Currently, microplastic is considered a major concern worldwide and noteworthy among the researcher and authorities. Microplastic has spread ubiquitously in the environment, particularly in the aquatic system, due to its tiny size. This microplastic is indispensable to treat since it poses hazards to marine life, human, and soil-plant. This research paper aims to investigate the performance of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polystyrene (PS) microplastic in a closed system. This microplastic has been biodegraded in the batch culture system using a colony of bacteria acquired from landfill leachate as a carbon source. The percentage of microplastic removal after the incubation period (7, 14, and 21 days) was determined. Moreover, the analysis of chemical properties, morphology surfaces of microplastic, and ammonia-nitrogen for each batch culture were evaluated. The findings revealed that all microplastic could be degraded after the incubation period. However, PE microplastic showed the highest percentage weight loss (8.8%) compared with other microplastic. Analysis by Fourier transform infrared spectroscopy demonstrates that the chemical structure of each polymer has changed, which involved the formation of C=O in PP and PE. The observation by scanning electron microscope indicated the alteration on the surface in each microplastic, such as fractures and rough surfaces. Besides that, PP microplastic indicated the maximum ammonia-nitrogen removal after 16 days incubation period (97.41%). This method can be applied in the leachate treatment system to achieve a higher quality of effluent. Furthermore, extending the incubation period for microplastic biodegradation can attain better optimal results in further research.

• Abayomi, O., Range, P., Ghouti, M., Obbard, J., Almeer, S., & Hamadou, R. (2017). Microplastics in coastal environments of the Arabian Gulf. Marine Pollution Bulletin, 124(1), 181-188. https://doi.org/10.1016/j.marpolbul.2017.07.011

• APHA. (2005). Standard methods for the examination of water and wastewater (Vol. 21). American Public Health Association.

• Auta, H., Emenike, C., & Fauziah, S. (2017). Screening of Bacillus strains isolated from mangrove ecosystems in Peninsular Malaysia for microplastic degradation. Environmental Pollution, 231, 1552-1559. https://doi.org/10.1016/j.envpol.2017.09.043

• Bai, Z., Wang, N., & Wang, M. (2021). Effects of microplastics on marine copepods. Ecotoxicology and Environmental Safety, 217, 1-12. https://doi.org/10.1016/j.ecoenv.2021.112243

• Bailey, R. (2018). Phases of the bacterial growth curve. ThoughtCo Publishing.

• Belone, M., Kokko, M., & Sarlin, E. (2021). Degradation of common polymers in sewage sludge purification process developed for microplastic analysis. Environmental Pollution, 269, 1-8. https://doi.org/10.1016/j.envpol.2020.116235

• Bråte, I., Blázquez, M., Brooks, S., & Thomas, K. (2018). Weathering impacts the uptake of polyethylene microparticles from toothpaste in Mediterranean mussels (M. galloprovincialis). Science of the Total Environment, 626, 1310-1318. https://doi.org/10.1016/j.scitotenv.2018.01.141

• Chamas, A., Moon, H., Zheng, J., Qiu, Y., Tabassum, T., Jang, J. H., Abu-Omar, M., Scott, S. L., & Suh, S. (2020). Degradation rates of plastics in the environment. ACS Sustainable Chemistry & Engineering, 8(9), 3494-3511. https://doi.org/10.1021/acssuschemeng.9b06635

• Chinaglia, S., Tosin, M., & Degli-Innocenti, F. (2018). Biodegradation rate of biodegradable plastics at molecular level. Polymer Degradation and Stability, 147, 237-244. https://doi.org/10.1016/j.polymdegradstab.2017.12.011

• de Oliveira, T. A., Barbosa, R., Mesquita, A. B., Ferreira, J. H., de Carvalho, L. H., & Alves, T. S. (2020). Fungal degradation of reprocessed PP/PBAT/thermoplastic starch blends. Journal of Materials Research and Technology, 9, 2338-2349. https://doi.org/10.1016/j.jmrt.2019.12.065

• Emadian, S., Onay, T., & Demirel, B. (2017). Biodegradation of bioplastics in natural environments. Waste Management, 59, 526-536. httpss://doi.org/10.1016/j.wasman.2016.10.006

• Farzi, A., Dehnad, A., & Fotouhi, A. (2019). Biodegradation of polyethylene terephthalate waste using Streptomyces species and kinetic modeling of the process. Biocatalysis and Agricultural Biotechnology, 17, 25-31. https://doi.org/10.1016/j.bcab.2018.11.002

