Psychrotrophic Bacteria
It is not necessarily about special (psychrophilic) genes, but rather about psychrophilic variants of their mesophilic and thermophilic homologs.

In general, lower temperature means lower rate of enzymatic reactions. 

To cope with this problem, psychrophilic bacteria encode enzymes with highly mobile surface loops (higher mobility, higher catalytic rate).

Thermophilic bacteria have a different problem: enzymatic reactions are fast, but the enzymes are unstable; to cope with this problem, thermophilic bacteria encode enzymes with more rigid surface loops (more rigid, more stable).

Sočan et al. (2018) Catalytic Adaptation of Psychrophilic Elastase. Biochemistry 57: 2984-2993.
Åqvist (2017) Cold Adaptation of Triosephosphate Isomerase. Biochemistry 56: 4169-4176.