Prefers aldehydes over alcohols. a primary alcohol + NADP(+) = an aldehyde + H(+) + NADPH Binds 2 Zn(2+) ions per subunit. Has a higher specific activity when grown as a surface pellicle rather than in agitated cultures (at protein level). Not essential for growth, strains missing one copy or both grow slower and have a different morphology than wild-type. Pupylation of this protein has been demonstrated, however it is unknown if the protein concerned is the product of this gene, of the identical gene adhC1 (AC P0CH36), or of both genes. Belongs to the zinc-containing alcohol dehydrogenase family.