Pleomorphomonas diazotrophica sp. nov., an endophytic N-fixing bacterium isolated from root tissue of Jatropha curcas L.

A novel aerobic, non-motile, pleomorphic, Gram-negative and nitrogen-fixing bacterial strain, designated R5-392(T), was isolated from surface-sterilized root tissue of Jatropha curcas. The organism grew optimally at 30 °C in media containing 1 % (w/v) NaCl and at pH 6.0-8.0. The predominant ubiquinone was Q-10 and the major fatty acids were C18 : 1ω7c/C18 : 1ω6c, C16 : 0 and C19 : 0 cyclo ω8c. The DNA G+C content was 63.2 mol%. Analysis of the 16S rRNA gene sequence suggested that strain R5-392(T) is affiliated with the order Rhizobiales within the class Alphaproteobacteria and is most closely related to Pleomorphomonas oryzae F-7(T) (98.8 % similarity) and Pleomorphomonas koreensis Y9(T) (98.3 % similarity). Analysis of partial nifH gene sequences also revealed a monophyletic lineage within the class Alphaproteobacteria, and strain R5-392(T) was most closely related to P. oryzae F-7(T) (98 %). Highest nitrogenase activity was detected in the presence of low-level organic nitrogen or in the presence of nitrogenase co-factors (Fe/Mo) in N-free media. Phenotypic and chemotaxonomic data suggest that strain R5-392(T) represents a novel species within the genus Pleomorphomonas, for which the name Pleomorphomonas diazotrophica sp. nov. is proposed. The type strain is R5-392(T) ( = KACC 16233(T) = DSM 25022(T)).

Green Recycling Methods to Treat Lithium-Ion Batteries E-Waste: A Circular Approach to Sustainability.

E-waste generated from end-of-life spent lithium-ion batteries (LIBs) is increasing at a rapid rate owing to the increasing consumption of these batteries in portable electronics, electric vehicles, and renewable energy storage worldwide. On the one hand, landfilling and incinerating LIBs e-waste poses environmental and safety concerns owing to their constituent materials. On the other hand, scarcity of metal resources used in manufacturing LIBs and potential value creation through the recovery of these metal resources from spent LIBs has triggered increased interest in recycling spent LIBs from e-waste. State of the art recycling of spent LIBs involving pyrometallurgy and hydrometallurgy processes generates considerable unwanted environmental concerns. Hence, alternative innovative approaches toward the green recycling process of spent LIBs are essential to tackle large volumes of spent LIBs in an environmentally friendly way. Such evolving techniques for spent LIBs recycling based on green approaches, including bioleaching, waste for waste approach, and electrodeposition, are discussed here. Furthermore, the ways to regenerate strategic metals post leaching, efficiently reprocess extracted high-value materials, and reuse them in applications including electrode materials for new LIBs. The concept of "circular economy" is highlighted through closed-loop recycling of spent LIBs achieved through green-sustainable approaches.

A review on the recycling of spent lithium-ion batteries (LIBs) by the bioleaching approach.

This review discusses the latest trend in recovering valuable metals from spent lithium-ion batteries (LIBs) to meet the technological world's critical metal demands. Spent LIBs are a secondary source of valuable metals such as Li (5%-7%), Ni (5%-10%), Co (5%-25%), Mn (5-11%), and non-metal graphite. Recycling is essential for the battery industry to extract valuable critical metals from secondary sources to develop new and novel high-tech LIBs for various applications such as eco-friendly technologies, renewable energy, emission-free electric vehicles, and energy-saving lightings. LIB waste is currently undergoing high-temperature pyrometallurgical or hydrometallurgical processes to recover valuable metals, and these processes have proven to be successful and feasible. These methods, however, are not preferable due to the difficulties in controlling the process, secondary waste produced, high operational cost, and high risk of scaling up. Biotechnological approaches can be promising alternatives to pyrometallurgical and hydrometallurgical technologies in metal recovery from LIB waste. Microbiological metal dissolution or bioleaching has gained popularity for metal extraction from ores, concentrates, and recycled or residual materials in recent years. This technology is eco-friendly, safe to handle, and reduces operating costs and energy demands. The pre-treatment process (material preparation), microorganisms used in the bioleaching of LIBs, factors influencing the bioleaching process, methods of enhancing the leaching efficiency, regeneration of electrode materials, and future aspects have been discussed in detail.