• Gewert, B., Plassmann, M., & MacLeod, M. (2015). Pathways for degradation of plastic polymers floating in the marine environment. Environmental Science Processes & Impacts, 17(9), 1513-1521. https://doi.org/10.1039/c5em00207a

• Gras, L., Plaats, R., Wielen, P., Bauerlein, P., & Husman, A. (2021). Riverine microplastic and microbial community compositions: A field study in the Netherlands. Water Research, 192, Article 116852. https://doi.org/10.1016/j.watres.2021.116852

• Habib, S., Iruthayam, A., Shukor, M., Alias, S., Smykla, J., & Yasid, N. (2020). Biodeterioration of untreated polypropylene microplastic particles by Antarctic bacteria. Polymers, 12(11), Article 2616. https://doi.org/10.3390/polym12112616

• Hadiyanto, H., Khoironi, A., Dianratri, I., Suherman, S., Muhammad, F., & Vaidyanathan, S. (2021). Interactions between polyethylene and polypropylene microplastics and Spirulina sp. microalgae in aquatic systems. Heliyon, 7(8), Article e07676. https://doi.org/10.1016/j.heliyon.2021.e07676

• Jeon, J. M., Park, S. J., Choi, T. R., Park, J. H., Yang, Y. H., & Yoon, J. J. (2021). Biodegradation of polyethylene and polypropylene by Lysinibacillus species JJY0216 isolated from soil grove. Polymer Degradation and Stability, 191, Article 109662. https://doi.org/10.1016/j.polymdegradstab.2021.109662

• Kasmuri, N., & Lovitt, R. (2018). Enriching the culture of ammonia oxidizing bacteria from soil and fishpond with bio-filters. Journal of Engineering Science and Technology, 13, 1562-1572.

• Li, J., Liu, H., & Chen, J. P. (2018). Microplastics in freshwater systems: A review on occurrence, environmental effects, and methods for microplastics detection. Water Research, 137, 362-374. https://doi.org/10.1016/j.watres.2017.12.056

• Maier, R. (2009). Bacterial growth. In R. Maier, I. Pepper, & C. Gerba (Eds.), Environmental microbiology (pp. 37-54). Academic Press. https://doi.org/10.1016/B978-0-12-370519-8.X0001-6

• Merck. (2021). IR spectrum table & chart. Merck.

• Montazer, Z., Najafi, M., & Levin, D. (2020). Challenges with verifying microbial degradation of polyethylene. Polymers, 12(1), Article 123. https://doi.org/10.3390/polym12010123

• Paço, A., Duarte, K., da Costa, J. P., Santos, P. S. M., Pereira, R., Pereira, M. E., Freitas, A. C., Duarte, A. C., & Rocha-Santos, T. A. P. (2017). Biodegradation of polyethylene microplastics by the marine fungus Zalerion maritimum. Science of the Total Environment, 586, 10-15. https:// doi.org/10.1016/j.scitotenv.2017.02.017

• Park, J., & Dho, H. (2018). Analysis of A2O process in wastewater using statistical technique. International Journal of Civil Engineering and Technology (IJCIET), 9(8), 120-129.

• Pegado, T., Schmid, K., Winemiller, K., Chelazzi, D., Cincinelli, A., Dei, L., & Giarrizzo, T. (2018). First evidence of microplastic ingestion by fishes from the Amazon River estuary. Marine Pollution Bulletin, 133, 814-821. https://doi.org/10.1016/j.marpolbul.2018.06.035

• Plastics, E. (2020). Plastics - The facts 2020 an analysis of European plastics production, demand and waste data. PlasticsEurope.

• Prata, J. (2018). Microplastics in wastewater: State of the knowledge on sources, fate and solutions. Marine Pollution Bulletin, 129(1), 262-265. https://doi.org/10.1016/j.marpolbul.2018.02.046

• Qi, Y., Yang, X., Pelaez, A. M., Lwanga, E. H., Beriot, N., Gertsen, H., Garbeva, P., & Geissen, V. (2018). Macro- and micro-plastics in soil-plant system: Effects of plastic mulch film residues on wheat (Triticum aestivum) growth. Science of the Total Environment, 645, 1048-1056. https://doi.org/10.1016/j.scitotenv.2018.07.229

• Qin, K. (2015). Cometabolic biodegradation of halogenated aliphatic hydrocarbons by ammonia-oxidizing microorganisms naturally associated with wetland plant roots (Doctoral dissertation). Wright State University, USA.

