Don’t Run-Off – De-oiled, Solvent-free Algae as a Sustainable Biofertilizer
R. Connelly, R. Pearsall, M. Montoya, B. Morrison, K. Kaden, K. Murphy, L. Eisenberg, M. Werst, R. Hebner
University of Texas at Austin, Center for Electromechanics, Austin, TX
OpenAlgae LLC, Austin, TX
Significance of the Study
Processed Algae Biomass Nutritional Analysis
Nutrient Content of Processed Algal Biomass
The OpenAlgae Mobile Algae Processing (MAP) unit
Oil Recovery
Concentration
N (nitrogen)
P (phosphorus)
K (potassium)
Ca (calcium)
Mg (magnesium)
Na (sodium)
Lysing
N:P:K ratio (9:5:5)
The nutritional content of processed algae is similar to chemical fertilizers.
The N:P:K ratio was determined to be (9:5:5), and also contained trace
elements necessary for plant growth.
Comparison of AB and CF on Tomato Yield and Height
Harvesting
Lysing
Oil Separations
Clean Biomass
open or closed
pH floccualtion
electric field
membrane
dried
The algae were concentrated via a pH-driven flocculation process, then lysed
via exposure to an electric field of ~9 kV/cm to liberate algal lipids. The lipids
were recovered with the OpenAlgae membrane technology without direct
contact with solvents. The de-oiled processed biomass was then dried to a
powder consistency and analyzed for nitrogen (N), phosphorus (P), potassium
(K), and protein content.
50
40
40
30
30
20
20
10
10
0
0
Height
There was no significant difference between algae- and commercial fertilizertreated plants.
Comparison of AB and CF on Basil Yield and Height
Weight in Grams
Using OpenAlgae clean processing technologies,
de-oiled, solvent-free algal biomass can serve as a
sustainable biofertilizer.
40
Algae
Commercial Fertilizer
50
*
40
30
30
20
20
10
10
0
0
Yield
Plants conditioned with algal biofertilizer (AB) will
produce yields comparable to plants conditioned
with a commercially available chemical fertilizer.
60
Height in Inches
60
Hypotheses
Height
There was no significant difference between algae- and commercial fertilizertreated plants on plant height, but algae caused significantly more yield
(*p < 0.05).
Experimental Approach
Tomatoes
Basil
Lettuce
Comparison of AB and CF on Lettuce Yield and Height
350
Weight in Grams
300
Freshwater algae , including Chlorella sp. and
Scenedesmus sp. were processed using the
OpenAlgae Mobile Algae Processing (MAP) unit
(Figure 1), then dried to a powder.
Commercial
Fertilizer
Processed
Algal
Biomass
Commercial
Fertilizer
Processed
Algal
Biomass
Commercial
Fertilizer
Processed
Algal
Biomass
The dried algae were analyzed for N:P:K and other
for nutrient content by Texas A & M AgriLife
Services.
The analyzed dried algae (9:5:5) was applied as a
biofertilizer (12.5 kg/acre) to potted vegetables
and herbs. The heights and yields of the algal
biomass-conditioned plants were monitored and
compared to plants conditioned with a commercial
fertilizer applied at the same concentration.
Algae
Commercial Fertilizer
Yield
Processed Algal Biofertilizer (AB) Greenhouse Study
50
Height in Inches
Source
50
Methods
%
8.8
5.1
5.1
0.2
0.2
0.1
350
Algae
Commercial Fertilizer
300
250
250
30
30
20
20
10
10
0
0
Yield
Height in Inches
The use of algae as a sustainable biofertilizer is
particularly appealing for many reasons. Large
scale growth of algae is accelerating and the
University of Texas/OpenAlgae has developed costeffective technologies to recover algal oils for
independent sale, then use the de-oiled, solventfree biomass as a clean and sustainable
biofertilizer. UT conducted a pilot study to evaluate
the effects of processed de-oiled algae on the
promotion of plant growth and yield. The results
showed that the heights and yield of the biomassconditioned plants were consistent with, or
improved, over plants conditioned with a
commercial fertilizer applied at the same
concentration. These data indicate that de-oiled
algal biomass processed using OpenAlgae
technologies can be used as an organic alternative
to commercial fertilizers.
Results
Number of Fruits
Today, the Haber–Bosch synthetic fertilizer process
consumes more than one percent of the energy on
Earth and is responsible for feeding roughly onethird of the world’s population. Over time,
however, aggressive fertilizer practices have
become unsustainable and have led to a number of
environmental problems and ironically, diminished
crop yields.
Methods
Height
There was no significant difference between algae- and commercial fertilizertreated plants
The soil used in this study was a commercial topsoil with no added nutrients.
In this triplicate greenhouse trial, the effect of AB on tomato, basil, and leaf
lettuce growth and yield compared to controls supplemented with the same
amount of commercial fertilizer. Plant height and yields (fruits or leaf
production) were recorded over the course of 8 weeks. At the conclusion of
the study, the bare root plants were weighed.
Conclusions
The heights and yields promoted by algae were
comparable to, or exceeded, those produced by the
commercial chemical fertilizer.
De-oiled, solvent-free algal biomass can be utilized
as a biofertilizer.
THE UNIVERSITY OF TEXAS AT AUSTIN