  Context. Light elements and nitrogen surface abundances together can
constrain the mixing efficiencies in massive stars on the main sequence,
because moderate mixing at the surface leads to a depletion of light elements
but only later to an enrichment in nitrogen. Aims. We want to test the
rotational mixing prescriptions included in the Geneva stellar evolution code
(GENEC) by following the evolution of surface abundances of light isotopes in
massive stars. Methods. The GENEC is a 1D code containing sophisticated
prescriptions for rotational mixing. We implemented an extended reaction
network into this code including the light elements Li, Be and B, which allowed
us to perform calculations testing the rotation induced mixing. Results. We
followed 9, 12 and 15 solar mass models with rotation from the zero age main
sequence up to the end of He burning. The calculations show the expected
behaviour with faster depletion of light isotopes for faster rotating stars and
more massive stars. Conclusions. We find that the mixing prescriptions used in
the present rotating models for massive single stars can account for most of
the observations. However the uncertainties are quite large making it hard to
draw a firm conclusion on the mixing scenario.
