1. Hydrogen production in algal-bacterial cultures
Dr. Gergely Ernő Lakatos

2. Stress induced algal hydorgen production methodes
Stress induced algal hydrogen production methodes under illumination:
Sulfur
Nitrogen
Phosphate
Magnesium
DEPRIVATION
Disadvantages:
Separated biomass and hydrogen production OR
Precise addition of the deprived nutrient
Slow hydrogen production initiation (1-8 days)
Inhibited biomass growth

3. Setup of algal-bacterial hydrogen producing system
Tris-Acetate-Phosphate media
Carbon source:
acetic acid. O2
CO2

4. Obtained results
Establishing pure algal and bacterial cultures from infected algal cultures
Determination of the algal and bacterial strains
Algae:
Chlamydomonas
Chlorella
Scenedesmus
Bacteria:
Wilde types (detected in the algae culture):
Rhodcoccus sp.
Brevundimonas sp.
Leifsonia sp.

5. Obtained results Advantges:
Mixed biomass production during hydrogen evolution
Elevated algal biomass production by the addition of bacterial partner
Cooperation: biogas production by the produced algal-bacterial biomass
Fast oxygen consumption by the bacterial partner
Fast initiation of hydrogen production in 1-4 hours
Disadvantages:
Short hydrogen production time length
Low hydrogen ptoduction rates

6. Obtained results Elevation of hydrogen production rate by:
the application of hydrogenase defficient bacterial partner
Artificially added strains (wild and hydrogenase defficient):
Esherichia coli
Ralstonia eutropha
the optimization of gas-to-liquid phase ratios
the optimization of culture optical density
the reduction of algal cell size
Optimized hydrogen production for daily harvesting
(~100 ml H2 L-1 culture day-1), comperable hydrogen yield with sulfur-deprived results

7. Short term aim
Establishing a semi-continuous hydrogen and biomass producing system in small scale (40 ml).
Hydrogen release by purging of the headspace
1 day H2 H2
ambient air H2 H2 H2
low biomass content
high biomass content
acetic acid addition
40 mL sealed bottles
Biomass harvesting

8. Long term aim 1.
Finding cheap carbon source: using carbon dioxide as a sole carbon source.
Hydrogen release by air purging
1 day H2 H2
ambient air H2 H2 H2
low biomass content
high biomass content
CO2 addition
40 mL sealed bottles
Biomass harvesting

9. Long term aim 2.
Finding cheap carbon source: using diluted biogas sludge supernatant as a media for biomass and hydrogen production.
biogas production
biomass fermentation
filtration
biomass production
hydrogen production
dilution
algae addition

10. Thank you for your attention