Plastic is a general term used for a wide range of high molecular weight organic polymers obtained mostly from the various hydrocarbon and petroleum derivatives. There is an ever-increasing trend towards the production and consumption of plastics due to their extensive industrial and domestic applications. However, a wide spectrum of these polymers is non-biodegradable with few exceptions. The extensive use of plastics, lack of waste management, and casual community behavior towards their proper disposal pose a significant threat to the environment. This has raised growing concerns among various stakeholders to devise policies and innovative strategies for plastic waste management, use of biodegradable polymers especially in packaging, and educating people for their proper disposal. Current polymer degradation strategies rely on chemical, thermal, photo, and biological procedures. In the presence of proper waste management strategies coupled with industrially controlled biodegradation facilities, the use of biodegradable plastics for some applications such as packaging or health industry is a promising and attractive option for economic, environmental, and health benefits. This review highlights the classification of plastics with special emphasis on biodegradable plastics and their rational use, the identified mechanisms of plastic biodegradation, the microorganisms involved in biodegradation, and the current insights into the research on biodegradable plastics. The review has also identified the research gaps in plastic biodegradation followed by future research directions.

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Biochar enhances soil fertility by improving the soil physical, chemical and microbiological properties. The aim of this study was to investigate the impact of corn cob-derived biochar on soil enzymatic activity, organic carbon, aggregate stability and soil microbial biomass carbon under drought stress. Biochar was prepared from crushed corn cobs pyrolyzed at 300 °C and 400 °C and applied at a ratio of 1% (w/w) and 3% (w/w) filled in pots. In each pot, three field capacity (FC) levels, i.e., 100, 70 and 40%, were maintained gravimetrically. Results showed that biochar application improved the growth (plant height and root length) and relative water content in maize leaves under drought stress, while it reduced electrolyte leakage compared to a control treatment. Aggregate stability was significantly (p ≤ 0.05) higher in biochar amended soil. Moreover, microbial biomass carbon and soil water also increased under drought stress at 70% FC and 40% FC, respectively, where 3% w/w (400 °C) biochar was applied. Among enzymes, β-glucosidase and alkaline phosphatase activity were improved with biochar application. The maximum organic carbon (240%, 246% and 249%, 254% more than control) was calculated in soils where 3% biochar pyrolyzed at 400 °C and 300 °C was mixed with soil, respectively. Similarly, the carbon pool index (CPI) and carbon management index (CMI) were also higher in biochar-amended soil as compared to control treatment. Conclusively, biochar amendment could effectively improve soil quality and maize growth under drought stress.

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