Cold-adapted organisms face several challenges at low temperatures, including reduced reaction rates. To cope, psychrophiles have developed molecular adaptations including modifying membrane fatty acid composition to maintain fluidity, producing antifreeze proteins, and sensing environmental temperature. Genome analyses have provided insights into these adaptations, showing genes for transporters, enzymes, cryoprotectants, and more. Psychrophilic enzymes have high activity at cold temperatures and potential applications. Overall, synergistic changes across genomes allow psychrophilic lifestyles through increased plasticity and specialized proteins, membranes, and pathways.

1. Molecular adaptations in psychrophiles: insights from “omic’’ methods

5. Physiological adaptations of psychrophiles

10. Mechanism for coupling of transcription and translation through CSPs and CSHs . Crystal structure of CspB from Bacillus subtilis in complex with ssDNA Fluorescence microscopy of Bacillus subtilis cells (Walid, M.E .et al . 2006)

11. Schematic view of the pattern of protein expression after cold shock. Schematic representation of the Csp function during acclimation phase . (Horn,G. etal .2007)

19. (Baermans C. et al 2007) Molecular adaptation Explanation Genes involved Membranes Increase the fluidity of cellular membranes Desaturases Freeze-protection Reduction of freezing point of cytoplasm Antifreeze proteins and ice-binding proteins Cold-shock and acclimation response Cellular response to lowering of temperature RNA-binding protein Protection against reactive oxygen species (ROS) Increased solubility of oxygen at low temperature Catalases, peroxidases Proteins and enzymes Maintain catalytic efficiency at low temperatures Reduced proline, internal hydrophobicity Genome plasticity To increase the adaptation ability to cope with low temperatures Transposases, prophages Molecular adaptations in cold adapted bacteria

25. Cavicchioli R . et al 2002 Microorganism or product Application Polyunsaturated fatty acids Dietary supplements for humans, livestock and fish Ice nucleation proteins Food industry, synthetic snow Antifreeze proteins and solutes Cryoprotectants, cold-active catalysts Cold-adapted bacteria and fungi Food industry, including cheese and yoghurt manufacture, meat tenderising, flavour modification and lactose removal from milk Cold-adapted bacteria and fungi Bioremediation of ocean oil spills, contaminated ground water and toxic waste Ice – bacteria Frost protection for plants Methanogenic Archaea Methane production, low temperature waste treatment Examples of applications (other than enzymes) of cold-adapted microorganisms and their products