The word penicillinases is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 24
Highest Scoring Words With Friends™ Plays In The Letters penicillinases
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Seven Letter Word Alert: (66 words)
alpeens, alpines, aniline, asinine, canines, capless, caseins, cleanse, eclipse, elapses, ellipse, encases, enclasp, enseals, escapes, iceless, icepail, iciness, illness, incense, incises, inclasp, incline, inlines, inplace, inscape, laicise, liaises, license, lipases, lipless, napless, niacins, palsies, panicle, pansies, pelican, penance, pencase, pencils, penises, pennies, pieless, pinenes, pinless, pleases, salines, scalene, scalpel, scillas, seances, siennas, silanes, silence, silicas, silicle, spaniel, special, species, spelean, spinals, spinels, spleens, splenic, splices, splines