Some people are searching for cryophilic cellulases and proteases:

http://en.cnki.com.cn/Article_en/CJFDTOTAL-WSWX200903025.htm

http://link.springer.com/article/10.1023/A:1016383212244

http://link.springer.com/article/10.1007/s12010-012-9582-2

http://en.cnki.com.cn/Article_en/CJFDTOTAL-HYKX200305010.htm

http://link.springer.com/chapter/10.1007/978-3-642-53971-8_14

If you have a particular process in mind, then the answer could be more specific. ;)

Most of the enzymes work at 25 to 30 degree temperature. I dont see a need for enzymes working at zero degree. As also the reaction rates increase with temperature. World is looking at enzymes working at higher temperatures. If your concern is about work in the low temperature regions, then probably a detailed study of microbes isolated from these regions will provide better answer. Also other parameters like solubility of reactatnts, products at such low temperatures pose restrictions on or no benefits of zero degree optimum.

Allow me to disagree with the previous answer. There are many fields where enzymes working at low to very low temperatures may be important and information about their properties and availability is precious. Using cold temperature looks a very effective way to selectively get an enzymatic reaction done while all the other enzymes will not work, with no need to add enzyme inhibitors or so on.

Just think of those processes where you want to treat a certain matrix but you want to keep it refrigerated to avoid degradation (such as fish, meat, vegetables, other foods, but also in several laboratory applications) or where you have to treat items or surfaces on a large scale or "in the field" and you cannot set the temperature at your convenience.

That is why I would thank Bernardo Duarte for his question and Christoph Kulmann for his answer.

To list such enzymes here is impossible due to insufficient space. You may carry out searches using databases like SwissProt.