ForestryFermenterAddon is a lightweight mod (~5 KB) which allows to use items from other mods in Fermenter (Forestry mod) to get Biomass. By default config is set for TwilightForest and Thaumcraft 4 mods.

Config example

ModID {
    I:"itemName, meta"=value
    I:"itemName"=value
}

Params:
1. ModID - integrated mod's ID
2. itemName - unlocalized ItemName item
3. meta - integer (see image below, optionally parameter)
4. value - integer, number of Biomass in millibuckets

To get these params install NEI, press F3+H in game and focus cursor on item.

For example:

Thaumcraft {
    I:"blockCustomPlant, 0"=450
    I:"blockCustomPlant, 1"=800
}

Tested on Forestry 3.6, Forge 1.7.10.