bioenergy from photosynthetic algae and...

ANU Energy Change Institute energy.anu.edu.au

Bioenergy from photosynthetic algae and cyanobacteria.

Associate Professor Michael Djordjevic

Research School of Biology

http://biology.anu.edu.au/michael_djordjevic/

Presenter

Presentation Notes

In the short time I have today I would like to assess the prospects of deriving credible source of bioenergy from what are called photosynthetic microalgae: cyanobacterial sources (bacteria) algae that are more akin to single celled microscopic plants.


Multitude of Global Research and Development Initiatives

Determine the suitability and feasibility of using aquatic photosynthetic

microorganisms as a source of renewable bioenergy.

Presenter

Presentation Notes

Many global research and development initiatives have aimed to address the following issue: Can aquatic photosynthetic microorganism be used as a credible source of renewable bioenergy? Can there basic ability to make high energy products be improved. First lets explore why would this might be a reasonable proposition in the first place?


100 billion tons of carbon per year

Satellite Sensed Photosynthesis

Presenter

Presentation Notes

On of the inspirations for this endeavour is derived from this assessment of global photosynthesis derived from satellite imaging. Photosynthetic organisms are responsible each year for the capture of 100 billion tons of carbon per year. To put this number into some kind of perspective: Australian exports 250 million tons of Coal and global coal consumption of 5 billion tons. World forests responsible for about half.



About half occurs in oceans: phytoplankton

Presenter

Presentation Notes

What is less appreciated is that the other half occurs in the oceans. To see this on the map one has to look to the red orange yellow and bright green areas in the worlds oceans and lakes. Hot spots at mouth of major river systems (Amazon Mississippi, Congo and also in several in land lakes in Africa, N America, Black and Caspian seas. This is done by phytoplankton: small microscopic photosynthesising bacterial cells and plant like cells.



About half occurs in oceans: phytoplankton • cyanobacteria • algae

Presenter

Presentation Notes

Half by photosynthetic cyanobacteria (bacteria like) half by small microscopic plant like microscopic organisms. Can this organisms be harnessed in an industrialised process? Requires much less area?

Energy from microalgae?

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S

• Diverse range of energy-rich compound compounds e.g. • Lipid (L) and lipid-like (eg hydrocarbon) (Lipid readily converted to ‘drop in’ fuel) • Starch (S) (Starch converted to ethanol)

• Can grow, under ideal conditions, faster than terrestrial plants and all the biomass contains the energy rich compounds (unlike plants). Also no lignin. • Also contain other compounds of interest with medicinal or food-related applications • Energy-rich compounds vary (negligible to 20-30% of dry weight) • Energy cost in growing and extracting internal lipid and hydrocarbon-like molecules • Can they be harnessed in an industrial setting and can these strain be improved?

Chlamydomonas

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L L

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Chlamydomonas

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S S S

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Presenter

Presentation Notes

Agla and cyanobacteria have other features of interest that might make them suitable sources of feedstock for biofuel production. Produce energy rich compounds. For

Improving Energy from microalgae?

•Biosolar group. Can microalgae be improved?

• Dr. Djordjevic (Algae), Gabriel James (Ph.D) • Dr. Hiller (Thermophilic cyanobacteria), Duncan Fitzpatrick (Ph.D) • Dr. Price (Cyanobacteria), • Dr. Hocart (Mass spectrometry facility).

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Chlamydomonas

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S S S

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S L

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Presenter

Presentation Notes

The Biosolar group has focused on this question. Involves a collaboration between several laboratories.


