African Scientists find fungi and bacteria that degrades plastics

Image credit: https://oceans.taraexpeditions.org/en/m/science/news/bacterial-degradation-of-synthetic-plastics/ 

In a recent paper published by PLOS ONE, Researchers from Kenya have isolated and identified fungal and bacterial species capable of degrading plastics. The microorganisms were isolated from the Dandora dumpsite in Nairobi, the capital city of Kenya.

Tons of plastics are produced and used around the world. They are used as packaging materials for chemicals, food and carrying groceries almost in all countries.  Plastics are also used in covering and insulating electrical and electronic appliances. The use of plastics in the construction industries is not negligible as plastic is used for seals, floor coverings cables, and pipes. The extensive application of plastics is because plastics are cost-effective, resistant to water and microorganisms, durable and corrosion resistant.

Commonly used plastics include polyethylene, polystyrene, and polypropylene. These plastics are non-biodegradable hence cause environmental pollution with great interference in the ecosystem. 

The plastic pollution is of global concern for many nations and environmental agencies calling for the finding of better measures to curb the plastic menace. One promising solution is the use of certain microorganisms with the capability of degrading such plastics. In this study, researchers including Christabel Ndahebwa Muhonja of the Pan African University Institute of Science, Technology, and Innovation, Nairobi, Kenya have isolated and identified bacteria and fundi with the capability of degrading the type of plastic called low-density polyethylene (LDPE) which is known for its non-biodegradability.

According to the paper, the researchers incubated LDPE sheets with fungal and bacterial inoculums isolated from the Dandora dumpsite. The incubations were made at two different temperatures (28 & 37 ⁰C for sixteen weeks after which the extent of degradation was evaluated based on weight loss, spectroscopy, and chromatographic techniques. The isolates were also identified by the use of 16S and 18S ribosomal DNA for bacteria and fungi, respectively.

The findings of the study show that after sixteen weeks of incubation, weight loss of samples was recorded, and new functional groups which have been previously attributed to hydrocarbon degradation were identified, implying that LDPE was degraded. Bacteria were identified to be from the genera Pseudomonas, Bacillus, Brevibacillus, Cellulosimicrobium, Lysinibacillus while fungi were of the genus Aspergillus. The study also found out isolates of the genera Bacillus and Aspergillus showed better degrading ability on LDPE.

While the use of microorganisms to degrade plastics seems promising, there is the need for more research to identify better degraders and or find ways of enhancing them to degrade plastics in an effective and efficient manner.

Read full paper here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0198446

Journal Article Reference: Muhonja CN, Makonde H, Magoma G, ImbugaM (2018) Biodegradability of polyethylene by bacteria and fungi from Dandora dumpsite Nairobi-Kenya. PLoS ONE 13(7): e0198446. https://doi.org/10.1371/journal.pone.0198446

Copyrights: https://creativecommons.org/licenses/by/4.0/