  Recent observations of Type Ia supernova at high redshifts establish that the
dark energy component of the universe has (a probably constant) ratio between
pressure and energy density $w=p/\rho=-1.02(^{+0.13}_{-0.19})$. The
conventional quintessence models for dark energy are restricted to the range
$-1\le w < 0$, with the cosmological constant corresponding to $w=-1$.
Conformally coupled quintessence models are the simplest ones compatible with
the marginally allowed superaccelerated regime ($w<-1$). However, they are
known to be plagued with anisotropic singularities.
  We argue here that the extension of the classical approach to the
semiclassical one, with the inclusion of quantum counterterms necessary to
ensure the renormalization, can eliminate the anisotropic singularities
preserving the isotropic behavior of conformally coupled superquintessence
models. Hence, besides of having other interesting properties, they are
consistent candidates to describe the superaccelerated phases of the universe
compatible with the present experimental data.
