Short presentation of some activities and results obtained in a student project based on cooperation of companies Ponika and AlgEn, and Biotechnical faculty University of Ljubljana.

1. Introduction of algae
technologies in aquaponic
food production system
Kevin Hartman, Gašper Jeršin, Katja Guček, Ažbe Žnidaršič
Mentor: dr. Vesna Miličić
39th
Conference for Students of Agriculture
Novi Sad, 20th
of November 2015

2. 1. What is aquaponics?
1. Fish waste
4. Cleaned water
3. Hydroponic subsystem
2. Biological filtration (nitrification and mineralization)
Leskovec, 2014
Aquaculture + hydroponics

3. 2. Nutrients in aquaponics
Bacterial roles:
1)Nitrification: Conversion of toxic NH4
+
/NH3 into NO3
-
.
2) Mineralization: Decomposition of organic matter and
release of nutrients by microbial activity
Aquaculture waste
solids removal
Off-line
mineralization
OR?

4. 3. Why integration of microalgae?
Algae in aquaculture:
as the main nutrition for larvae
to enhance the color of the flesh of
salmonids
to partially or totally replace the
unsustainable use of fish meal in
commercial feeds
Hydroponics:
As an organic fertilizer
To pottentialy furthermore increase
sustanability of the system.

5. Pilot aquaponic systems

6. The integrated aquponic-algae system
Fig. 1: Schematic diagram of the pilot integrated system: (1) fish tank; (2)
sedimentation for solids collection; (3) biofiltration; (4) hydroponic DWC; (5)
off-line mineralization; (6) Spirulina cultivation; (7) foliar application of
Spirulina (Hartman, 2015)

7. Experimental algae cultivation system
Experimental conditions:
2 L of M.S. medium + 10 %
inoculum (200 mL)
12/12 photoperiod
Continuous aeration and
mixing
Average culture temperature
20,6°C
Algae tested in the pre-
experiment:
Chlorella
Spirulina (Arthrospira
platensis)
Hematococcus
Mix of algae

8. Cultivation of Spirulina in the supernatant
of mineralized aquaponic solids
Fig. 3: The results of OD (optical density) measurements in three
different cultures of Spirulina cultivated in the supernatant of
mineralized aquaponic solids.

9. Pilot scale Spirulina open photo-bioreactor

10. Evaluation of Spirulina culture as foliar
fertilizer
Experimental procedure:
Cichorium intybus
Two varieties :
Leonardo and Corelli
30 plants per
treatment
Seedlings planted in
rock-wool substrate
Foliar application on 2
day period (300
ml/m2)
1 month growing
period

11. Control
Mineralized solids
Algae culture

12. Df Sum Sq Mean Sq F value Pr (>F)
Variety 1 192 192 0.083 0.77394
Treatment 2 25227 12613 5.483 0.00669**
trt Means
1 Supernatant 118.8790 A
2 Mineralized aquaponic solids 95.9350 B
3 Control 68.7135 C
Results of foliar application
1. Comparison of average weight gain between different
varieties:
2. Comparison of average weight gain between different
foliar treatments:

13. Conclusions
1. Production of algae from mineralized fish waste is
possible.
2. Better growth of plants fertilized with algae culture
compared to mineralized solids and control.
 More complete macro and micronutrient mineralization
by algal-bacterial culture than bacterial culture alone
(Mulbry, 2005)
 Production of amino acids that are beneficial for plant
culture and can possibly increase nutrient uptake and
stress response (Rai, 2002)
 Natural enzymes and hormones that have stimulative
effect on plant growth. (Shaaban et al, 2010)
3. Microbiological food safety?

14. Questions?
Authors contacts:
-www.ponnod.com
-kevin.hartman@ponnod.com
-gašper@ponnod.com
39th
Conference for Students of Agriculture
Novi Sad, 20th
of November 2015
This work has received funding from the operation which was partly financed by the European
Union through the European Social Fund. The operation is performed under the Operational
Program of Human Resources Development for the period 2007-2013, Development Priority 1:
Promoting entrepreneurship and adaptability and priority policies 1.3 Scholarship schemes.
Kevin Hartman, Gašper Jeršin, Katja Guček, Ažbe Žnidaršič
Mentor: dr. Vesna Miličić