Amazonian mushroom eats plastic (Pestalotiopsis microspora)

Since the first plastic polymer polyurethane was discovered back in 1937 by I.G. Farben [3], Polyurethane, a synthetic  polymer derived from the condensation of polyisocyanate and polyol widely used as a base material in various industries [2], became more and more a concern for the amounts of this type of plastic produced by the industry and the pollution generated by its disposal.

Fortunately polyester polyurethane is one of the few types of plastics susceptible to degradation by natural sources, mainly biodegradation by microbial attack and enzyme degradation. However this wasn't that simple as this biodegradation required until now quite some effort to be achieved. Providentially, students of Yale University found a Fungus, Pestalotiopsis microspora, original from the Ecuadorian rain forest, able to decompose Polyurethane on a natural way.

Pestalotiopsis microspora was able to survive on an exclusive "diet" of polyurethane as it only carbon source, both in aerobic and anaerobic conditions (in the presence of air and without it). Other ways to decompose Polyurethane include the use of degrading enzymes as the esterase, derived from Comamonas acidovorans TB-35 [2], a gram negative bacteria resistant to most antibiotics.

RECYCLING FACTS AND THE PROBLEM OF PLASTIC WASTE

Only in the US post-consumer plastic waste for 2008 was estimated at 33.6 million tons and only 2.2 million tons (6.5%) were recycled being the other 2.6 million tons (7.7%) burned for energy, that give us a total of 28.9 million tons, or 85.5% discarded in landfills [4], where it may take between 100 to 400 years to decompose, or at least that's the latest estimate of how long scientists think the polyethylene’s polymer chains will take to start breaking under UV sunlight radiation, because plastic bags have been with us for only the last 50 years, so it's still uncertain how long it will really take.

PLASTIC FROM PLANTS NOT FROM PETROL

Further than that, for the very first time in history, Dutch scientists from the Utrecht University were able to produce the basic chemical blocks from which plastic is made, lower olefins, something that could help complete the green cycle of production/disposal that is so important nowadays to keep the ecologic challenges that our advance society faces using petrol derivatives.

OTHER USES OF PESTALOTIOPSIS MICROSPORA

But the use of this fungus is not limited to its role on being a possible biodegradating agent for plastics, Pestalotiopsis microspora fungus extracted from Taxus wallachiana, a small limb of Himalayan yew, produced taxol in mycelial culture, being its optimal production after 2-3 weeks in still culture at 23 degrees C.[5].

Taxol is a miotic inhibitor used to treat different types of cancer [6]. Taxol was discovered in 1967 by the US National Cancer Institute program when it was first extracted from the bark of Pacific yew tree (Taxus brevifolia) See image left. Under its commercial name Paclitaxel, Taxol is used to treat patients with lung, ovarian, breast, head and neck cancer, and advanced forms of Kaposi's sarcoma [6].

REFERENCES

[1] Biodegradation of polyester polyurethane by endophytic fungi. Russell JR, Huang J, Anand P, Kucera K, Sandoval AG, Dantzler KW, Hickman D, Jee J, Kimovec FM, Koppstein D, Marks DH, Mittermiller PA, Núñez SJ, Santiago M, Townes MA, Vishnevetsky M, Williams NE, Vargas MP, Boulanger LA, Bascom-Slack C, Strobel SA. Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.

[2] Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes. Nakajima-Kambe T, Shigeno-Akutsu Y, Nomura N, Onuma F, Nakahara T. Institute of Applied Biochemistry, University of Tsukuba, Ibaraki, Japan. Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520 Universidad Nacional San Antõnio Abad del Cusco, Peru Escuela Post Grado, Facultad de Biologia, Andes Amazon Guianas Herbario Vargas (CUZ), Cusco, Peru.

[3] Wikipedia article on Polyurethane

[4] "Energy and Economic Value of Non-recycled Plastics and Municipal Solid Wastes" at Journalist's Resource.org" via Wikipedia article on plastic

[5] Taxol from Pestalotiopsis microspora, an endophytic fungus of Taxus wallachiana.
Strobel G, Yang X, Sears J, Kramer R, Sidhu RS, Hess WM.
Department of Plant Pathology, Montana State University, Bozeman 59717, USA.

[6] Paclitaxel article via Wikipedia.