  We present ALMA data on the 3mm continuum emission, CO isotopologues (12CO,
13CO, C18O), and high-density molecular tracers (HCN, HCO+, HNC, HNCO, CS, CN,
and CH3OH) in NGC4526. These data enable a detailed study of the physical
properties of the molecular gas in a longtime resident of the Virgo Cluster;
comparisons to more commonly-studied spiral galaxies offer intriguing hints
into the processing of molecular gas in the cluster environment. Many molecular
line ratios in NGC4526, along with our inferred abundances and CO/H2 conversion
factors, are similar to those found in nearby spirals. One striking exception
is the very low observed 12CO/13CO(1-0) line ratio, $3.4\pm0.3$, which is
unusually low for spirals though not for Virgo Cluster early-type galaxies. We
carry out radiative transfer modeling of the CO isotopologues with some
archival (2-1) data, and we use Bayesian analysis with Markov chain Monte Carlo
techniques to infer the physical properties of the CO-emitting gas. We find
surprisingly low [12CO/13CO] abundance ratios of $7.8^{+2.7}_{-1.5}$ and
$6.5^{+3.0}_{-1.3}$ at radii of 0.4 kpc and 1 kpc. The emission from the
high-density tracers HCN, HCO+, HNC, CS and CN is also relatively bright, and
CN is unusually optically thick in the inner parts of NGC4526. These features
hint that processing in the cluster environment may have removed much of the
galaxy's relatively diffuse, optically thinner molecular gas along with its
atomic gas. Angular momentum transfer to the surrounding intracluster medium
may also have caused contraction of the disk, magnifying radial gradients such
as we find in [13CO/C18O]. More detailed chemical evolution modeling would be
interesting in order to explore whether the unusual [12CO/13CO] abundance ratio
is entirely an environmental effect or whether it also reflects the relatively
old stellar population in this early-type galaxy.
