course project = algal lipid production decide which algae to study

Course Project = Algal Lipid Production1)Decide which algae to study

http://www.cbs.umn.edu/lab/wackett/links/oil2)Learn more about cell walls and lipid synthesis3)Design some experiments4)See where they lead us


http://www.cbs.umn.edu/lab/wackett/links/oilNext assignment: each pick an alga and product and convince the group in 5-10 minutes why your choice is best. Next Wed?



Potential experiments1.Effects of environment on lipid production



Potential experiments1.Effects of environment on lipid production•pCO2




•temperature




•Temperature•Light quantity




•Temperature•Light quantity• Intensity




•Temperature•Light quantity• Intensity• Duration (= photoperiod=daylength)




•Temperature•Light quantity•Light quality




•Temperature•Light quantity•Light quality = color(s)

Potential experiments1.Effects of environment on lipid production• pCO2

• Temperature• Light quantity• Light quality = color(s)• Nutrition


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N• P


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N• P• K


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N• P• K• S


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N• P• K• S• Ca


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N• P• K• S• Ca• Fe


• Temperature• Light quantity• Light quality = color(s)• Nutrition• N• P• K• S• Ca• Fe• Mg

Potential experiments1.Effects of environment on lipid production• Nutrition• N• P• K• S• Ca• Fe• Mg• micronutrients

Potential experiments1.Effects of environment on lipid production• Nutrition• N• P• K• S• Ca• Fe• Mg• Micronutrients

• Vitamins

WATER• Plants' most important chemical• most often limits productivity

•Gives cells shape• Dissolves many chem: most biochem occurs in water•Constantly lose water due to PS (1000 H2O/CO2)

Plant Water Uptake

Water is drawn through plants along the SPAC, relying on adhesion & cohesion (&surface tension) to draw water from the soil into the air

Water potentialWater moves to lower its potentialDepends on:• [H2O]: s (osmotic potential)

• Pressure p

• Gravity g

w = s +p + g

Measuring water potentialP (pressure potential) is hard!• Pressure bomb = most common techniqueOthers include pressure transducers, xylem probesTherefore disagree about H2Otransport in xylem

Water transportTherefore disagree about H2Otransport in xylem• Driving force = evaporation in leaves (evapotranspiration) • Continuous H2O column from leaf to root draws up replacement H2O from soil (SPAC)

Water transportDriving force = evaporation in leaves (evapotranspiration)• Continuous H2O column from leaf to root draws up replacement H2O • Exact mech controversial

Water transportDriving force = evaporation in leaves

(evapotranspiration)• Continuous H2O column from leaf to root draws up replacement H2O • Exact mech controversialPath starts at root hairs

Water transportPath starts at root hairs• Must take water from soil

Measuring water potentialPath starts at root hairs• Must take water from soil• Ease depends on availability & how tightly it is bound

Measuring water potentialPath starts at root hairs• Must take water from soil• Ease depends on availability & how tightly it is bound• Binding depends on particle size & chem

Measuring water potentialMust take water from soil• Ease depends on availability & how tightly it is bound• Binding depends on particle size & chem• Availability depends on amount in soil pores

Measuring water potentialAvailability depends on amount in soil pores• Saturation: completely full

Measuring water potentialAvailability depends on amount in soil pores• Saturation: completely full• Field capacity: amount left after gravity has drained

excess

Measuring water potentialAvailability depends on amount in soil pores• Saturation: completely full• Field capacity: amount left after gravity has drained

excess• Permanent wilting point: amount where soil water

potential is too negative for plants to take it up

Water movement in plantsWater enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermis

Water movement in plantsWater enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermisMust enter endodermal cell

Water TransportWater enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermisMust enter endodermal cellWhy flooded plants wilt!

Water TransportWater enters via root hairs mainly through apoplast until hits Casparian strip : hydrophobic barrier in cell walls of endodermisMust enter endodermal cellWhy flooded plants wilt!Controls solutes

Water TransportMust enter endodermal cellControls solutesPasses water & nutrients to xylem

Water TransportPasses water & nutrients to xylems of xylem makes root pressure

Water TransportPasses water & nutrients to xylems of xylem makes root pressure

Causes guttation: pumping water into shoot

Water Transport Passes water & nutrients to xylems of xylem makes root pressure

Causes guttation: pumping water into shootMost water enters near root tips

Water TransportMost water enters near root tipsXylem is dead! Pipes for moving water from root to shoot

