The document discusses the regulatory landscape for genetically modified (GM) yeast strains used in distillers co-products, primarily focusing on their role in enhancing ethanol production from fuel sources. It outlines the various approval pathways and requirements set by agencies like the FDA and EPA, highlighting the challenges and limited success in obtaining Generally Recognized as Safe (GRAS) status for these yeast strains. The author advocates for a streamlined approval process, arguing that comparison of modified strains to their wild-type counterparts should suffice for safety assessments given the long history of their use.

1. Simplifying Regulatory Approvals
for Genetically Modified Yeast in
Distillers Co-Products
David J. Glass, Ph.D.
D. Glass Associates, Inc.
Fuel Ethanol Workshop
June 21, 2016

2. ∗ Over 43 million tons of DDGS produced in the U.S. in
2013-2014 (approx. 33 million used domestically, 10
million exported)1.
∗ Approximately 98% of the distillers grains used in North
America are a byproduct of fuel ethanol production2.
1. Source: Iowa State University. http://www.extension.iastate.edu/agdm/crops/outlook/dgsbalancesheet.pdf
2. Source: University of Minnesota, Distillers Grains By-products in Livestock and Poultry Feeds, 2007 , cited on FDA
website, http://www.fda.gov/AnimalVeterinary/Products/AnimalFoodFeeds/Contaminants/ucm190907.htm
Distillers Co-Products

3. Use of Modified Yeast Strains in
Distillers Co-Products
∗ Growth in the U.S. ethanol industry has
Increased interest in the development
of modified yeast strains to improve
ethanol production.
∗ This has led to increased interest in the
use of modified yeast strains in
distillers co-products.

4. Researchers are modifying S. cerevisiae in several ways
to improve ethanol production:
∗ Express enzymes to improve feedstock processing.
∗ Impart new pathways to utilize C5 sugars,
e.g. from cellulosic feedstocks.
∗ Metabolic engineering to reduce byproducts
like glycerol.
∗ Improve ethanol tolerance of strains.
Modified Yeast Strains to Improve
Ethanol Production

5. ∗ Industrial use of modified yeast strains is regulated
by EPA under its TSCA biotechnology rules.
∗ Although some uses are exempt, there have been at
least 27 Microbial Commercial Activity Notices
reviewed and cleared by EPA for different modified S.
cerevisiae strains1.
∗ Use of GMO Yeast in DDGs regulated as Animal Feed
Ingredients.
1. Source: https://www.epa.gov/regulation-biotechnology-under-tsca-and-fifra/tsca-biotechnology-notifications-status
Regulation of Industrial Use of
Modified Yeast Strains

6. ∗ FDA regulates food and feed.
∗ Manufacturers must not introduce foods that are
adulterated.
∗ Ingredients that have not been used in food are
considered “additives” and must be
reviewed for safety and efficacy.
∗ Certain products, like traditional DDGs,
considered GRAS due to long history of use;
others can achieve GRAS status as well.
U.S. Regulation of Animal Feed
Ingredients

7. FDA Biotechnology policy is not clear on the extent of genetic
changes to an organism that would trigger need for new review.
FDA Genetic Engineering Policy
Comments questioned whether a substance (including microbes)
that is GRAS could lose its GRAS status solely because it was
produced or modified by new biotechnology. The answer is yes, if
the substance (and its contaminants) has been altered in such a way
that it can no longer be generally recognized by qualified experts to
be safe. In this instance, the substance would be a food additive.
Source: FDA Statement in Coordinated Framework for Biotechnology Regulation, 1986

8. Although overseen by FDA CVM there are several
options for approval of new feed ingredient:
∗ GRAS Self-determination
∗ GRAS Self-determination, notification to FDA
∗ FDA Feed Additive Petition
∗ AAFCO New Ingredient Definition
U.S. Regulation of Animal Feed
Ingredients

9. Different Paths to Approval
∗ The different pathways all generally require the same
types of data.

10. ∗ Manufacturing Chemistry; Analytical Methods
∗ Identity
∗ Manufacturing process and controls
∗ Product specifications
∗ Stability (product and in feed)
∗ Analytical methods: product, quantification in feed
∗ Utility
∗ Intended Use
∗ Feeding studies to show efficacy?
∗ Safety
∗ Target Animal – white paper or studies
∗ Human food -- Toxicology and Residue Chemistry – white paper or studies
∗ Environmental – Assessment or Categorical Exclusion
Adapted from K. Smedley presentation at 2016 AAFCO Midyear Meeting, January 2016
Data Requirements for FDA, AAFCO
Approval Pathways

11. Different Paths to Approval
∗ The different pathways all generally require the same
types of data.
∗ The same group at FDA CVM conducts the technical
review under all the pathways.
∗ There are pros and cons to each approach, but –
∗ The track record to date for approvals of modified
yeast strains has been very limited.

12. ∗ Under U.S. law, a product for use in food or feed can be
determined to have GRAS status in two ways:
∗ Experience based on common use in food or feed or
∗ “Scientific principles” – that, based on publicly available
information, there is a consensus among qualified experts
that those data and information establish that the substance
is safe under the conditions of its intended use
∗ A manufacturer can make such determinations itself, usually
based on the advice of an expert scientific panel.
GRAS Self-Determination

13. ∗ Established 2010, modeled after
successful program for GRAS substances
in human food.
∗ Applicant makes its own GRAS
determination, submits dossier to obtain
FDA concurrence.
∗ FDA responds either “no questions” or
“does not support GRAS status”.
∗ To date, 20 submissions, only 7 of which
received favorable “FDA has no
questions” ruling.
FDA CVM GRAS Notification Program

14. GRAS Notification Process: No
Successful Yeast Strain Requests
Submitter Product Purpose Status
Gevo Inactivated
modified S.
cerevisiae
Component of animal feed when
used in the fermentation and
distillation of corn to produce
isobutanol
Notice does not provide a
basis for a GRAS
determination
Gevo Isobutanol distillers
grain
Component of animal feed At notifier's request, FDA
ceased to evaluate the
notice
DSM Inactivated
modified S.
cerevisiae
Component of animal feed when
used in the fermentation of corn
to produce ethanol
At notifier's request, FDA
ceased to evaluate the
notice (Resubmitted
4/29/16, pending)
http://www.fda.gov/AnimalVeterinary/Products/AnimalFoodFeeds/GenerallyRecognizedasSafeGRASNotifications/ucm243845.htm

15. ∗ AAFCO established a process to
add approved new ingredient
definitions to their Official
Publication.
∗ Applicants submit dossier to
AAFCO Investigator, for review by
FDA CVM.
∗ New definitions approved by
Ingredient Definition Committee
and full AAFCO membership.
AAFCO New Ingredient Definition
Process
AAFCO: Association of American
Feed Control Officials

16. Successful AAFCO Requests for
Novel Yeast Strains
Source: 2016 AAFCO Official Publication, pp. 443-444.

17. AAFCO Process is manageable but time-consuming
12-18 mos 3-6 mos 6 mos 12 mos minimum
Submission
CVM Review
CVM
Letter
AAFCO
Ingredients
Definition
Cmte Vote
Good case scenario: 36 months from submission to publication
Biannual meeting cycle Annual publication cycle
CVM & AAFCO MOU: The 2 organizations work together under a
Memorandum of Understanding that currently expires Sept 2017
Publication in the
“next” Official
Publication
AAFCO General
Membership
Vote
Slide courtesy of Kevin Wenger, Mascoma/Lallemand, used with permission

18. Pros Cons
GRAS Self-determination Does not require agency
review
Not recognized by many
states, Canada
GRAS Notification through
FDA
When successful, GRAS
status clearly established
Program has not worked
well, especially for biotech
products
Feed Additive Petition
through FDA
If approved, legal status
clear at FDA and AAFCO
Time-consuming, requires
rule-making, no precedent
for yeast
AAFCO Ingredient
Definition
Iterative review process,
approval clears marketing
in all states
Time-consuming,
dependent upon AAFCO
meeting schedule
Different Paths to Approval

19. ∗ For modifications to microorganisms with a long
history of use in food and feed, including
Saccharomyces cerevisiae yeast, why should animal
feeding studies be needed to show safety?
∗ Shouldn’t comparison to naturally-occurring species
(or ingredient containing naturally-occurring
organism) be sufficient?
∗ A better model is the Voluntary Consultation program
in place since 1996 for GMO crop plants.
Use in Feed of Yeast and other
Familiar Microorganisms

20. ∗ Limited to plant species:
microorganisms excluded by definition.
∗ Process:
∗ Initial consultations.
∗ Submission of company’s safety
and nutritional assessment.
∗ Review by Biotechnology Evaluation
Team with members from FDA CFSAN
and CVM.
∗ FDA may request a meeting, or
submission of more data.
FDA Voluntary Consultation for GMO
Crops

21. ∗ FDA may conclude:
∗ No further questions
∗ The product requires review as
a food additive
∗ There are other regulatory issues
(e.g. labeling requirements) to be
addressed.
∗ Consent given to > 170 cases to date.
∗ Average time to decision has been
increasing over time, but is approximately 20-24 months.
FDA Voluntary Consultation for GMO
Crops

22. Adapting the Voluntary Consultation
Process for Microorganisms (1)
FDA Voluntary Consultation Program Proposed New Process
The name of the bioengineered food and the crop from which it
is derived.
The name of the modified feed ingredient and the microbial
species from which it is derived, including documentation of
taxonomy.
A description of the various applications or uses of the
bioengineered food, including animal feed uses.
A description of the applications or uses of the modified feed
ingredient in animal feed, including any use limitations, and the
identity of the target animal species. Identification of current or
prior uses of the selected microbial species in animal feed, to
which the proposed use(s) can be compared.
Information concerning the sources, identities, and functions of
introduced genetic material.
Information concerning the sources, identities, and functions of
introduced genetic material.
Information on the purpose or intended technical effect of the
modification, and its expected effect on the composition or
characteristic properties of the food or feed.
Information on the purpose or intended technical effect of the
modification, and its expected effect on the composition or
characteristic properties of the modified feed ingredient derived
from the modified microorganism.

23. Adapting the Voluntary Consultation
Process for Microorganisms (1)
FDA Voluntary Consultation Program Proposed New Process
The name of the bioengineered food and the crop from which it
is derived.
The name of the modified feed ingredient and the microbial
species from which it is derived, including documentation of
taxonomy.
A description of the various applications or uses of the
bioengineered food, including animal feed uses.
A description of the applications or uses of the modified feed
ingredient in animal feed, including any use limitations, and the
identity of the target animal species. Identification of current or
prior uses of the selected microbial species in animal feed, to
which the proposed use(s) can be compared.
Information concerning the sources, identities, and functions of
introduced genetic material.
Information concerning the sources, identities, and functions of
introduced genetic material.
Information on the purpose or intended technical effect of the
modification, and its expected effect on the composition or
characteristic properties of the food or feed.
Information on the purpose or intended technical effect of the
modification, and its expected effect on the composition or
characteristic properties of the modified feed ingredient derived
from the modified microorganism.

24. Adapting the Voluntary Consultation
Process for Microorganisms (2)
FDA Voluntary Consultation Program Proposed New Process
Information concerning the identity and function of expression
products encoded by the introduced genetic material, including
an estimate of the concentration of any expression product in
the bioengineered crop or food derived thereof.
Information concerning the identity and function of expression
products encoded by the introduced genetic material, including
an estimate of the concentration of any expression product in
the modified feed ingredient.
General description of the manufacturing process of the
modified feed ingredients.
Information regarding any known or suspected allergenicity and
toxicity of expression products and the basis for concluding that
foods containing the expression products can be safely
consumed.
Information regarding any known or suspected allergenicity**,
pathogenicity or toxicity of expression products and the basis
for concluding that modified feed ingredients containing the
expression products can be safely consumed.
Information comparing the composition or characteristics of the
bioengineered food to that of food derived from the parental
variety or other commonly consumed varieties with special
emphasis on important nutrients, and toxicants that occur
naturally in the food.
Information comparing the composition or characteristics of the
modified feed ingredient to that of an ingredient derived from
the parental species or other commonly utilized wild type
strains or species with special emphasis on important nutrients,
and toxicants that occur naturally in the feed product.
**References to allergenicity would likely be relevant only for ingredients intended for food-producing animals.

25. Adapting the Voluntary Consultation
Process for Microorganisms (2)
FDA Voluntary Consultation Program Proposed New Process
Information concerning the identity and function of expression
products encoded by the introduced genetic material, including
an estimate of the concentration of any expression product in
the bioengineered crop or food derived thereof.
Information concerning the identity and function of expression
products encoded by the introduced genetic material, including
an estimate of the concentration of any expression product in
the modified feed ingredient.
General description of the manufacturing process of the
modified feed ingredients.
Information regarding any known or suspected allergenicity and
toxicity of expression products and the basis for concluding that
foods containing the expression products can be safely
consumed.
Information regarding any known or suspected allergenicity**,
pathogenicity or toxicity of expression products and the basis
for concluding that modified feed ingredients containing the
expression products can be safely consumed.
Information comparing the composition or characteristics of the
bioengineered food to that of food derived from the parental
variety or other commonly consumed varieties with special
emphasis on important nutrients, and toxicants that occur
naturally in the food.
Information comparing the composition or characteristics of the
modified feed ingredient to that of an ingredient derived from
the parental species or other commonly utilized wild type
strains or species with special emphasis on important nutrients,
and toxicants that occur naturally in the feed product.
**References to allergenicity would likely be relevant only for ingredients intended for food-producing animals.

26. Adapting the Voluntary Consultation
Process for Microorganisms (3)
FDA Voluntary Consultation Program Proposed New Process
A discussion of the available information that addresses
whether the potential for the bioengineered food to induce an
allergic response has been altered by the genetic modification.
A discussion of the available information that addresses
whether the potential for the modified feed ingredient to induce
an allergic response** has been altered by the genetic
modification.
Any other information relevant to the safety and nutritional
assessment of the bioengineered food.
Any other information relevant to the safety and nutritional
assessment of the modified feed ingredient, including any
information inconsistent with the determination of safety.
Other information needed for AAFCO purposes, including:
proposed Feed Ingredient Definition and proposed label, etc.
Other information needed for GRAS purposes, including
proposed GRAS claim, basis for concluding GRAS status, etc.

27. Adapting the Voluntary Consultation
Process for Microorganisms (3)
FDA Voluntary Consultation Program Proposed New Process
A discussion of the available information that addresses
whether the potential for the bioengineered food to induce an
allergic response has been altered by the genetic modification.
A discussion of the available information that addresses
whether the potential for the modified feed ingredient to induce
an allergic response** has been altered by the genetic
modification.
Any other information relevant to the safety and nutritional
assessment of the bioengineered food.
Any other information relevant to the safety and nutritional
assessment of the modified feed ingredient, including any
information inconsistent with the determination of safety.
Other information needed for AAFCO purposes, including:
proposed Feed Ingredient Definition and proposed label, etc.
Other information needed for GRAS purposes, including
proposed GRAS claim, basis for concluding GRAS status, etc.

28. ∗ A quicker procedure for approval of modified strains of common
food/feed microorganisms is needed, particularly for use of yeast in
DDGs, where there is such a long history.
∗ For familiar microbial species, comparison of the modified strain to
wild-type should be sufficient to assess safety and avoid the need
for feeding studies.
∗ However, staffing issues at FDA CVM will continue to be the
bottleneck for all technical reviews of new feed ingredients.
∗ Can this procedure be adopted as part of ongoing “modernization”
of the Coordinated Framework?
Conclusions

29. David J. Glass, Ph.D.
D. Glass Associates, Inc.
124 Bird Street
Needham, MA 02492 USA
Phone 617-653-9945
dglass@dglassassociates.com
www.dglassassociates.com
More details on this proposal in Advanced
Biotechnology for Biofuels blog: http://wp.me/pKTxe-cn
Thank you!