Survival strategies of microorganisms in low-energy environments

Abstract:

Microorganisms have survived and evolved in continuously changing and energy-limited environments for billions of years. Compared with those cultured in laboratories with abundant organic substrates, the microorganisms in natural oligotrophic environments exhibit significant differences in physiological states, gene expression, and protein synthesis. Under extreme and low-energy environmental stress, microorganisms utilize a range of substances such as hydrogen, ferrous ions, minerals, and organic remnants as energy or electron sources. They adjust their gene expression, metabolic pathways, and physiological states through various mechanisms to enhance energy utilization efficiency, adapt to nutrient-scarce conditions, sustain metabolic activities and population survival, and drive material transformation and element cycling. Understanding the physiological states of microorganisms in natural environments and their adaptive mechanisms to low-energy supply is crucial for revealing the microbial origins, evolution, growth, metabolism, dormancy, and the minimum energy requirements for life. This review introduces the formation, evolution, and distribution of natural low-energy environments (i.e., environments deficient in electron donors and carbon sources), as well as the physiological states and survival strategies of microorganisms in these variable low-energy environments. The research in this field advances microbial remediation technology development, extreme environment protection, and bio-mining technology development, representing a frontier in geomicrobiology.