R. 26(6) EPC defines a "microbiological process" as any process involving or performed upon or resulting in microbiological material. The boards have not yet issued a decision interpreting this definition.

According to T 356/93 (OJ 1995, 545), the concept of "microbiological processes" under Art. 53(b) EPC, second part of sentence, EPC refers to processes in which micro-organisms (or their parts) are used to make or to modify products or in which new micro-organisms are developed for specific uses. Consequently, the concept of "products thereof" under Art. 53(b) EPC, second part of sentence, EPC encompasses products which are made or modified by micro-organisms as well as new micro-organisms as such. The board defined the term "micro-organism" as including not only bacteria and yeasts, but also fungi, algae, protozoa and human, animal and plant cells, i.e. all generally unicellular organisms with dimensions not visible to the naked eye which can be propagated and manipulated in a laboratory, including plasmids and viruses.

Examining the patentability of the claimed plant grouping, the board in T 356/93 also addressed the issue whether multi-step processes for producing plants which include at least one microbiological process step could be considered as a whole to represent "microbiological processes", and whether, consequently, the products of such processes (e.g. plants) might be regarded as being "the products thereof" for the purposes of this provision. The board held that "technical processes including a microbiological step" could not simply be equated with "microbiological processes". Nor could the resulting final products of such a process (e.g. plant varieties) be defined as "products of a microbiological process" within the meaning of the said provision.