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cc-124 cc-125 I7 BAF-J5

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l Fat

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cid

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ry C

ell W

eigh

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N+

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600 - 700% increase in lipid content

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Further yield increases can be achieved by optimising growth temperature: ~ 70% of dry weight

Can microalgae be improved: metabolic engineering

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Chlamydomonas

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S L L

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James et al 2011 James et al 2012

Presenter

Presentation Notes

However some strains accumulate much higher amounts of oil. Tend to be the plant like algae. Some do so naturally; other need special conditions and or some metabolic engineering. Several research groups have successfully manipulate microalgae (those most akin to land plants) to accumulate higher levels. Need both starvation of nitrogen (food source) and some metabolic engineering to do this


Cyanobacteria

• Cyanobacteria: highly productive photosynthetic bacteria (=25% global photosynthesis)

• fast growth rates, high biomass yields and accumulate glycogen, poly-Beta hydroxybuterates but moderate and diverse lipid (~10-20% dry weight)

•Have efficient CO2 uptake/concentrating mechanism

• allows inorganic carbon uptake • some strains fix atmospheric nitrogen • largely ANU research

Plasma membrane (inner) Thylakoid

membrane

Carboxysome

Restricted CO2 leakage

Outer membrane

Rubisco 1B

CA

PGA

ccmKLMN, ccmORbcLS(1B), CcaA HCO3

-

CO2

CO2

NADPH

HCO3-HCO3

-

NADPH

HCO3-

HCO3-CO2

NDH-13

NDH-14

BicA

SbtA Na+

HCO3-HCO3

-

Na+

HCO3-

ATPBCT1

β- Carboxysomes

Ci transporters

HCO3-

Freshwater β-Cyanobacteria

Presenter

Presentation Notes

Anothe rtype of organism being assessed is cyanobacteria. Initially shunned because they have less lipid accumulation. But hey have other redeeming features that has rekindle interest in them. Fast grwoth rates and biomass yields can be much higher than plant like phytoplankton. Already contribute to about 25% of global photosynthesis. CCM is a bonus. Already built in.


• Can the metabolic engineering success from algae be translated to cyanobacteria?

• So far: NO.

• Does not lead to a great increase in lipid production inside cells.

Cyanobacteria: Engineering Biofuel Production by Gene manipulation


• Entire metabolic pathways can and have been introduced into cyanobacteria

• Genes can be easily knocked out and added

• Can biofuel feedstock production be increased by gene manipulation?

• Possible R and D solution : manipulate cyanobacteria to secrete fatty acids

Synechococcus PCC7942 carboxysome genes

K1 L M N O L S

ccm genes Rubisco genes

M35

Cyanobacteria: Amenable to Genetic Manipulation

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Global Research Initiatives to maximise production of High Energy Products from Algae

Can algae and cyanobacterial strains be utilised in commercial processes to amass enough biomass so that the quantity of the high energy products can generate a sustainable bioenergy source?

a) Higher yield of high energy feedstock per cell b) High biomass per unit time c) Minimise infrastructure costs d) Lower input costs e) Lower extraction/conversion cost

Presenter

Presentation Notes

Apart from our initiatives global interest in algae. So apart from maximising amoutn of suiable biofuel per cell, one also needs a lot of biomass from which to extract this fuel.


• Numerous Australian and International R & D initiatives to engineer/optimise or generate elite strains or to produce alternative fuels

• Australian Higher Ed : (Brisbane [UQ], Nth. Qld, Melbourne, Adelaide [SARDI, University of Adelaide], Perth [Murdoch], Canberra [ANU], Hobart [CSIRO])

• Maximising biomass is critical and well as production per cell • some local “super stains” have been identified (SARDI).

• Best conditions in pilot plants:

• produces 20-25 g useful organic weight of algae per m2 per day has been reported relying primarily on photosynthesis to make energy to drive growth • but not scaled up to massive industrial production

Initiatives to produce algae for biofuels

Presenter

Presentation Notes

Extensive world-wide interest in using phytoplankton to produce biofuels. In australia: ANU/CSIRO collaboration recently begun (Price hillier and Blackman)


Initiatives to produce algae for biofuels and specialised oils

Solazyme Sapphire Energy: “Green Crude Farm”

Algae.tec Clean algae biofuel project

Presenter

Presentation Notes

Extensive world-wide interest in using phytoplankton to produce biofuels. In australia: ANU/CSIRO collaboration recently begun (Price hillier and Blackman)

Considerations:

• Nutrient requirements • Water requirement/movement • Extraction cost • Purification/conversion costs • Requirements for land

Absolute best case scenario with current technology:

• $84/bbl • (13-64 ha /MW = 50-20 g per m2 day) • ~ 50,000 L ha per year

Vision for outdoor scale up

Assumptions: CO2 capture from coal fired power station, non arable cheap land, continuous production, waste-water utilisation, possibility for co-products, recycling of nutrients in residual biomass, control of evaporation.

