Algae, a buzzword in the biofuel industry a few years ago and a diverse group of simple organisms, are the new game changer in the animal feed industry.
Text of Microalgae: A sea of opportunities for the aquaculture industry
July | August 2014 Microalgae:A sea of opportunities for the
aquaculture industry The International magazine for the aquaculture
feed industry International Aquafeed is published six times a year
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Publishers Ltd. ISSN: 1464-0058 INCORPORATING FISH FARMING
TECHNOLOGY
A lgae, a buzzword in the biofuel industry a few years ago and
a diverse group of simple organ- isms, are the new game changer in
the animal feed industry. Algae also contribute to the air we
breathe, producing nearly 50 percent of the oxygen in the
atmosphere and directly supporting the ocean life, thereby playing
a major role in global productivity. There are an estimated 800,000
species of algae that range from single-celled microor- ganisms to
multi-celled organisms, such as the 200-foot long giant kelp. Algae
produce carbohydrates, oils, protein, vitamins, pigments and
organic materials. New applications While macroalgae (seaweed)
dominate the global aquatic plant production, the microalgae
industry is growing rapidly as scientists continue to find new
appli- cations for the freshwater and marine species. Today, the
freshwater Chlorella and Arthrospira are primarily used for human
dietary supplements and ingredients for animal feed. Other species
are used for the extraction of high-valued components such as
vitamins, w-fatty acids, natural pigments and antioxidants.
Microalgae are required in larval nutrition, either fed directly in
the case of mollusks and peneid shrimp or indirectly as live prey
food in small fish larvae (Spolaoree, et al.). The nutritional
composition and biochemi- cal diversity of microalgae have
generated an enormous amount of interest in a variety of
applications. Microalgae can have high protein content with an
amino acid profile that can provide essential amino acids. The
lipid content can reach 70 percent, with a high concentration of
omega-3 and omega-6 fatty acids. Microalgae can be a valu- able
source of vitamins and minerals as well. Most commercial production
of micro- algae is done autotrophically in open out- door
circulating raceways or ponds. Under autotrophic growing
conditions, microalgae use light energy to fix carbon dioxide,
their carbon source into hydrocarbons with oxygen discharged as a
waste product. However poor light diffusion; microbial, chemical
and physical contamination; downstream processing and the growth of
zooplankton and other species are all drawbacks of an open system.
Photobioreactors (PBR) have improved productivity of autotrophic
production through the careful control of growth limiting and
environmental parameters, however PBRs have not been deemed
successful or eco- nomical for producing low cost, high volume
end-products for the feed industry. The other commercial production
meth- od in growing algae is the heterotrophic system.
Heterotrophic species get their energy from organic carbon
compounds in much the same way as yeast, bacteria and animals. By
eliminating light from the MICROALGAE: A sea of opportunities for
the aquaculture industry by Dr Keith Filer, Alltech High-quality
micro-algae concentrates used in early developmental aquafeeds by
Pieter Boelens, Chief Operation Officer, Evodos M icro-algae
provide an impor- tant direct or indirect feed source for early
developmen- tal stages of many farmed finfish, shellfish and
invertebrate species. Hatcheries typically cultivate micro-algae
in-house, but commercial concentrates are starting to be used, as a
substitute. Commercially available concentrates offer a convenient
source for micro-algae hatcheries. The number of micro-algae
producers delivering algae concentrates to the hatcheries is
growing. Only those micro-algae producers, which are delivering the
right quality concen- trate, are successful. From an aquaculture
perspective, the key desire attributes for micro-algae concentrates
are: High cell concentration without dam- aged cells Increased
shelf life Easy to suspend uniformly in water Regularly available
and affordable The company Evodos focuses on 'harvesting'
micro-algae concentrates out of open ponds and photo bioreactors
(PBR's) for aquafeed. With the Evodos micro-algae harvesting
solution you harvest a high quality micro-algae concentrate, the
micro-algae cells are intact and undamaged. During the harvesting
process, the micro- algae dont change in structure and tem-
perature. All valuable components inside the micro-algae cells are
fully retained. Key micro-algae strains Evodos has a growing client
base by achiev- ing a very high quality output with micro-algae
species that play an important role in the Aquaculture market, like
Dunaliella, Tetraselmis, Nannochloropsis, Chlorella, Diatoms and
more. Today, these key micro-algae strains are avail- able as
concentrates processed by Evodos units. These are marketed as total
replacements for living micro-algae or serve as a back-up against
crashes and out-of-season shortages or supple- ment to live
micro-algae produced in-house. Available micro-algae concentrates
also enables smaller enterprise to operate without an in-house
micro-algae production capacity. One of the successful micro-algae
produc- ers is Tomalgae, a biotech company which develops
micro-algae based products for the aquaculture market. With the
Evodos units, Tomalgae produces high quality micro-algae
concentrate mainly for the larval stage. The diatoms belong to one
of the most economically important groups of algae. For various
applications, it is often very important that while algae cultures
are concen- trated via centrifugation, the cells are not dam- aged
and keep their integrity after the processing. Traditional methods
of centrifugation typi- cally bring a serious damage to the cells
break- ing or opening their frustules that usually dra- matically
reduces the quality of the microalgal biomass obtained. In
contrast, recently I repeat- edly had a chance to process large
volumes of diatoms using The Evodos Dynamic Settler. The results of
these tests proved to be uniformly identical: the perfect quality
of con- centrated microalgal (diatom) paste no dia- toms cells were
detected that exhibited any signs of mechanical damage, says
Professor Viktor Chepurnov, Tomalgae. With the Evodos micro-algae
harvesting solution algae producers can produce the right quality
micro-algae concentrates neces- sary for the aquaculture market:
high quality micro-algae concentrate that is equal to the quality
of living micro-algae. www.evodos.eu CASE STUDY 30 | INTERNATIONAL
AQUAFEED | July-August 2014 FEATURE
production process, any fermenter (such as those used for
production of medicines, beverages and food additives) can be used
for heterotrophic algal growth. Reaching 100,000 liters in size,
these fermenters can generate large volumes of highly productive
cultures making them less expensive than the autotrophic system.
