  We examine the effect of boson-fermion interaction in a one-dimensional
Bose-Fermi mixture by using the density matrix renormalization group method. We
show that the boson superfluidity is enhanced by fermions for a weak
boson-fermion coupling at an approximate integer boson filling factor (e.g.,
$0.935\le \rho_b \le 1.0$), and this enhancement is produced both in a fermion
metallic state and in a fermion insulating state. A metal-insulator phase
transition of fermions induced by boson-fermion interaction is observed even
though there is no fermion-fermion interaction in the parent Hamiltonian.
Furthermore, we find that the boson superfluid order and density wave order can
coexist in a deep fermion Mott region. All these features could be measured in
future experiments and open up the possibility of detecting the new physical
effect in the Bose-Fermi mixture.
