In extreme environments, microbial metabolic processes that lower the energetic cost of maintaining life are favored (Hoehler and Jørgensen, 2013). Such settings are characterized by low growth rates (Lomstein et al., 2012), and most energy is diverted to maintenance functions (van Bodegom, 2007), such as osmotic equilibration, oxygen stress defense, motility, and more sustainable metabolic pathways. These selective conditions for life promote the dominance of prokaryotes and generally favor Archaea relative to Bacteria (Hoehler and Jørgensen, 2013). This is mostly due to the reduced membrane permeability of Archaea, which requires less maintenance energy with respect to bacterial membranes (Valentine, 2007). This advantage is particularly striking in environments characterized by high osmotic stress such as hypersaline environments. There, bacteria may use alternative strategies that allow competition with the putatively better-adapted archaea, for example, by recycling available organic molecules as osmotic solutes (Oren, 1999a). The intracellular accumulation of ambient organic carbon is a common way of economizing energy in harsh environments. For example, under stressed growth conditions, some Bacteria species are known to accumulate intracellular lipid droplets (Alvarez et al., 1997; Wältermann and Steinbüchel, 2005) in the form of polyhydroxyalkanoates, triglycerides, or wax esters (WEs). However, the presence of such mechanisms in the deep biosphere has not yet been documented, suggesting that they may not be sufficiently effective in these low-energy settings for bacteria to survive.