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Background: Extremophiles are a hot topic in the field of biotechnology for their immense potential and applications in multiple industries. Objectives: The present review aims to sum up the potential applications of alkalophilic protease-producing bacteria and their optimized growth requirement. The isolation, characterization, and optimization of various isolates (especially of genus Bacillus) from different harsh niches, including soil samples from deserts and soil having decaying matters, wastewaters from industries, soda lakes, and alkaline springs have been reported in this review. Methodology: All the relevant papers published from 2013-2020 were looked over numerous sources like Google Scholar, Medline, PubMed, Research Gate, Science Direct, Scopus and Web of Science. Results: Most of the microbial life found in extreme alkaline habitats are found to form a variety of enzymes and an array of other substances of biotechnological interests. These enzymes, especially proteases, are exploited in industries globally because of their ability to withstand rigorous industrial reactions and conditions. Conclusion: Though a number of alkalophilic protease-producing bacteria have been isolated, still a large number of these micro-organisms are unidentified. The current demand for biotechnological products from them appeals to the need for isolation of unidentified bacteria.

The process of paper production requires a huge quantity of water and energy and in turn contributes a number of effluents in the form of phenolics, toxic organic compounds and heavy metals in wastewater (leachate). The present investigation was aimed to assess the toxic effects of leachate on liver micro-architecture and heavy metal elements of the liver. Eighteen (18) healthy male Wistar rats (240 ± 10g) were selected and acclimatized prior to experimental treatment. These rats were randomly divided into three groups viz, Control group (received 4ml/ kg normal saline), Group 1 (4ml/ kg leachate) and Group 2 (4ml/ kg 1:10 diluted leachate). All the animals were dissected and liver tissues were collected and processed accordingly after 24 h of leachate treatment. High level of cadmium and chromium were found in Group 1 as compared to the control group upon liver metal contents analysis found out by flame atomic absorption spectrometer. A clear disruption of micro-architecture of the liver, congested sinusoids, damaged central vein, and perturbed morphology was observed in Group-1 as revealed by H & E staining. Moreover, loss of polarity, congestion, and disruption of hepatocytes and pronounced vacuolization in the cytoplasm was observed in Group 2 compared to control sections. On the basis of above findings, it can be concluded that paper industry leachate is highly toxic and its intraperitoneal injection results in hepatotoxicity that not only affects the hepatic micro-architecture but also results in perturbed liver metal contents. Therefore, proper treatment of such wastewater is required before its disposal.