Bio fuels, bovine food and bacterial machines

By Liz Franson

Energy crisis and biofuelsThe new interest in biofuels is driven by

increased energy demand and environmental and economic instability of fossil fuels

Biofuels are alternative fuels that derive energy from carbon fixated by living organisms such as plants and photosynthetic bacteria.

Corn, sugar cane to ethanolMicrobe fatty acids to biodiesel

Cellulosic ethanol Ethanol is commonly used as a gasoline additive Ethanol is fermented using biomass from sugar rich crops and more recently plants with high cellulose content such as switch grassCellulose is the most abundant form of organic carbon less energy to produce,Net use of carbonWould not compete with food

Synthetic bio improvementsPretreated then subjected to cellulose hydrolyzing

enzymesPlants with more celluloseBroken up ligninPretreatment with ionic liquidsDelete inhibitors

Pgaso (not pagaso) Promoter-based Gene Assembly and Simultaneous OverexpressionEngineer yeast to both break down cellulose and

ferment sugarUsed ky3 yeast inserted 5 cassette genes coding

for cellulases Multiple genes in single system but kept individual

promoters

Pgaso cont.

Promoter gene terminator fragUses homologues recombination

results

62.5% transformed correctlyNew kr5 strain preformed 63 to 90% capacity of

commercial enzymes (novozyme, celluclast)for cellulose degradation

93% conversion of cellobiase to ethanol74% conversion of beta glycan (nc could not grow)Also heat and toxin resistant

Let them eat grass

How bacteria, cows and synthetic biology can help solve world hunger

purpose

To provide a potential solution for hunger and povertynumbers. It is estimated that between 870 million

and 1.02 billion , are victims of hunger and make up 15% of the people in developing nations.

Nearly half of the deaths of children are due to hunger related causes.

demand for food is expected to increase by nearly 50% crop yields in many poor and developing countries is expected to plummet by more than 25%.

bacteria cows and synthetic bioWhat If humans could eat trees and grassCows horses and sheep Humans house millionsOf bacteria in there body a bacteria that could Break down cellulose in plants and live in humans

Competing techMajor solution currently adopted is agricultural

developmentDesign would be cooperative not competitiveZhang of the Virginia Polytechnic Institute Converts cellulose in labCan convert 1/3 of celluloseEconomic viability questionable

designUse E coli hostCellulose degradationBreak down when cellulose is main substrate

presentDon’t break down if glucose is present or there is

no celluloseBreak beta bondscellulosome

celluloseCellulose vs. glucose

cellulosomeMore efficientBetter equipped for digestive track

cellulosome genes

Cyspin inhibits binding

Gene regulationcyspin

Gene is repressed in absence of glucose

Transcribed in presence

T. clostridiumAbsence of cellulose

gene inactiveCellulose activates

sigma based rna polymerase

Expected results

Expected resultsInevitably there will be some inefficiency Sometimes glucose or cellulose may fail to bind

even when presentThe cell may be on low when should be offCellulosomes should still be efficient enough to

have a positive net glucose for the host More glucose means energy means better survival

advantagesFew have considered cellulose as a source of fuel

for humansAdvantages over lab cellulaseEasy one time distributionLow maintenance Could be utilized by those who need it mostRevolutionize human survival

Potential problemsEfficiency of cellulose degradation Impact of environment Impact on other gut symbiontsHas never been attemptedRelatively harmless Anaerobic little harm to environmentuse basic safety precautions rewards outweigh risks

testingMany types of cellulases Designer cellulosomesWould replicate intestinal conditions to ensure safetyMost testing done within host Compare energy transfer between hosts Improve efficiency of hydrolizationCould be applied to biofuels as well Test

subject

The end