• Ragusa, A., Svelato, A., Santacroce, C., Catalano, P., Notarstefano, V., Carnevali, O., Papa, F., Rongioletti, M. C. A., Baiocco, F., Draghi, S., D’Amore, E., Rinaldo, D., Matta, M., & Giorgini, E. (2021). Plasticenta: First evidence of microplastics in human placenta. Environment International, 146, Article 106274. https://doi.org/10.1016/j.envint.2020.106274

• Ramsperger, A. F. R. M., Stellwag, A. C., Caspari, A., Fery, A., Lueders, T., Kress, H., Loder, M. G. J., & Laforsch, C. (2020). Structural diversity in early-stage biofilm formation on microplastics depends on environmental medium and polymer properties. Water, 12(11), Article 3216. http://doi.org/10.3390/w12113216

• Reinold, S., Herrera, A., Saliu, F., Gonz´alez, C., Martinez, I., Lasagni, M., & G´omez, M. (2021). Evidence of microplastic ingestion by cultured European sea bass. Marine Pollution Bulletin, 168, 1-10. https://doi.org/10.1016/j.marpolbul.2021.112450

• Rogers, K. (2020). Bacteria: Life-form. Britannica.

• Shah, A., Hasan, F., Hameed, A., & Ahmed, S. (2008). Biological degradation of plastics: A comprehensive review. Biotechnology Advances, 26(3), 246-265. http://doi.org/10.1016/j.biotechadv.2007.12.005

• Silva, A., Prata, J., Duarte, A., Soares, A., Barcelo, D., & Santos, T. (2021). Microplastics in landfill leachates: The need for reconnaissance studies and remediation technologies. Case Studies in Chemical and Environmental Engineering, 3, 1-6. https://doi.org/10.1016/j.cscee.2020.100072

• Silva, P., & Sousa, F. (2021). Microplastic pollution of Patos Lagoon, south of Brazil. Environmental Challenges, 4, 1-11. https://doi.org/10.1016/j.envc.2021.100076

• Sudhakar, J., Arkatkar, A., Doble, M., Bhaduri, S., & Uppara, P. (2008). Biodegradation of polyethylene and polypropylene. Indian Journal of Biotechnology, 07(1), 9-22.

• Sun, Y., Ren, X., Rene, E. R., Wang, Z., Zhou, L., Zhang, Z., & Wang, Q. (2021). The degradation performance of different microplastics and their effect on microbial community during composting process. Bioresource Technology, 332, 1-9. https://doi.org/10.1016/j.biortech.2021.125133

• Taghavi, N., Singhal, N., Zhuang, W. Q., & Baroutian, S. (2021). Degradation of plastic waste using stimulated and naturally occurring microbial strains. Chemosphere, 263, 1-14. https://doi.org/10.1016/j.chemosphere.2020.127975

• Tarmizi, N. A. A., Kasmuri, N., & Kasmuri, N. H. (2019). Micro-plastic characteristics and removal of ammonia-nitrogen in batch culture. International Journal of Engineering and Advanced Technology (IJEAT), 9(1), 5683-5693. https://doi.org/10.35940/ijeat.A3047.109119

• Thermoscientific. (2018). Phenom XL desktop SEM: Desktop SEM for large samples and automation. Thermo Fisher Scientific Inc.

• Vaughan, R., Turner, S., & Rose, N. (2017). Microplastics in the sediments of a UK urban lake. Environmental Pollution, 229, 10-18. https://doi.org/10.1016/j.envpol.2017.05.057

• Wilkes, R., & Aristilde, L. (2017). Degradation and metabolism of synthetic plastics and associated products by Pseudomonas sp.: Capabilities and challenges. Journal of Applied Microbiology, 123(3), 582-593. https://doi.org/10.1111/jam.13472

• Zhang, Y., Kang, S., Allen, S., Allen, D., Gao, T., & Sillanpää, M. (2020). Atmospheric microplastics: A review on current status and perspectives. Earth-Science Reviews, 203, 1-15. https://doi.org/10.1016/j.earscirev.2020.103118

• Zong, X., Zhang, J., Zhu, J., Zhang, L., Jiang, L., Yin, Y., & Guo, H. (2021). Effects of polystyrene microplastic on uptake and toxicity of copper and cadmium in hydroponic wheat seedlings (Triticum aestivum L.). Ecotoxicology and Environmental Safety, 217, 1-9. https://doi.org/10.1016/j.ecoenv.2021.112217