Water TransportMost water enters near root tipsXylem is dead! Pipes for moving water from root to shootMost movement is bulk flow

Water TransportXylem is dead! Pipes for moving water from root to shootMost movement is bulk flow• adhesion to cell wall helps

Water TransportXylem is dead! Pipes for moving water from root to shootMost movement is bulk flow• adhesion to cell wall helps•Especially if column is broken by cavitation (forms embolisms)

Water TransportMost movement is bulk flow• adhesion to cell wall helps•Especially if column broken by cavitationIn leaf water passes to mesophyll

Water TransportMost movement is bulk flow• adhesion to cell wall helps•Especially if column broken by cavitationIn leaf water passes to mesophyll, then to air via stomates

Water TransportIn leaf water passes to mesophyll, then to air via stomatesDriving force = vapor pressure deficit (VPD)• air dryness

Water TransportIn leaf water passes to mesophyll, then to air via stomatesDriving force = vapor pressure deficit (VPD)• air dryness•∆ H2O vapor pressure [H2O(g)]& saturated H2O vapor pressure

Water TransportIn leaf water passes to mesophyll, then to air via stomatesDriving force = vapor pressure deficit (VPD)• air dryness•∆ H2O vapor pressure [H2O(g)]& saturated H2O vapor pressure• saturated H2O vapor pressurevaries with T, so RH depends on T

Water TransportIn leaf water passes to mesophyll, then to air via stomatesDriving force = vapor pressure deficit (VPD)• air dryness•∆ H2O vapor pressure [H2O(g)]& saturated H2O vapor pressure• saturated H2O vapor pressurevaries with T, so RH depends on T• VPD is independent of T: says how fast plants lose H2O at any T

Water TransportIn leaf water passes to mesophyll, then to air via stomatesDriving force = vapor pressure deficit (VPD)• air drynessRate depends on pathway resistances

Water Transport Rate depends on pathway resistances• stomatal resistance

Water Transport Rate depends on pathway resistances• stomatal resistance• Controlled by opening/closing

Lipid metabolismMost are glycerolipids: fatty acids bonded to glycerol

GLYCEROLIPIDS

Triacylglycerols = FAs on all 3 C

• store energy

GLYCEROLIPIDS

Bond FA to glycerol

Diacylglycerols = FAs on 2 Cs, headgroup on C 3

GLYCEROLIPIDS

Diacylglycerols = FAs on 2 Cs, headgroup on C 3Form bilayers in water

Lipid metabolismUnique aspects inplantsMake fatty acids by same set of reactions, but in plastids with a prokaryotic fatty acid synthase12 proteins, cf one multifunctional protein

Lipid metabolismMake fatty acids in plastids with a prokaryotic FAS• 12 proteins, instead of one multifunctional protein• Assemble some lipids in CP, others in ER

Lipid metabolismMake fatty acids in plastids with a prokaryotic FAS• 12 proteins, instead of one multifunctional protein• Assemble some lipids in CP, others in ER• Acetyl-CoA carboxylase is also prokaryotic = 4

subunits, except in grasses (profoxydim & other grass herbicides inhibit ACCase)

Lipid metabolism• Acetyl-CoA carboxylase is also prokaryotic = 4


• Same biochem, but difflocation and enzymes



• Same biochem, but difflocation and enzymes• In light cp make lots of NADPH, and leaves are main sinks for FA


subunits, except in grasses (profoxydim & other herbicides inhibit ACCase)

• Same biochem, but difflocation and enzymes• In light cp make lots of NADPH, and leaves are main sinks for FA• But, each cell makesits own FA, so NADPHin other cells comes fromPentose-Pi shunt

Lipid metabolismSource of acetyl-CoA is controversial• Most comes from plastid PDH

Lipid metabolismSource of acetyl-CoA is controversial• Most comes from plastid PDH• Some comes from cytoplasmic acetate; activated in cp• Also used to makesterols, some aminoacids, many others

Lipid metabolismSource of acetyl-CoA is controversial• Most comes from plastid PDH• Some comes from cytoplasmic acetate; activated in cp• Also used to make sterols, some amino acids, many others• Why ACCase is “committed step”

Lipid metabolismAssemble some lipids in CP, others in ER• “16:3 plants” assemble lipids in cp using FA-ACP =

prokaryotic pathway (“primitive”)

Lipid metabolism“16:3 plants” assemble lipids in cp using FA-ACP =

prokaryotic pathway (“primitive”)“18:3 plants” export FA, assemble lipids in ER using FA-

CoA = eukaryotic pathway (“advanced”)

Lipid metabolism“16:3 plants” assemble lipids in cp using FA-ACP =

prokaryotic pathway (“primitive”)“18:3 plants” export FA, assemble lipids in ER using FA-

CoA = eukaryotic pathway (“advanced”) Substrates for most desaturases are lipids, not FA!

