Bio fuels, bovine food and bacterial machines

Bio fuels, bovine food and bacterial machines By Liz Franson

Energy crisis and biofuels • The 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 ethanol • Microbe 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 grass Cellulose is the most abundant form of organic carbon less energy to produce, Net use of carbon Would not compete with food

Synthetic bio improvements • Pretreated then subjected to cellulose hydrolyzing enzymes • Plants with more cellulose • Broken up lignin • Pretreatment with ionic liquids • Delete inhibitors

Pgaso (not pagaso) • Promoter-based Gene Assembly and Simultaneous Overexpression • Engineer yeast to both break down cellulose and ferment sugar • Used ky3 yeast inserted 5 cassette genes coding for cellulases • Multiple genes in single system but kept individual promoters

Pgaso cont. • Promoter gene terminator frag • Uses homologues recombination

results • 62.5% transformed correctly • New kr5 strain preformed 63 to 90% capacity of commercial enzymes (novozyme, celluclast)for cellulose degradation • 93% conversion of cellobiase to ethanol • 74% 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 poverty • numbers. 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 bio • What If humans could eat trees and grass • Cows horses and sheep • Humans house millions Of bacteria in there body a bacteria that could Break down cellulose in plants and live in humans

Competing tech • Major solution currently adopted is agricultural development • Design would be cooperative not competitive • Zhang of the Virginia Polytechnic Institute • Converts cellulose in lab • Can convert 1/3 of cellulose • Economic viability questionable

design • Use E coli host • Cellulose degradation • Break down when cellulose is main substrate present • Don’t break down if glucose is present or there is no cellulose • Break beta bonds • cellulosome

cellulose • Cellulose vs. glucose

cellulosome • More efficient • Better equipped for digestive track

cellulosome genes Cyspin inhibits binding

Gene regulation cyspin T. clostridium Absence of cellulose gene inactive Cellulose activates sigma based rna polymerase • Gene is repressed in absence of glucose • Transcribed in presence

Expected results

Expected results • Inevitably there will be some inefficiency • Sometimes glucose or cellulose may fail to bind even when present • The cell may be on low when should be off • Cellulosomes should still be efficient enough to have a positive net glucose for the host • More glucose means energy means better survival

advantages • Few have considered cellulose as a source of fuel for humans • Advantages over lab cellulase • Easy one time distribution • Low maintenance • Could be utilized by those who need it most • Revolutionize human survival

Potential problems • Efficiency of cellulose degradation • Impact of environment • Impact on other gut symbionts • Has never been attempted • Relatively harmless • Anaerobic little harm to environment • use basic safety precautions • rewards outweigh risks

testing • Many types of cellulases • Designer cellulosomes • Would replicate intestinal • conditions to ensure safety • Most testing done within host • Compare energy transfer between hosts • Improve efficiency of hydrolization • Could be applied to biofuels as well Test subject

The end

Bio fuels, bovine food and bacterial machines