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Abstract The increase in the global population has led to a substantial increase in the demand for food supply as well as food manufacturing industries that regularly produce large amounts of food waste. Agro-industrial waste has attracted tremendous attention all over the world since ancient times, such waste is usually dumped or burned and poses a threat to human health and the environment, which has always been a matter of serious concern. However, food waste is a major source of complex carbohydrates, proteins, lipids, vitamins, minerals, fibers, and helps in the manufacture of raw materials for a variety of industrial purposes such as the production of biofuels, enzymes, bioactive compounds, biodegradable plastics, surfactants. Hence it is necessary to convert food waste into value-added products that reduce environmental problems. The present review paper attempts to outline and analyze the potential of agro-industrial residues as cost-effective substrates to produce the enzyme amylase using a wide range of microbial strains. Graphical Abstract

Constructed wetlands (CWs) have emerged as robust alternatives to traditional wastewater treatment technologies. The efficacy of CWs centers on the intricate interplay of factors, including plant species, substrate attributes, soil conditions, microbial consortia, and operational variables. Microorganisms, the cornerstone of CWs, have a significant influence on mineralization and pollutant mitigation processes. Microbial assemblies within CWs exhibit dynamic responses by adapting novel mechanisms. Here, Proteobacteria possess the ability to efficiently fix nitrogen through innovative pathways, including denitrifying anaerobic methane oxidation (DAMO) and sulfur autotrophic denitrification (SAD). Furthermore, Actinobacteria, Firmicutes, and Gemmatimonadetes have been thoroughly investigated to emphasize their significance in phosphate metabolism. These microorganisms may adapt to various metabolic pathways due to seasonal changes, plant diversity, wastewater composition, and system configuration. On the other hand, microorganisms have been proven to be effective in removing heavy metals in constructed wetlands. Various techniques such as biosorption, transformation, and biomineralization are widely used for this purpose. Therefore, it is essential to conduct a comprehensive investigation of the structure and diversity of microbial communities within constructed wetlands to gain a complete understanding of the system's performance and optimization strategies. This review provides a detailed analysis of microbial studies conducted in constructed wetlands and aimed to understand the mechanisms involved in pollutant removal and the influence of various factors on microbial community prevalence. The outcomes of this review not only deepen our comprehension of CWs and ecosystems, but also provide a basis for knowledgeable choices in their planning and execution, ultimately leading to the responsible stewardship of water resources.

The cold adapted microorganisms, psychrophiles/psychrotolerants, go through several modifications at cellular and biochemical levels to alleviate the influence of low temperature stress conditions. The low temperature environments depend on these cold adapted microorganisms for various ecological processes. The ability of the microorganisms to function in cold environments depends on the strategies directly associated with cell metabolism, physicochemical constrains, and stress factors. Pseudomonas is one among such group of microorganisms which is predominant in cold environments with a wide range of ecological and biotechnological applications. Bioformulations of Pseudomonas spp., possessing plant growth promotion and biocontrol abilities for application under low temperature environments, are well documented. Further, recent advances in high throughput sequencing provide essential information regarding the prevalence of Pseudomonas in rhizospheres and their role in plant health. Cold adapted species of Pseudomonas are also getting recognition for their potential in biodegradation and bioremediation of environmental contaminants. Production of enzymes and bioactive compounds (primarily as an adaptation mechanism) gives way to their applications in various industries. Exopolysaccharides and various biotechnologically important enzymes, produced by cold adapted species of Pseudomonas, are making their way in food, textiles, and pharmaceuticals. The present review, therefore, aims to summarize the functional versatility of Pseudomonas with particular reference to its peculiarities along with the ecological and biotechnological applications.

The increasing demand for food has increased dependence on chemical fertilizers that promote rapid growth and yield as well as produce toxicity and negatively affect nutritional value. Therefore, researchers are focusing on alternatives that are safe for consumption, non-toxic, cost-effective production process, and high yielding, and that require readily available substrates for mass production. The potential industrial applications of microbial enzymes have grown significantly and are still rising in the 21st century to fulfill the needs of a population that is expanding quickly and to deal with the depletion of natural resources. Due to the high demand for such enzymes, phytases have undergone extensive research to lower the amount of phytate in human food and animal feed. They constitute efficient enzymatic groups that can solubilize phytate and thus provide plants with an enriched environment. Phytases can be extracted from a variety of sources such as plants, animals, and microorganisms. Compared to plant and animal-based phytases, microbial phytases have been identified as competent, stable, and promising bioinoculants. Many reports suggest that microbial phytase can undergo mass production procedures with the use of readily available substrates. Phytases neither involve the use of any toxic chemicals during the extraction nor release any such chemicals; thus, they qualify as bioinoculants and support soil sustainability. In addition, phytase genes are now inserted into new plants/crops to enhance transgenic plants reducing the need for supplemental inorganic phosphates and phosphate accumulation in the environment. The current review covers the significance of phytase in the agriculture system, emphasizing its source, action mechanism, and vast applications.