Psychrophilic organisms possess several adaptive strategies which allow them to sustain life at low temperatures between −20 to 20 °C. Studies on Antarctic psychrophiles are interesting due to the multiple stressors that exist on the permanently cold continent. These organisms produce, among other peculiarities, cold-active enzymes which not only have tremendous biotechnological potential but are valuable models for fundamental research into protein structure and function. Recent innovations in omics technologies such as genomics, transcriptomics, proteomics and metabolomics have contributed a remarkable perspective of the molecular basis underpinning the mechanisms of cold adaptation. This review critically discusses similar and different strategies of cold adaptation in the obligate psychrophilic yeast, Glaciozyma antarctica PI12 at the molecular (genome structure, proteins and enzymes, gene expression) and physiological (antifreeze proteins, membrane fluidity, stress-related proteins) levels. Our extensive studies on G. antarctica have revealed significant insights towards the innate capacity of- and the adaptation strategies employed by this psychrophilic yeast for life in the persistent cold. Furthermore, several cold-active enzymes and proteins with biotechnological potential are also discussed.

Extremely low temperatures present various challenges to life that include ice formation and effects on metabolic capacity. Psyhcrophilic microorganisms typically have an array of mechanisms to enable survival in cold temperatures. In this study, we sequenced and analysed the genome of a psychrophilic yeast isolated in the Antarctic region, Glaciozyma antarctica. The genome annotation identified 7857 protein coding sequences. From the genome sequence analysis we were able to identify genes that encoded for proteins known to be associated with cold survival, in addition to annotating genes that are unique to G. antarctica. For genes that are known to be involved in cold adaptation such as anti-freeze proteins (AFPs), our gene expression analysis revealed that they were differentially transcribed over time and in response to different temperatures. This indicated the presence of an array of adaptation systems that can respond to a changing but persistent cold environment. We were also able to validate the activity of all the AFPs annotated where the recombinant AFPs demonstrated anti-freeze capacity. This work is an important foundation for further collective exploration into psychrophilic microbiology where among other potential, the genes unique to this species may represent a pool of novel mechanisms for cold survival.