Lipid metabolismUnique aspects in plantsChloroplasts have lots of galactolipids: sugar linked directly to diacylglycerol

Lipid metabolismUnique aspects in plantsChloroplasts have lots of galactolipids: sugar linked directly to diacylglycerol: saves PO4

Lipid metabolismUnique aspects in plantsChloroplasts have lots of galactolipids: sugar linked

directly to diacylglycerol : saves PO4

A) MGDG (Monogalactosyl diacylglycerol) 50% cp-> most abundant lipid on earth!

Lipid metabolismUnique aspects in plantsChloroplasts have lots of galactolipids: sugar linked


A) MGDG (Monogalactosyl diacylglycerol) 50% cpB) DGDG (Digalactosyl diacylglycerol) 28% cp

Lipid metabolismChloroplasts have lots of galactolipids: sugar linked


A) MGDG (Monogalactosyl diacylglycerol) 50% cpB) DGDG (Digalactosyl diacylglycerol) 28% cpC) SQDG ( Sulphoquinovosyldiacylglycerol) 16% cp



A) MGDG (Monogalactosyl diacylglycerol) 50% cpB) DGDG (Digalactosyl diacylglycerol) 28% cpC) SQDG ( Sulphoquinovosyldiacylglycerol) 16% cp• Very unsaturated!



A) MGDG (Monogalactosyl diacylglycerol) 50% cpB) DGDG (Digalactosyl diacylglycerol) 28% cpC) SQDG ( Sulphoquinovosyldiacylglycerol) 16% cp• Very unsaturated!• Makes membranes very fluid



A) MGDG (Monogalactosyl diacylglycerol) 50% cpB) DGDG (Digalactosyl diacylglycerol) 28% cpC) SQDG ( Sulphoquinovosyldiacylglycerol) 16% cp• Very unsaturated!• Makes membranes very fluid• Source of 3 FA

Lipid metabolismUnique aspects in plants1) Make fatty acids in plastids2) large amounts of galactolipids3) Oleosomes: oil-storing organelles with only outer leaflet

Lipid metabolismOleosomes: oil-storing organelles with only outer leaflet • Put oils between the leaflets as they are made

Lipid metabolismOleosomes: oil-storing organelles with only outer leaflet • Put oils between the leaflets as they are made• Add oleosin proteins to outside: curve the membrane

Lipid metabolismOleosomes: oil-storing organelles with only outer leaflet • Put oils between the leaflets as they are made• Add oleosin proteins to outside: curve the membrane• Oils often have unusual fatty acids

Lipid metabolismUse fats to store carbon as well as energy!!??• Recover C via glyoxylate cycle & gluconeogenesis

Lipid metabolismBiological roles• Plasma membrane lipids helpsurvive freezing

Lipid metabolismBiological roles• Plasma membrane lipids helpsurvive freezing• Unacclimated cells vesiculate as they lose water & pop when it returns

Lipid metabolismBiological roles• Plasma membrane lipids helpsurvive freezing• Unacclimated cells vesiculate as they lose water & pop when it returns• Acclimated cells shrivel & reswell

Lipid metabolismBiological roles• Plasma membrane lipids help survive freezing• Mito lipid composition may also influence chilling

sensitivity• CS plants (eg bananas) are damaged at 10˚ C

Lipid metabolismBiological roles• Plasma membrane lipids help survive freezing• Mito lipid composition may also influence chilling

sensitivity• CS plants (eg bananas) are damaged at 10˚ C• Mito show defects at <10˚ C not seen in other plants

Lipid metabolismCS plants (eg bananas) are damaged at 10˚ C• Mito show defects at <10˚ C not seen in other plants• Membrane lipids show phase changes at these T

Lipid metabolismCS plants (eg bananas) are damaged at 10˚ C• Mito show defects at <10˚ C not seen in other plants• Membrane lipids show phase changes at these T• Blamed on saturated PG

