21 February 2024
  • Share

Biological material, which the EPO understands to be any material containing genetic information and capable of reproducing itself or being reproduced in a biological system (Rule 26(3) EPC), is patentable in all major jurisdictions around the world. Inventions relating to biological material have to fulfil the same patentability requirements as inventions in all other fields of technology, one of which is that the application or patent “sufficiently discloses the invention so that it can be carried out by a person skilled in the art”. However, it is not always possible to describe biological material for which protection is sought in such a way that the EPO will acknowledge that the invention is sufficiently disclosed. This is particularly true for microorganisms, which are the focus of a growing number of biotechnology patent applications (see our related article on microbiome-related patents here).

In such cases and where the biological material is not publicly available, an applicant can deposit the biological material at an International Depository Authority (IDA) recognized by the patent office of the country in which protection is sought and refer to that deposit in the patent application. To avoid repeating this process in every jurisdiction in which protection is sought, the signatories of the 1977 Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Protection (the “Budapest Treaty”) agreed to recognize deposits of biological material at a number of IDAs in different jurisdictions. From the point at which the treaty entered into force in 1980, an applicant can validly refer to a single deposit at one of the recognized IDAs when pursuing patent protection in any of the jurisdictions party to the Budapest Treaty. A full list of the recognized IDAs can be found here.

Depositing samples

One of the pitfalls in using deposits to provide sufficient disclosure is that many jurisdictions party to the Budapest Treaty, including Japan, Korea and all EPO member states, require the relevant biological material to be deposited by the time of filing of the application (or priority application, where relevant) at the latest (see, for example, Rule 31(a) EPC)[1]. Where a deposit has only been made after the filing/priority date and sufficiency of disclosure of claimed subject-matter is dependent on the deposit, the original filing/priority date of the claimed subject-matter is lost and the subject matter has to be pursued in a separate application. One notable exception is the USA, where (under the law of ‘enablement’) a deposit must be made no later than within the time period set in the Notice of Allowance[2].

Therefore, the process for submitting a sample to an IDA ideally should be started several months before filing of the application. Depending on the IDA different forms will have to be sent together with the sample to be deposited. It is important to also include instructions on culturing the sample, because the relevant IDA will carry out a viability test. When the sample is received, most IDAs issue an informal receipt with a deposit date and provisional accession number. At this stage, the applicant could already file the patent application (containing details of the sample type, depositary institution, date, and any provisional accession number) and submit the formal receipt and accession number at a later date, e.g. at the EPO or IB within 16 months of the filing or priority date[3]. However, if the IDA finds the deposited biological material not to be viable, a replacement sample has to be provided and the date of deposit of the original sample is lost. It is therefore advisable to receive the issuance of a confirmation of viability and the accession number before the filing date.

But even in cases where an application needs to be drafted and filed at short notice (so a delay of several months to filing is not available), the finding of an unviable sample is still not fatal. So long as the application has not published before the submission of a replacement sample, you can file a further application that refers to the replacement deposit. If the earlier application has not published by the time the later application is filed, the earlier application would not count as prior art in Japan or Korea, while in Europe and the UK, depending on where the application was filed, the earlier application would at most count as prior art for the purposes of novelty only. The filing of a second application may therefore rescue a situation in which a deposited sample has been found not to be viable. (In the US, this rescue strategy will probably be unnecessary because, as noted above, a viable deposit is only required by the (later) three month period triggered by the Notice of Allowance.)

Deposits made by a person other than the applicant

Can patent applicants refer to a biological deposit to support and sufficiently disclose their invention, even if they were not the depositor? Yes, but additional requirements and limitations may apply. For instance, the EPO requires the name and address of the depositor to be stated in the patent application. Moreover, evidence that the depositor “has authorised the applicant to refer to the deposited biological material in the application and has given his unreserved and irrevocable consent to the deposited material being made available to the public” must be submitted within 16 months of the filing or priority date, or before completion of the technical preparations for publication of the EP application (Rule 31(1)(d) EPC).

