Infinitives can also be substantivated without any preposition, just add an article and the noun is done. The same principle is possible with many English verbs with the principle article + verb + ing.
Examples
Das Züchten von genmanipuliertem
Mais wird kontrovers diskutiert.
= The growing of gen-manipulated mais is discussed controversially.
Das Aufeinanderprallen zweier Kulturen ist bei vorhandener Intelligenz
ein bereichernder Prozess.
= Assuming a certain intelligence the meeting of two cultures is an enriching process.