• Stephens et al. Nature Biotech. 28: 126-128, 2010. • Lundquist et al. A realistic technology and engineering assessment of Algal Biofuel production. Energy . Bioscience Institute, University of California Berkeley Oct 2010

600-39,000 sq km estimated

Presenter

Presentation Notes

Large scale growth in shallow ponds CO2 enriched ready source of suitable water. Barriers to making this happen . Energy cost in moving the water, extracting microalgae purifying and processing energy rich compounds and keeping production constant with fidelity (strain do not collapse or get eaten by predators or affected by viruses).


Alternative Assessment “National Research Council (NRC) of the U.S. National Academies says that large-scale production of biofuels from algae is untenable with existing technology, ...would require the use of too much water, energy, and fertilizer”.....

...scaling up to 39 billion litres using current technology... “would require an unsustainable level of inputs” ....

“Growers would also have to add between 6 million and 15 million metric tons of nitrogen and between 1 million and 2 million metric tons of phosphorus to produce 39 billion liters of algal biofuels” ......(44% and 107% of the total use of nitrogen in the United States, and between 20% and 51% of the nation's phosphorus use for agriculture).

..but the NRC did “not consider any one of these sustainability concerns a definitive barrier to sustainable development of algal biofuels”. (e.g. Nutrient/ water recycling)

(R. Service. “Large-Scale Algae Biofuels Currently Unsustainable, New Report Concludes”. Science. 24th October, 2012).


• Photosynthetic microorganism are attractive systems to produce high energy storage molecules

• Algae: are capable of storing significant amount of cellular mass as lipid

• Algae: grow slowly and require significant input of nitrogen to support growth but under optimal conditions could provide a source of biofuel

• Cyanobacteria: grow much more vigorously

• Cyanobacteria: Tend to store energy as carbohydrate rather than lipid and lipid-like molecules

• Cyanobacteria: Are genetically tractable.

• A possible future initiative: Manipulate photosynthetic microorganisms to secrete fatty acids or other lipids/hydrocarbons/sugars. This may overcome some of the barriers to effective scale up.

• Nutrient /water/energy issues required for scale up need addressing.

Perspectives

Hydrogen from micro algae?

Presenter

Presentation Notes

Alternative approaches. Strains engineered to produce hydrogen gas (alternative high energy product) on a continual basis.

No hydrogen fuel infrastructure

Presenter

Presentation Notes

Attracted wide interest in Australia and Internationally Aust-German collaboration./ However, still early days and no h fuel infrastructure in place.


Plasma membrane (inner) Thylakoid

membrane

Carboxysome

Restricted CO2 leakage

Outer membrane

Rubisco 1B

CA

PGA

ccmKLMN, ccmORbcLS(1B), CcaA HCO3

-

CO2

CO2

NADPH

HCO3-HCO3

-

NADPH

HCO3-

HCO3-CO2

NDH-13

NDH-14

BicA

SbtA Na+

HCO3-HCO3

-

Na+

HCO3-

ATPBCT1

β- Carboxysomes

Ci transporters

HCO3-

Freshwater β-Cyanobacteria

0.5 µM

carboxysomes

thylakoids

Carboxysome ~ 150 nm dia.

Cyanobacterial CO2 concentrating mechanism or CCM (largely ANU research)

Presenter

Presentation Notes

Single cyanobacterial cell. Unique take up bicarbonate from environment and CO2. also have carboxysomes concentrate the absorbed carbon and convert it higher energy compounds

bioenergy from photosynthetic algae and...

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