Third party access to deposits

Besides the submission process, another crucial aspect to consider is the duration for which deposited samples are kept at IDAs and the accessibility of the deposited samples to third parties. Under the Budapest Treaty, IDAs are required to retain samples for at least the later of 30 years from the date of deposit of the biological material or 5 years from the most recent request for furnishing a sample[4]. During this time, Rule 11.3 of the Budapest Treaty requires the relevant IDAs to furnish a sample to any authority, natural person or legal entity upon request – with the only limitation under Rule 11.3(iii) being that the authority, natural person or legal entity has the right to a sample under the patent law governing the patent/application that refers to the sample. In the case of a PCT application, this means the patent law governing procedure before the “designated office” (see Rule 11.5 of the Budapest Treaty).

If the application has been filed before the EPO, access of third parties to the deposit can be restricted by choosing the so-called “expert solution”. (This restriction is only available if the applicant has made the deposit themselves; see Rule 31(1)(d) EPC, above. To apply this restriction, applicants must inform the EPO before preparations for publication of the application have concluded – usually at least 5 weeks before the publication date at the 18-months mark from the filing date.) This allows the applicant to limit issuance of a sample by an IDA to a nominated expert (on the condition that the expert is independent[5]) until the grant of the European patent or, if the application is refused or withdrawn, the period of 20 years from filing of the application. However, this still leaves the period after grant when competitors can request samples themselves, albeit only for experimental purposes and on the condition that the biological material is not made available to any third party[6]. This availability post-grant might not cause undue concern if the biological material is covered by the granted claims, but may be undesirable if the granted claims do not effectively cover the biological material.

Similar rules for limiting third party access to deposited samples apply in the US, where access to the biological material is restricted for pending or abandoned applications but any substantive restrictions imposed by a depositor are irrevocably removed upon grant of the patent[7]. In Japan, access to a deposited sample to third parties is also limited to exceptional circumstances until grant of the patent[8].

Given the above requirements for IDAs to furnish and retain deposits, it is critical to carefully consider, whether a deposit is essential or there are other ways to ‘sufficiently disclose’ the invention without allowing your competitors access to valuable microbes in the future. This should be considered when preparing your patent application and deciding your filing strategy. Moreover, if you intend to use the EPO’s “expert solution” (and equivalent provisions elsewhere), you should check that such provisions are available at each IP office at which the application is to be filed[9].


One increasingly popular option in the microbiome field is to protect consortia, i.e. groups of different bacteria co-operating with each to achieve a certain effect. IP considerations around consortia in general have been summarized in this article. Since they contain more than one bacterial strain, specific considerations apply for depositing microbial consortia. While many IDAs accept bacterial strains and publish instructions for the process of depositing them, this is not the case for consortia. IDAs which currently do not accept consortia include those in major EPO member states such as the NCIMB in Aberdeen (one of three IDAs for bacteria in the UK), the CNCM at the Institut Pasteur in Paris (the only IDA in France) and the CBS in Utrecht (the only IDA in the Netherlands).

IDAs among EPO member states that do accept microbial consortia include CABI in Egham, UK, DSMZ in Braunschweig, Germany and KPD in Gdansk, Poland.

KPD requires that the different strains in a consortia can be distinguished, the viability of each strain can be tested individually and the mixture can be preserved without losing one of the strains. While no upper limit is provided on how many strains can be included in a consortium, such deposit requirements may constitute a limiting factor. Similar requirements apply for DSMZ but consortia are limited to two different microbial strains. CABI accept consortia provided that the requirements of Rule 6.1(iii) of the Budapest Treaty are fulfilled. For consortia, these specifically encompass providing “descriptions of the components of the mixture and at least one of the methods of permitting the checking of their presence”.

