Yes, of course, microbes significantly cotribute to digestion process. Even, some carnivorous plants do not produce digestive enzymes and rely only on microbes in digestion process. The pitcher traps are miniature ecosystem with foodweb. They colonise the trap from air or are displaced here by insect prey. See e.g.Koopman MM, Fuselier DM, Hird S, Carstens BC. The carnivorous pale pitcher plant harbors diverse, distinct, and time-dependent bacterial communities.Appl Environ Microbiol. 2010 Mar;76(6):1851-60.