One of the main differences between autotrophic and heterotrophic
systems is the added nutritional benefits from heterotrophic algae.
The heterotrophic method maintains a closed, controlled system that
provides a more consistent, traceable and pure algal product that
is more beneficial for the feed industry. For example, by
manipulating the physical and chemical properties of the cul- tural
medium, several species of microalgae can overproduce and
accumulate higher levels of specific fatty acids. Xu et. al (2006)
dem- onstrated that C. protothecoides had a lipid content as high
as 55 percent, approximately four times greater than when grown
auto- trophically. Omega-3 fatty acid In another study, Barclay et.
al (1994) showed that omega-3 fatty acid productiv- ity was two to
three times higher when produced in heterotrophic rather than auto-
trophic conditions. Microalgae that contain large quantities of
high quality eicosapentaenoic acid (EPA) and docosahexaenoic acid
(DHA)are now being commercialised as sustainable alternative
sources to fish oil. By providing a clean and consistent source of
omega-3 fatty acids and high quality protein, heterotrophic
microalgae offer more nutrition components to a diet than the
autotrophic method. The Marine Ingredients Organization (IFFO) sees
microalgae as the most promising and sustainable alternative
sources to EPA and DHA in fish oil. Algal oils are now being
commercialized as sustainable alternative sources to fish oils.
They have been shown to be nutritionally equivalent and can
successfully enrich larval feed and replace fish oil in fish diets.
Alltech has focused its research efforts on algae for the past five
years, purchasing one of the largest heterotrophically grown micro-
algae facilities in 2010. The 100,000-square foot state-of-the art
facility in Winchester, Kentucky, uses proprietary algal technology
to process heterotrophic algae because of its nutritional benefits.
A series of experiments in tilapia and trout were performed to
evaluate the nutritional value of a high DHA strain of alga (SP1)
pro- duced by Alltechs Algae facility. The algae were included at
low levels in tilapia diets to evaluate the uptake of DHA in the
fillet and added at high levels in trout to determine the impact on
performance. The tilapia fed 0.4 percent SP1 in the diet had higher
DHA levels at the end of the 13-week feeding trial. The 15 percent
SP1 inclusion rate in the rainbow trout diet improved weight gain
and also increased DHA levels in the fillet. These trials indicated
that heterotrophic microalgae can be included in tilapia and trout
diets to increase DHA level in fish meat as well as improve fish
performance. Work will continue with this strain of alga to define
the nutritional value in marine species and shrimp. The benefits of
feeding microalgae A two-fold contribution, the aquaculture indus-
try can see the benefits of feeding microalgae to fish as well as
marketing the enriched product to consumers. This can mean
improving return while creating a healthier population of both
humans and aquaculture all at the same time. Beside the nutritional
improvement that microalgae can bring to fish and food, it is one
of the only biomass material that allows production with daily
harvest all year round. This could bring more security to an ever-
changing market, and provide some options for the aquaculture
industry, especially when fish oil supplies are depleting as it
continues to be sold to the human side for a higher dollar amount.
July-August 2014 | INTERNATIONAL AQUAFEED | 31 FEATURE Algae
Harvesting Excellence Evodos delivers micro-algae harvesting
solutions Harvest a high quality concentrate equal to living
micro-algae Micro-algae is harvested intact and undamaged which
increases shelf life Proven replacement or supplement for living
micro-algae No chemicals or additives needed for harvesting W
www.evodos.eu P +31 76 571 1170 E [email protected]
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Microalgae: A sea of opportunities for the aquaculture industry
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