Microbial Community Dynamics of Extremophiles/Extreme Environment

Recent Development of Extremophilic Bacteria and Their Application in Biorefinery

“…These inherent characteristics of halophilic and halotolerant microorganisms and the demand for salt tolerance depends on environmental and nutritional factors. They are therefore one of the best choices for biofuel production and other industrial processes (Singh et al, 2019c). It is worth mentioning that the enzymes for biofuel production, such as cellulase, xylanase, laccase etc., from halophilic and halotolerant microorganisms are relatively more stable than those of a terrestrial origin.…”

“…However, most of the earth's crust is covered by extreme environmental conditions in terms of temperatures that can range from −89 • C in the Antarctic/Arctic regions to 400 • C at the deep seafloor (doi: 10.1016/j.biotechadv.2015.11.001). It is thus not surprising that extremophiles have evolved and developed promising strategies and mechanisms to survive best in extreme conditions of pH, temperature, pressure, and other life-supporting conditions (Navanietha Krishnaraj and Sani, 2017;Singh et al, 2019b).…”

“…Extremophilic bacteria could be described as acidophilic (optimally thrive at low pH), alkaliphilic (optimally thrive at high pH), halophilic (thrive well in high concentrations of salt), thermophilic (optimally thrive at high temperature), hyperthermophilic (optimally survive extreme high temperature usually above 80 • C), psychrophilic (thrive well at low temperature), piezophilic/barophilic (optimized growth at high pressure), oligotrophic (grow in nutrient deficient environments), endolithic (grow within rock spaces), and xerophilic (thrives in a dry area). Besides, polyextremophiles and extremotolerant microorganisms are also present in various extreme ecological niches (Dumorné et al, 2017;Gundala and Chinthala, 2017;Singh et al, 2019b). Researchers are interested in understanding their metabolic cycles to utilize them for potential industrial use due to their high stability at elevated temperatures, favoring of the good solubility of substrates, high mass transfer rate, and their lowering of the risk of pollution during industrial processes (Chen and Jiang, 2018).…”

Revisiting the scope and applications of food enzymes from extremophiles

“…These organisms can survive extreme conditions such as high and low temperatures (less than 15ºC and greater than 50°C), acid (pH less than 4), and alkaline (pH greater than 9), high metal concentrations, high radiation and pressures (Dumorne, Córdova, Astorga‐Elo, & Renganathan, 2017; Mirete, Morgante, & González‐Pastor, 2016). Extremophiles can also thrive in environments with little or no nutrients as well as in the presence of extremely high concentrations of heavy metals (Singh, Jain, Desai, Tiwari, & Madamwar, 2019). Several studies have shown that these organisms are good sources of highly active and stable extremophilic enzymes including amylases, lipases, proteases, xylanases, pullulanases, chitinases, pectinases, esterases, isomerases, and dehydrogenases (Agyei et al., 2019; Dumorne et al., 2017; Sarmiento, Peralta, & Blamey, 2015).…”

Diversity of Culturable Halophilic Archaea and Bacteria from Chott Tinsilt and El Malah Salt-Lake in Algeria

“…They may be classified into three main classes according to the quantity of their salt (NaCl) requirements: slight halophiles which require 0.2 to 0.85 M, Moderate halophiles, which require 0.85 to 3.4 M and extreme halphiles, which need 3.4 to 5.1 M of NaCl. Halotolerant microorganisms are those that can grow in the presence and absence of high concentrations of salt (Singh et al, 2019).…”