1. Lemnaceae; from green nuisance ……… ………to green technology
Dr. Marcel Jansen

2. Lemnaceae Wolffia globosa Wolffiella gladiata Lemna minor Spirodela
polyrhiza

3. Smallest flowering plants

4. Small plant – fast grower!
Doubling time at UCC
Lemna minor day
Lemna gibba day
Landoltia puntata day
Wolffia brasiliensis 3.35 day
Doubling time optimal conditions <20 hours

5. Fast growth; problem or opportunity ?
Fast growth; problem or opportunity ?
Pennsylvania
Lake Maracaibo - Venezuela
Cork

6. Lemnaceae in traditional /sustainable agriculture (FAO 2011)
Lemnaceae; problem or opportunity ?
Lemnaceae in traditional /sustainable agriculture (FAO 2011)

7. Lemnaceae; problem or opportunity?
Protein (43% DW) feed aquaculture
Essential amino acids (Lys, Leu, Ile, Phe, Thr, Val)
Bio-crude (renewable fuel)
Technology for growth, harvesting and processing
Yield up to 4 ton FW / hectare / day
PetroAlgae Inc Florida Lemna production

8. Lemnaceae; problem or opportunity ?
Devils Lake – North Dakota – inhab.
Tertiary wastewater treatment (N/P removal)
Plant nutrient uptake
Anaerobic microbial processes
Marriage between biology & engineering

9. Phytoremediation–I - Zinc
Metals and heavy metals
Lemnaceae as bioaccumulators
Phytoremediation
Feed fortification

10. Zinc uptake by Lemna minor
Time in days
Linear model with first order kinetics

11. Zinc bioaccumulation by Lemna minor
Based on 0.2 mg/L  BCF=1000  kg/ha/day
Zinc bioaccumulation by Lemna minor
Literature; accumulation factors Zn > 35000

12. Zinc in the food chain
Available for
trophic transfer

13. From phytoremediation to …. ……….food fortification
Zinc in Gammarus pulex fed on Lemna minor and after 24h depuration

14. Phytoremediation-II - TCP
Chlorophenols
Priority pollutant
Genotoxic, mutagenic, carcinogenic
Ubiquitous in aqueous environment
Sawmills (wood impregnation agents)
Precursors / degradation products chemicals
Landfill sites
2,4,6, trichlorophenol

15. TCP is phytotoxic EC50 (µM) L.punctata L.minor L.gibba
Specific growth rate (day-1)
EC50 (µM)
L.punctata L.minor L.gibba

16. Peroxidase activity in medium L. punctata10 20 30 40 50 60 70 80 90
100
Landoltia punctata
Lemna minor
Lemna gibba
POD activity (nmol ABTS min-1 mg-1)
TCP
Response to TCP concentration that gives ca. 15% growth inhibition

17. UV/VIS spectrophotometry Enzyme + 2,4,6, TCP
Oxidation to 2,6 dichloro-1,4 benzoquinone

18. Isomer dichloro benzoquinone
m/z 195 TCP
(+2, +4, +6 for 37Cl)
TCP - no enzyme
LC-MS
TCP - peroxidase
Isomer dichloro benzoquinone

19. Substrates for class III peroxidases

20. (3) Oxidative detoxification by
Three components of Lemnaceae response system
Trichlorophenol
(1) Recognition
& Induction
(2) Enzyme secretion
Class III peroxidase
(3) Oxidative detoxification by
Mono and Dichloro
benzoquinones
Lemnaceae frond

21. Lemnaceae bioreactor? Range of potential substrates?
TCP breakdown products?
Capacity Lemnaceae reactor?
Secrete other desirable proteins

22. ………..Lemnaceae and the Green Economy…..?
Molecular
transformation
technologies
Understanding
Physiological
potential
DOE-JGI
genome sequence
Engineering
solutions
Green technology
Phytoremediation
Food fortification
Protein/biofuel
Pharmaceuticals

23. Acknowledgements
TCP (JIC, Norwich, UK)
Roger Thorneley
Lionel Hill
TCP (UCC)
Dilip Biswas (BEES)
Gillian Scannell (BEES)
Nurlan Akhmetov (Chemistry)
Dara Fitzpatrick (Chemistry)
Zinc (UCC)
Elma Lahive (BEES)
John O’Halloran (BEES)
Funding EPA and IRCSET