Cellulose paste is used in the production chains for modules and alien science.
These production chains may be relying on the presence of some of Bob's mods: I believe you will need Bob's modules, Bob's enemies, and Bob's Tech for these production chains to be available.
Furthermore, there were changes to these production chains in the recent months.
Which versions of Factorio, and which of Angel's and Bob's mods do you use?
By the way: some helper mods like "FNEI", "What is it really used for", or "Helmod" are very convenient to figure out how specific production chains work.