The 3-COL problem consists on deciding if the regions of a map can be
coloured with only three colors bearing in mind that two adjacent regions must be
coloured with di erent colors. It is a NP problem and it has been previously used in
complexity studies in membrane computing to check the ability of a model for solving
problems of such complexity class. Recently, tissue P systems with proteins on cells have
been presented and its ability to solve NP-problems has been proved, but it remained
as an open question to know if such model was still able to solve such problems if the
environment was removed. In this paper we provide an a rmative answer to this question
by showing a uniform family of tissue P systems without environment and with proteins
on cells which solves the 3-COL problem in linear time
