Why is microbial activity slower in cold environments

I know that if the environment is too hot the microbes can die due to denaturing of proteins etc. However, I do not understand why microbes in the cold (such as Pseudomonas) have reduced acvitvity. Why is this?
Thanks

Because all biochemical activity slows down in the cold. Organisms have an optimum operating temperature and as that temperature falls so does the activity.

It is a similar reason, the enzymes are out of their optimal functional temperature range. As the temperature drops the enzymatic reaction rate drops.

Proteins can denature as the cell freezes. As water cools the molecules shift into a different alignment, ice expands so stresses the proteins out of shape normally held by hydrogen bonds.

Specifically, it's because enzymes work more slowly in the cold. In all cases, chemical reactions work faster the higher in temperature you go, and vice versa.

all cells work well only on suitable temperatures