Preliminary Studies on the Microbial Degradation of Plastic Waste Using <i>Aspergillus niger</i> and <i>Pseudomonas</i> sp.

Abstract

The possibility of microbial degradation of plastic waste was investigated by isolating microorganisms present in dumpsite containing low-density polyethylene (LDP). Aspergillus niger (fungi) and Pseudomonas sp. (bacteria) were identified and subsequently used to biodegrade plastic waste. The medium was made up of 0.2 g of MgSO 4 , 1.0 g of KH 2 PO 4 , 1.0 g of K 2 HPO 4 , 1.0 g of NH 4 NO 3 , 0.02 g of CaCl 2 , 0.05 g of FeCl 3 in 1000 ml water. 10 ml of the medium containing the bacteria and/or fungi was poured into test tubes and 0.1 g of the plastic sample (Pure water sachet) pre-treated with ethanol was introduced into the tubes. The pH of the medium was adjusted to 7.2, 5.4 and 6.0 for Pseudomonas sp., Aspergillus niger and the mixed culture respectively. Each experiment was carried out aerobically at room temperature and incubated on a rotary shaker at 120 rpm. The weight loss in each experiment was monitored at 10 days interval for 60 days. The total weight loss after 60 days was 7.2%, 12.4%, 15% for degradation with Pseudomonas sp., Aspergillus niger and the mixed culture respectively. From this study it can be inferred that Pseudomonas sp. and Aspergillus niger have the ability to degrade plastics. It can also be inferred that Aspergillus niger degraded plastics better than Pseudomonas sp. and there was synergy between the two microorganisms since the mixed culture gave a higher degradation.

Degradation of Polyethylene Using Bacteria from Waste Dump Sites in Obio/Akpor Local Government Area in Rivers State, Nigeria

“…According to the study of Robert et al [17], the consortium of five strains containing Pseudomonas and Bacillus species grew synergistically in the presence of polyethylene terephthalate and the cleavage product bis (2-hydroxy ethyl) terephthalic acid (BHET) as sole source of carbon. This is also in line with the study of Ogunbayo et al, [18] in which consortium of microorganisms was reported to have higher degradation efficacy. The higher degradation by consortium of these organisms can be attributed to the synergistic activity of these microorganisms in degradation of polyethylene.…”

Biodegradation of plastic materials obtained from solid waste dumpsites in Nigeria, using native bacterial strains

“…All the representative bacterial isolates (n= 54) were used for the plastic biodegradation assay for periods of 15, 30, 45, and 60 d, using the method described by Ogunbayo et al, (2019) with slight modifications. The collected plastics bags and bottles were cut into tiny square strips (1×1 cm) using a sterile pair of table scissors.…”

“…The same steps were repeated for all the treated samples in duplicates. The percentage of degradation (%) of each strip of bags and bottles by the tested bacteria was determined through calculating the % of weight loss of the plastic materials using the following formula of Ogunbayo et al, (2019):…”

Isolation and Identification of Polyethylene Terephthalate Degrading Bacteria from Shatt Al-Arab and Sewage Water of Basrah City

“…The process of a polymer's chemical structure changing from a more complex to a simpler one under the influence of several biological agents, such as bacteria, fungi, and various atmospheric microorganisms, is known as biodegradation 6 . More than 90 genera of microorganisms that break down polymers such as: Actinomycetes, Thermoactinomyces, Azotobacter, Alcaligenes, Streptomyces, Mycobacterium, Micromonospora, Flavobacterium, Escherichia, Rhodococcus, Streptococcus, Klebsiella, Nocardia, Pseudomonas, Comamonas, and Staphylococcus 7,8 . The plastic biodegradation mechanism involves many levels.…”