Post on 16-Aug-2020
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MICROALGAE CULTURE
BIO301
Dr Navid Moheimani
Algae R&D Center
What are algae? simple, non-flowering, and typically aquatic plants of a large
assemblage that includes the seaweeds and many single-
celled forms . Algae contain chlorophyll but lack true stems,
roots , leaves, and vascular tissue.
• What is photosynthesis:
• Date: 1898
synthesis of chemical compounds with the aid of radiant energy and
especially light; especially : formation of carbohydrates from carbon
dioxide and a source of hydrogen (as water) in the chlorophyll-containing
tissues of plants exposed to light (http://www.merriam-webster.com/dictionary/photosynthesis)
• It is an improbable process (uphill reaction)
Photosynthesis
Algae VS Bacteria
Sugar + O2
CO2+ H2O
Metabolism Photosynthesis
energy
Solar energy
Photosynthesis:
• What is photosynthesis:
• Date: 1898
synthesis of chemical compounds with the aid of radiant energy and
especially light; especially : formation of carbohydrates from carbon
dioxide and a source of hydrogen (as water) in the chlorophyll-containing
tissues of plants exposed to light (http://www.merriam-webster.com/dictionary/photosynthesis)
• It is an improbable process (uphill reaction)
• Oxygenic photosynthesis is one of the key fundamental biological
process which support life on the earth.
• Chloroplast are responsible for trapping light energy and convert it
to Chemical energy
Habitats
• Water (freshwater to hypersaline brines)
• Soil
• Trees etc.
• Symbionts of lichens, ferns, cycads,
sponges, molluscs, corals, flatworms etc
etc.
• Salinity:
freshwater to
saturated brines
Prokaryote
Ancestor
Heterotrophic
Flagellate
Glaucophyta
Rhodophyta
Photosynthetic
Heterotrophic
Flagellate
Cyanobacterium
S!
Flagella lost
Chlorophyta
Loss of phycobilisomes Formation of chlorophyll b Small subunit RuBisCo gene transferred to nucleus
Heterokontophyta Haptophta
Dinophyta
Cryptophyta
Primaeval Brown
Flagellate(s?) Hetrotrophic
dinoflagellate Hetrotrophic
Cryptophyte
Hetrotrophic
Haptophyte
Hetrotrophic
hetrokontophyte
S! S! S!
S!
Heterotrophic
dinoflagellate
Dinophyta
Dinophyta Dinophyta
S! S!
S!
Hetrotrophic
euglenoid
Euglenophyta
S!
Chloroplast Lost
PROKARYOTES
EUKARYOTES
Size –
~40m to ~1μm
μ
Aphanothece
Nostoc
Amphidinium
Pfiesteria - life history
Nutritional Modes
• Photoautotrophy
– Light + inorganic nutrients
– Most microalgae
• Heterotrophy
– Organic compounds (dark)
– Some species (esp. greens, euglenoids & dinos)
• Mixotrophy
– Mixture of phototrophy + heterotrophy
• Phagotrophy
ALGAL BIOTECHNOLOGY
Commercial Species
Chlorella – Japan, Taiwan (Indonesia, Czech Republic)
Spirulina – Mexico, USA, Thailand (China, India, Taiwan)
Dunaliella salina – Australia, Israel, USA (India, China)
Haematococcus – USA (India, Israel)
Late 1950’s
1960’s
1970’s
1990’s
+ Microalgae for aquaculture
Arthrospira (Spirulina) platensis
Chlorella
Dunaliella salina
Haematococcus pluvialis
Products Carotenoids
Fatty Acids
Phycobilins
Enzymes
Vitamins
Polysaccharides
Bioactive
Compounds
Biomass
Biofuels
Algae in Aquaculture
Algae in their own right
Algae as larval feeds (especially for
molluscs, crustaceans and, to a lesser
extent, fish)
Algal carotenoids as pigmenters in feed
(prawns, salmonid fish)
Algae as food in growout stage (molluscs)
N
N
H
H
HO
OH
O
O
Selected Bioactives
Cryptophycins (anti-mitotic) from Nostoc
sp. [US Patents 5945315, 5952298,
5955423]
Cyanovirins (anti-viral) [US Patents
5998587, 6015876]
Antibacterials [US Patent 5866150] from
Chaetoceros sp.
Sunscreens - carotenoids, scytonemin,
mycosporine amino acids [Canadian
Patent Application 2251457] from
Plectonema boryanum
Algae and the Environment
New applications for microalgae in wastewater
treatment higher efficieny wastewater treatment through
immobilised algae or hyperconcentrated algal cultures
new culture systems (tropical & temperate)
algal/bacterial systems in soil bioremediation
heavy metal absorption
Detection systems for toxic algae DNA probes, immunological markers
Management of algal blooms Species-specific viruses
Algae and the Environment
Algae and renewable energy Liquid fuels (biodiesel, bioethanol)
Hydrogen production
Algae in mine site revegetation
Bioenergy?
Algae Oil
Remaining Biomass
Other
Product(s)?
Saline
Water
Light Nutrients CO2 (from Power Station or
similar source)
Recycle water
Anaerobic
Digestion
Animal
feed
Methane
Nutrients
Algae
sugars Ethanol
Biodiesel
GROW
HARVEST
EXTRACT
AAllggaa PPrroodduuccttss EEssttiimmaatteedd CCoosstt
(($$UUSS//kkgg ddrryy wwtt))
Chlorella Biomass >15
Crypthecodinium DHA < 3
Dunaliella Beta-carotene < 10
Haematococcus Astaxanthin < 200
Spirulina Biomass 12 - 18
Aquaculture spp Biomass 60 - 200+
Estimated from lowest sale price of product
Culture Systems
• Extensive Open Ponds (Dunaliella salina)
• Raceway Ponds (Spirulina)
• Centre Pivot Ponds (Chlorella)
• Hybrid (Closed reactor/open raceway)
(Haematococcus pluvialis)
• Fermentor (Crypthecodinium cohnii)
• Big Bags (Aquaculture species)
• Tubular Photobioreactor (?)
Measuring Growth
In exponential growth
dx = dt (1)
Where is the ‘specific growth rate with
dimension of 1/t
Eqn 1 can be integrated (x=x0 at t=0)
x = x0et (2)
Eqn 2. can be solved to:
ln x/x0 = t (3)
When x = 2x0
ln 2 = t2 (4)
and
t2 = ln 2/ = 0.693/ (5)
Where t2 is the ‘doubling time’
Measuring Growth
Time taken for cells to double
Measuring Growth