Review Challenges and opportunities in bioremediation of micro-nano plastics: A review Yuwen Zhou a , Manish Kumar b , Surendra Sarsaiya c , Ranjna Sirohi d , Sanjeev Kumar Awasthi a , Raveendran Sindhu e , Parameswaran Binod e , Ashok Pandey f , Nanthi S. Bolan g,h,i , Zengqiang Zhang a , Lal Singh b , Sunil Kumar b , Mukesh Kumar Awasthi a, ⁎ a College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China b CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur 440020, Maharashtra, India c Key Laboratory of Basic Pharmacology and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi, Guizhou, China d Department of Chemical and Biological Engineering, Korea University, Seoul, South Korea e Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Thiruvananthapuram, Kerala 695019, India f Centre for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow 226 001, India g School of Agriculture and Environment, The University of Western Australia, Perth, WA 6001, Australia h The UWA Institute of Agriculture, The University of Western Australia, Perth, WA 6001, Australia i School of Engineering, College of Engineering, Science and Environment, University of Newcastle, Callaghan, NSW 2308, Australia HIGHLIGHTS • Microbial degradation of micro-nano plastics (MNPs) is considered as clean technologies. • Biotic and abiotic factors of the environ- ment control the biodegradation of MNPs. • Microbial enzymatic machinery plays an important role in biodegradation of MNPs. • Implication of advanced molecular for biodegradation of MNPs is desirable. • Challenges and opportunities in biore- mediation of MNPs are reviewed. GRAPHICAL ABSTRACT abstract article info Article history: Received 27 June 2021 Received in revised form 14 August 2021 Accepted 18 August 2021 Available online 21 August 2021 Editor: Thomas Kevin V Rising level of micro-nano plastics (MNPs) in the natural ecosystem adversely impact the health of the environ- ment and living organisms globally. MNPs enter in to the agro-ecosystem, flora and fauna, and human body via trophic transfer, ingestion and inhalation, resulting impediment in blood vessel, infertility, and abnormal behav- iors. Therefore, it becomes indispensable to apply a novel approach to remediate MNPs from natural environ- ment. Amongst the several prevailing technologies of MNPs remediation, microbial remediation is considered as greener technology. Microbial degradation of plastics is typically influenced by several biotic as well as abiotic factors, such as enzymatic mechanisms, substrates and co-substrates concentration, temperature, pH, oxidative stress, etc. Therefore, it is pivotal to recognize the key pathways adopted by microbes to utilize plastic fragments as a sole carbon source for the growth and development. In this context, this review critically discussed the role of various microbes and their enzymatic mechanisms involved in biodegradation of MNPs in wastewater (WW) stream, municipal sludge, municipal solid waste (MSW), and composting starting with biological and toxicolog- ical impacts of MNPs. Moreover, this review comprehensively discussed the deployment of various MNPs Keywords: Micro-nano plastics (MNPs) Microplastics (MPs) Bioremediation Science of the Total Environment 802 (2022) 149823 ⁎ Corresponding author. E-mail addresses: mukesh_awasthi45@yahoo.com, mukeshawasthi85@nwafu.edu.cn (M.K. Awasthi). https://doi.org/10.1016/j.scitotenv.2021.149823 0048-9697/© 2021 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv