Duckweed is the smallest flowering plant in the world, an aquatic plant which can be found in fresh water or wetlands in most corners of the world that do not freeze too frequently. Floating on or just below the surface of still or slow-moving bodies of water, many around the world perceive it as a pest, claiming it “clogs up lakes or ponds”.

1. Q. From my very limited understanding of duckweed, it
seems as though it would have great potential as aqua and
terrestrial animal feed in general?
A. Yes, while initial commercial marketing focus is on higher
value products, duckweed has been used to feed fish
and land animals for decades in integrated Asian farmer
settings. Researchers have been working with duckweed
for nearly fifty years. We know its potential to remediate
wastewater and return a large volume of high protein
biomass and exceptionally clean water. This pathway
is seen as completing the nutrient cycle, a real boon to
sustainable production of plant protein for a wide variety of
uses including aqua and terrestrial animal feeds. I love this
quote by Peter Marshall: “Waste itself is a human concept.
Everything in nature is eventually used.” Duckweed can
help farmers mimic nature in this regard, and reap feed cost
savings whilst reusing fresh water over and over.
Q. What is the state of the duckweed industry?
A. Current applications include:
1. Using the decades-old model of Asian small farm settings to
recapture animal waste nutrient streams and use the resulting
duckweed biomass as a fresh feed for ducks, fish, and swine
for feed cost savings.
Companies are developing integrated systems including
CAFO waste streams for biomethane generation and
subsequent duckweed production to be used as fresh feed
supplements for cattle, swine, and chickens. (Each species
has maximum feed inclusion rates due to each animal’s
ability to process the high percentage of water in fresh
duckweed.) Dried duckweed meal can be substituted for soya
as a protein replacement in 10-30 percent inclusion rates,
depending on the animal.
2. As a processed fishmeal replacement- lemna protein
concentrate (LPC) for swine, production initially. LPC has
gone toe-to-toe with 68 percent soy protein concentrate and
found to produce comparable results. This is powerful given
duckweed’s ability to produce at least four times the amount
of protein per hectare versus that of soya, be GMO-free, and
remediate animal waste streams at the same time.
3. Along with GreenSun Products, several companies are
working with various strains of duckweed for human nutrition
Protein levels of as high at 50 percent and above are being
reported on a dry weight basis, with vitamin and mineral
content heralded as well above average for green leafy crops.
Additional benefits include being non-GMO, gluten-free, and
organically produced. Be watching for both fresh and dried
products to hit store shelves within the next couple of years.
Q. What is the nutritional make up of duckweed?
A. While an older table, this one is fairly reliable as far as
ranges:
Organic composition in the Lemnaceae, % of dry weight
protein 6.8 — 45.0
lipid 1.8 — 9.2
crude fiber 5.7 — 16.2
carbohydrate 14.1 — 43.6
ash 12.0 — 27.6
Ms Fakhoorian suggested that the feed industry investigate
the potential for duckweed’s nearly complete amino acid
profile as being as close to animal protein as the plant
kingdom can provide. In addition she provided this quote
from Dr John Cross, author of the richly-detailed website,
The Charms of Duckweed. The protein content of duckweeds
is one of the highest in the plant kingdom, but it is dependent
on growth conditions. Typically duckweeds are rich in
leucine, threonine, valine, isoleucine and phenylalanine.
They tend to be low in cysteine, methionine, and tyrosine.”
Q. What is the state of its current usage in the livestock feed
industry? How do you believe this could be expanded?
A. Studies have shown that duckweed can be included in poultry,
swine, and cattle feedstocks at beneficial inclusion rates;
however, the practice is not yet done on a commercial scale
due to drying costs. (duckweed is 92-94 percent water on
average) Solar drying or hybrid drying has been successful on
a limited tonnage basis and this technology looks promising
for the future.
Question and Answer
with Tamra Fakhoorian,
International Lemna Assocation
Duckweed expert, Ms
Fakhoorian is a biologist,
chemist, and co-founder of
the International Lemna
Association, of which she is
the current executive director.
Three years ago Ms Fakhoorian
founded GreenSun Products,
LLC; a company that has
developed duckweed production systems, and product lines
for both pet and human nutrition.
by Peter Parker, Milling and Grain magazine
Duckweed is the smallest flowering plant in the world, an aquatic plant which can be found in fresh water or wetlands
in most corners of the world that do not freeze too frequently. Floating on or just below the surface of still or slow-moving
bodies of water, many around the world perceive it as a pest, claiming it “clogs up lakes or ponds”.
However, duckweed is anything but a pest. It is in fact somewhat more of a super plant. With properties suggesting it
is under-utilised potentially as bio-fuel; as an effective bio-remediator of waste water; it is a potent fertiliser; and most
importantly for the purposes of this article, it is a rich and sustainable source of protein with the potential for widespread use
in animal feed, aqua feed, and as a food source for humans.
DuckweedThe search for a sustainable
protein supplement for the future
58 | September 2015 - Milling and Grain
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3. Duckweed as a nutritional supplement in poultry and duck
production report better coloration of meat and yolks. Ducks,
tilapia, and carp are well able to process the moisture in fresh
duckweed and are the exception to the fresh feed limitations.
New developments in fermentation allows for preservation of
fresh feedstock with a higher percentage of digestible protein
than soya.
Protein extraction processes are rendering lemna-based
feedstocks that are becoming competitive with fishmeal
pricing. I predict lemna protein concentrates (LPC) will the
quickest route to market for aqua and terrestrial animal feeds
for the industry.
For decades, small farmers in Asia have implemented
duckweed production in integrated systems to save on feed
costs for ducks, swine, and aquaculture. Using their models,
modern CAFO can benefit by using duckweed to remediate
effluent from biomethanol digestion systems. The resulting
feedstock can be incorporated into animal or aquaculture feed
rations for cost savings.
Q. What benefits would using duckweed have over soy in
regards to protein supplementation in animal feeds?
A. Duckweed has many benefits when compared to soya:
Studies have found that lemna protein concentrate is
comparable to soy protein concentrate for swine
• Duckweed produces four to five times the protein per
hectare over soya
• Non-GMO
• Does not require the use of arable land for production
• Soy production relies primarily on artificial fertilisers,
whereas duckweed can remediate waste nutrients from
concentrated animal feedlots, thereby saving costs, cleaning
wastewater and producing a valuable feed at the same time
• Duckfeed is virtually free fresh meal when compared to
soya
Q. What limitations does duckweed have in regards to use
as an animal feed? Legal regulations? Limited research?
Expensive to produce?
A. Legal regulations: So far, while duckweed is considered a
nuisance plant in some states in the US as well as Australia,
purposeful cropping has not been an issue.
Limited research: Need more animal feed research and
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4. production research in that protein content varies with
nutrient loads and seasonal variances.
Expense: Currently, drying costs are the biggest holdup
in commercialising production. Solar and hybrid driers
can bring the costs down considerably but are early-stage
for full-scale production. Processed LPC is foreseen to be
competitive with fishmeal prices in the near future.
Q. I understand that you are the owner of GreenSun
Products, and that you have developed both pet and
human nutritional products from duckweed. Do you have
intentions of expanding into the industry of livestock
feed?
A. My team developed production, harvesting, drying and
processing systems for duckweed meal and LPC. GreenSun
initially started out in the pet food arena and has a patent
pending on formulations with limited sales in certain US
states.
A year and a half ago, GreenSun turned its attention to
research and development for human nutrition and has
recently secured funding for that sector. GreenSun has
received many inquiries as to supplying bulk tonnage of
duckweed meal for livestock, but cannot compete with
soy at this time. Long-term goals include mass production
of LPC as a fishmeal replacement. GreenSun is currently
expanding productions to include the US, Philippines, and
Mexico.
Q. What research is currently being done on the use of
duckweed as a livestock feed?
A. I just returned from the ICDRA in Japan-International
Conference on Duckweed Research and Applications.
Researchers there are primarily focused on genome
mapping and bacterial synergies for optimising production.
One study involving tilapia showed a 25 percent inclusion
rate of dried duckweed in tilapia rations but this has
been done before. There are not very many animal feed
studies at this time and this is something I am strongly
encouraging feed scientists to look into. Some of the
most recent studies have been done with regards to swine,
shrimp, and cattle.
Q. Can you please tell me more about the International
Lemna Association?
A. The International Lemna Association (ILA) works to
develop commercial production of duckweed for renewable,
sustainable products for a hungry and increasingly fresh water
limited world.
ILA was formed in June of 2012 to assist in the development
of commercially viable production and processes of
duckweed and other aquatic species for renewable,
sustainable products. Our membership consists of producers
and researchers from around the world.
We are the first trade association in the world dedicated to
large-scale production of the aquatic plant commonly known
as duckweed. The ILA seeks to bring duckweed and other
aquatic species to the limelight of sustainable crops that
out-produce terrestrial crops for protein and starches, while
utilising waste nutrients and water sources such as municipal
and industrial wastewater streams.
You can learn more at www.internationalLemnaAssociation.org
Q. Can you tell me any more interesting duckweed success
stories you would like me to include?
A. One company in Argentina, MamaGrande, is remediating
municipal wastewater lagoons with duckweed, using a
fermentation process to produce polylactic acid and using the
residue for high protein animal feedstock.
Milling and Grain - September 2015 | 61
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