In the US, ATCC in Manassas accepts consortia. NITE Patent Microorganisms Depositary (NPMD) in Tokyo, Japan, also accept consortia of several microorganisms on the condition that it must be possible to detect the presence of all the microorganisms contained in a consortium with a method supported by NPMD (this includes PCR amplification, morphological observation and colony formation). One method specifically excluded is amplicon sequencing analysis by next-generation sequencing methods.

In Korea, the Korean Collection for Type Cultures (KCTC) accepts consortia of up to eight strains, but not those that are only identifiable by next generation sequencing. They also require the constituent strains of the consortium to be deposited separately, as isolated strains.


When considering applying for patent protection of microbes worldwide, one important consideration is how to ‘sufficiently disclose’ the claimed subject-matter (a similar concept to ‘enablement’ in the USA). If sufficient disclosure / enablement might rely on depositing a microbial strain or a consortium, care should be taken to (a) be aware of the specific requirements of the IDA of choice (e.g. number of vials of each strain), (b) start the process of preparing and submitting samples for deposit to the IDA as early as possible (e.g., to mitigate the risk that the deposited sample is found non-viable and must be resubmitted), and (c) fully research the available restrictions for third party access to the deposited strains in the jurisdictions covered by the patent application.


This blog was updated 3 April 2024.



  1. For Japan, see the section on Japan of WIPO’s Guide to the Deposit of Microorganisms under the Budapest Treaty linked here, which refers to Regulations under the Patent Law, Rule 27bis, and Examination Handbook for Patent and Utility Model in Japan, Annex B, Chapter 2, 1.1.4 Deposit and Furnishing of Biological Material, Part a
  2. See 37 CFR 1.804 Time of making an original deposit
  3. See Rule 31(2)(a) EPC and Rule 13bis.4 PCT
  4. See Rule 9.1 of the Budapest Treaty
  5. The expert has to sign a declaration to that end. Decision of the President of the European Patent Office dated 10 July 2017 concerning the requirements and obligations for experts nominated under Rule 32 EPC.
  6. See Rule 33(2) EPC
  7. See 37 CFR 1.808 Furnishing of samples
  8. See Examination Handbook for Patent and Utility Model in Japan, Annex B, Chapter 2, 1.1.4 Deposit and Furnishing of Biological Material, Part b
  9. Section E of the Guide to the Deposit of Microorganisms under the Budapest Treaty sets out the requirements of the IPOs of each signatory state.

About the authors

This blog was co-authored by Florian Zobel and Eliot Ward.

Florian Zobel author image



Florian Zobel

Florian is a trainee patent attorney and part of our life sciences team. His background is in the field of molecular biology, particularly in the context of the human DNA damage response. Florian has a PhD in Molecular Cell Biology in Health and Disease from the University of Oxford. The focus of his work has been the study of ADP-ribosylation in human DNA damage repair. He has published in notable journals on the subject, particularly regarding the molecular basis of serine ADP-ribosylation and its significance for the cellular toleration of PARP inhibitors, a group of small molecule inhibitors used in the treatment of breast, ovarian and other cancers.

Email: florian.zobel@mewburn.com

Eliot handles a diverse client portfolio spanning the life sciences sector and a growing practice in the cross-over space between physics and biology. A skilled patent prosecutor, Eliot also has wide experience of drafting patent applications on breakthrough technologies, as well as leading offensive and defensive opposition proceedings post-grant. Eliot is also experienced in handling Freedom to Operate projects and in performing due diligence, which have led to the successful completion of high value transactions and investment rounds.

Sign up to our newsletter: Forward - news, insights and features

Our People

Our IP specialists work at all stage of the IP life cycle and provide strategic advice about patent, trade mark and registered designs, as well as any IP-related disputes and legal and commercial requirements.


Contact Us

We have an easily-accessible office in central London, as well as a number of regional offices throughout the UK and an office in Munich, Germany.  We’d love to hear from you, so please get in touch.