, paper coating, garbage bags and biomedical implants. The increasing water and waste pollution due to the available decomposition methods of plastic degradation have led to the emergence of biodegradable plastics and biological degradation with microbial (bacteria and fungi) extracellular enzymes. The microbes utilize biodegradable polymers as the substrate under starvation and in unavailability of microbial nutrients. Microbial enzymatic degradation is suitable from bioremediation point of view as no waste accumulation occurs.
 * 6) METHODS: It is important to understand the microbial interaction and mechanism involved in the enzymatic degradation of biodegradable plastics under the influence of several environmental factors such as applied pH, thermo-stability, substrate molecular weight and/or complexity. To study the surface erosion of polymer film is another approach for hydrolytic degradation characteristion.
 * 7) RESULTS: The degradation of biopolymer is associated with the production of low molecular weight monomer and generation of carbon dioxide, methane and water molecule. This review reported the degradation study of various existing biodegradable plastics along with the potent degrading microbes (bacteria and fungi). Patents available on plastic biodegradation with biotechnological significance is also summarized in this paper.
 * 8) Urbanek AK, Rymowicz W, Mirończuk AM. Degradation of plastics and plastic-degrading bacteria in cold marine habitats. Appl Microbiol Biotechnol. 2018 Sep;102(18):7669-7678. doi: 10.1007/s00253-018-9195-y. Epub 2018 Jul 11. Review. PubMed PMID: 29992436; PubMed Central PMCID: PMC6132502. Web page.
 * 9) Abstract: Synthetic plastics present in everyday materials constitute the main anthropogenic debris entering the Earth's oceans. The oceans provide important and valuable resources such as food, energy, and water. They are also the main way of international trade and the main stabilizer of the climate. Hence, changes in the marine ecosystem caused by anthropogenic influences such as plastic pollution can have a dramatic impact on a global scale. Although the problem of plastics still remains unsolved, different ways are being considered to reduce their impact on the environment. One of them is to use microorganisms capable of degradation of plastic. A particularly interesting area is the application of microorganisms isolated from cold regions in view of their unique characteristics. Nevertheless, the interactions between plastic and microorganisms are still poorly known. Here, we present a review of current knowledge on plastic degradation and plastic-microorganism interactions in cold marine habitats. Moreover, we highlight the advantages of microorganisms isolated from this environment for eliminating plastic waste from ecosystems.
 * 10) Due to the fact that most petrochemical plastics are not biodegradable, new biodegradable plastics (BPs) have been developed and some of them have already been introduced to the market. Nowadays, there are many products available (bottles, packages) that are made from biodegradable plastics such as poly(lactic acid) (PLA), poly(ε-caprolactone) (PCL), poly(butylene succinate) (PBS), or poly(butylene succinate-co-butylene adipate) (PBSA) (Fig. 1). Biodegradable plastics, which may be classified as being either bio-based or petrochemical-based (Song et al. 2009), can be degraded in an eco-friendly way by microorganisms, resulting in the fragmentation of material via microbial enzymatic activities and bond cleavage (Pathak and Navneet 2017).
 * 11) Zheng Y, Yanful EK, Bassi AS. A review of plastic waste biodegradation. Crit Rev Biotechnol. 2005 Oct-Dec; 25(4):243-50. Review. PubMed PMID: 16419620. Web page.
 * 12) Abstract: This review looks at the technological advancement made in the development of more easily biodegradable plastics and the biodegradation of conventional plastics by microorganisms. Additives, such as pro-oxidants and starch, are applied in synthetic materials to modify and make plastics biodegradable. Recent research has shown that thermoplastics derived from polyolefins, traditionally considered resistant to biodegradation in ambient environment, are biodegraded following photo-degradation and chemical degradation. Thermoset plastics, such as aliphatic polyester and polyester polyurethane, are easily attacked by microorganisms directly because of the potential hydrolytic cleavage of ester or urethane bonds in their structures.

=Biodegradable products=

When looking for biodegradable plastics make sure they are made from these plastics: poly(lactic acid) (PLA), poly(ε-caprolactone) (PCL), poly(butylene succinate) (PBS), or poly(butylene succinate-co-butylene adipate) (PBSA).


 * 1) Tableware made from wheat bran. But how much of the product is actually plastic and actually biodegradable?
 * 2) Edible plates made from wheat bran.

=My own experiment=

Staring in May 2019 I put out a compostable plastic fork in ground contact to see if it would degrade, and how fast. It is exposed to weather 24/7.

Update June 2022: It has been 3 years and the plastic has not degraded a bit, nor has it been made brittle by UV rays of the sun. The plastic is in near-perfect condition and could easily be used to eat food. It is slightly dirty.