Noncommutative symmetric functions IV: Quantum linear groups and hecke algebras at q = 0

We present representation theoretical interpretations of quasi-symmetric functions and noncommutative symmetric functions in terms of quantum linear groups and Hecke algebras at q = 0. We obtain in this way a noncommutative realization of quasi-symmetric functions analogous to the plactic symmetric functions of Lascoux and Schutzenberger. The generic case leads to a notion of quantum Schur function.