Lipid metabolismBiological (& commercial) roles• Plasma membrane lipids help survive freezing• Mito lipid composition influences chilling sensitivity• Mito show defects at <10˚ C not seen in other plants• unsaturated FA did not fix CS, but saturated FA

made it worse: reason for GM desaturases

Lipid metabolismOther commercial aspects• Yield and quality of seed oil is very important:12

million tons/year

Lipid metabolismOther commercial aspects• Yield and quality (especially unsaturation) of seed oil is

very important:12 million tons/year• Want more double bonds, especially -3, for health• Want less double bonds for shelf life and taste• Each double bond increases p(oxidation) 40x

Lipid metabolismOther commercial aspects• Yield and quality (especially unsaturation) of seed oil is

very important:12 million tons/year• Want more double bonds, especially -3, for health• Want less double bonds for shelf life and taste• Each double bond increases p(oxidation) 40x• Have GM oils with more & less double bonds

Lipid metabolismOther commercial aspects• Yield and quality of seed oil is very important:12

million tons/year• Also have markets for many specialized oils

Lipid metabolismOther commercial aspects• Yield and quality of seed oil is very important• Also have markets for many specialized oils• Have genetically-engineered many crops to alter

seed oils or produce specific fats

Lipid metabolismBiofuels are now very fashionable• Biodiesel = fatty acid methyl esters• Trans-esterify oils to make them volatile

Lipid metabolismBiofuels are now very fashionable• Biodiesel = fatty acid methyl esters• Trans-esterify oils to make them volatile• Projected to be 10% of european diesel in 2015

Lipid metabolismBiofuels are now very fashionable• Biodiesel = fatty acid methyl esters• Trans-esterify oils, used cooking oil, etc• Projected to be 10% of european diesel in 2010

• Also use coconut & other oils directly in diesel engines

Lipid metabolismAlso use coconut & other oils directly in diesel engines• Just need to be sufficiently fluid to reach cylinder

Lipid metabolismAlso use coconut & other oils directly in diesel engines• Just need to be sufficiently fluid to reach cylinder• Add double bonds to fatty acids or make them shorter

Lipid metabolismAlso use coconut & other oils directly in diesel engines• Just need to be sufficiently fluid to reach cylinder• Add double bonds to fatty acids or make them shorter• Problem: shifting from growing food to growing fuel!

Lipid metabolismProblem: shifting from growing food to growing fuel!• Raises price of soybeans & corn

Lipid metabolismProblem: shifting from growing food to growing fuel!• Raises price of soybeans & corn• Cut down forests to grow oil crops in tropics

Lipid metabolismProblem: shifting from growing food to growing fuel!• Raises price of soybeans & corn• Cut down forests to grow oil crops in tropics• Is this environmentally sound?

Lipid metabolismProblem: shifting from growing food to growing fuel!• Raises price of soybeans & corn• Cut down forests to grow oil crops in tropics• Is this environmentally sound?• Depends on real costs of growing, processing and

delivering products

Lipid metabolismIs this environmentally sound?• Depends on real costs of growing, processing and

delivering products• NO! for corn-based ethanol! Use more fuel to grow,

process & deliver it than gain



process & deliver it than gain• Probably yes for cellulosic ethanol: use more of plant,

less fuel to grow, process & harvest




less fuel to grow, process & harvest• Maybe for soy-based biodiesel




less fuel to grow, process & harvest• Maybe for soy-based biodiesel• Maybe for other biodiesel




less fuel to grow, process & harvest• Maybe for soy-based biodiesel• Maybe for other biodiesel• What are the real costs?

Lipid metabolismProblem: are shifting from growing food to growing fuel!• Raises price of soybeans & corn• Cut down forests to grow oil crops in tropics• Is this environmentally sound?

• What are the real costs?• What else could be grown?

Lipid metabolismWhat are the real costs?What else could be grown? Plants that release H2?

Lipid metabolismWhat are the real costs?What else could be grown? Plants that release H2?What else could be done?

Lipid metabolismWhat are the real costs?What else could be grown? Plants that release H2?What else could be done?• Burn crops to make electricity?

Lipid metabolismWhat are the real costs?What else could be grown? Plants that release H2?What else could be done?• Burn crops to make electricity?• EthosGen (Jim Abrams) wants to build an ethanol

production plant in Newport Township


production plant in Newport Township• Army likes their idea, except want them to make

electricity instead!


production plant in Newport Township• Army likes their idea, except want them to make

electricity instead!• Northeast Ethanol and Renewable Resources Ltd.

wants to put a corn ethanol facility in Mayfield

course project = algal lipid production decide which algae to study

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