undigested residue造句

The undigested residue from the fermentation may be used in gasification to make hydrogen ( H 2 ).
Exocytosis occurs in various cells to remove undigested residues of substances brought in by endocytosis, to secrete substances such as hormones and enzymes, and to transport a substance completely across a cellular barrier.
If then, the undigested residue ( mostly lignin ) is used to produce hydrogen by gasification, it is ensured that more energy from the biomass will end up as liquid fuels rather than excess heat / electricity.
It's difficult to find undigested residue in a sentence. 用undigested residue造句挺难的