Or search: boil, sour, wake, ignite, seethe, unrest, convert, ferment, inflame, zymosis, upheaval, agitation, zymolysis, fermenting, turbulence
2 Syllables: SU
Bennett, ended, lengthened, Lennox, Lenox, mentioned, rented, Senate, strengthened, temperate, template, tempted, tended, tenet
3 Syllables: USU
ascended, attempted, attended, augmented, contented, defended, depended, descended, extended, intentioned, invented, offended, presented, pretended, relented, resented, suspended
4 Syllables: UUSU
apprehended, recommended, represented

Found 34 words across 3 groupings. Skipped 1 excess word of a similar stem.