Lemnaceae;
from green nuisance ………
………to green technology
Dr. Marcel Jansen
Lemnaceae
Wolffia globosa
Wolffiella
gladiata
Lemna minor
Spirodela
polyrhiza
http://waynesword.palomar.edu
Smallest flowering plants
http://world-flowers-plants.blogspot.com/2011/04/smallestcrop-in-world.html
http://waynesword.palomar.edu
Small plant – fast grower!
Doubling time at UCC
Lemna minor
Lemna gibba
Landoltia puntata
Wolffia brasiliensis
2.27 day
2.18 day
2.11 day
3.35 day
Doubling time optimal conditions <20 hours
http://www.mobot.org/jwcross/duckweed/duckweed.htm
Fast growth; problem or
opportunity ?
Pennsylvania
Lake Maracaibo - Venezuela
http://www.voltairenet.org/The-Promise-of-Restitution-of
Cork
http://imageshack.us/
Lemnaceae; problem or opportunity ?
Lemnaceae in traditional /sustainable agriculture (FAO 2011)
http://www.fao.org/ag/againfo/resources/documents/DW/Dw2.htm
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
http://www.petroalgae.com/
Lemnaceae; problem or opportunity ?
Devils Lake – North Dakota – 10.000 inhab.
Tertiary wastewater treatment (N/P removal)
Plant nutrient uptake
Anaerobic microbial processes
Marriage between biology & engineering
http://www.ci.devils-lake.nd.us/departments/sewer-department.html
Phytoremediation–I - Zinc
http://www.imdb.com/

Metals and heavy metals

Lemnaceae as
bioaccumulators
–
–
Phytoremediation
Feed fortification
Zinc uptake by Lemna minor
zinc
Time in days
Linear model with first order kinetics
Based on 0.2 mg/L  BCF=1000  kg/ha/day
Zinc bioaccumulation by Lemna minor
Literature; accumulation factors Zn > 35000
Zinc in the food chain
Available for
trophic transfer
From phytoremediation to ….
……….food fortification
Zinc in Gammarus pulex fed on Lemna minor and after 24h depuration
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
TCP is phytotoxic
EC50 (µM)
Specific growth rate (day-1)
L.punctata
L.minor
L.gibba
POD activity (nmol ABTS min-1 mg-1)
Peroxidase activity in medium L. punctata
100
90
80
70
60
50
40
TCP
30
20
TCP
TCP
10
0
Landoltia punctata
Lemna minor
Lemna gibba
Response to TCP concentration that gives ca. 15% growth inhibition
UV/VIS
spectrophotometry
0.15
SpEx
0.1
Enzyme + 2,4,6, TCP
0.05
0
-0.05
0.5
HRP-C
0.4
Oxidation to 2,6 dichloro1,4 benzoquinone
0.3
0.2
0.1
0
240
280
320
Wavelength (nm)
360
400
m/z 195 TCP
(+2, +4, +6 for 37Cl)
TCP - no enzyme
LC-MS
TCP - peroxidase
Isomer dichloro
benzoquinone
Substrates for class III peroxidases
Three components of Lemnaceae response system
Lemnaceae frond
(1) Recognition
& Induction
(2) Enzyme
secretion
Trichlorophenol
(3) Oxidative detoxification by
Mono and Dichloro
benzoquinones
Class III peroxidase
Lemnaceae bioreactor?

Range of potential substrates?

TCP breakdown products?
Capacity Lemnaceae reactor?
------------------------ Secrete other desirable proteins

http://www.lemnagene.com/
………..Lemnaceae and
the Green Economy…..?
Molecular
transformation
technologies
Understanding
Physiological
potential
Engineering
solutions
DOE-JGI
genome sequence
Green technology
Protein/biofuel
Phytoremediation
Food fortification
Pharmaceuticals
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