1. What is the source of your enzymes for biofuel generation?
Environmental microbes are an untapped resource for enzymes that can degrade cellulose and lignin structures. By identifying many different types of cellulases and ligninases, we can engineer better and more efficient enzymes that can increase the speed and most importantly, the specificity, of the biofuel conversion process.
2. How do you go about finding these enzymes?
Our screening platform is designed to rapidly discover clones that produce natural products, such as the enzymes that degrade lignin and cellulose. The key aspect of this screening work is to exploit natural environments such as biomass compost and the gut of the wood-eating catfish from South America, for example, that are naturally a rich source for wood and plant-degrading microorganisms. The vast majority, (over 99% of the microbes in natural environments) cannot be easily cultured in a laboratory, so our genomic technology provides a way to access these previously untapped reservoirs of enzyme diversity.
3. Are you just adding enzymes to your biomass?
No, that would be inefficient since those enzymes would have a fairly short half-life. A better approach is to engineer a microbe to express your recombinant enzyme and allow that engineered microbe to grow and express the enzyme in the biomass “slurry”. In this way the microbe will grow rapidly and will constantly replenish the amount of active enzyme in the biomass conversion process.
4. Could your genetically engineered microbe escape into the environment?
The bioreactor that the engineered microbes will be growing in is a highly selective environment due to its high temperature (and likely low pH), so that survival in the surrounding natural environment would be highly unlikely. And furthermore, there would be no danger to living plants since the enzymes would be engineered to work on processed and acidified plant tissues.
5. How do you separate the hydrocarbons you want from the rest of the slurry?
A distillation process would be used, first heat would be applied to evaporate any volatile hydrocarbons and these would be collected and processed according to standard distillation procedures.
6. How can you be sure that you will find the novel enzymes that will generate short-chain hydrocarbons?
The capacity of microorganisms to degrade naturally occurring compounds, such as cellulose and lignin, has already been demonstrated using conventional microbiologic approaches. Novel cellulases have already been discovered, and using cutting-edge genomics approaches, we will utilize more refined genetic techniques for acquiring and expressing the cloned enzymes.
7. What are the kinds of biomass that you will degrade?
We will focus primarily on pine tree residues and agricultural biomass from peanut plants initially.
8. What kind of efficiency can you expect from this process?
Our very achievable goal is to improve the overall efficiency of the biofuel conversion process. The enzyme biocatalysts discovered in this process will be of benefit to many other researchers in the biofuel industry in the United States.
9. What is the probability for success?
Every environment that we sample will have enzymes designed by “nature” to degrade plant cellulose and lignin. There is no doubt that such enzymes can be used to degrade naturally occurring plant biomass, and can be engineered for even greater efficiency and thermal stability. The question will be how much greater efficiency can be achieved?
10. Why would your enzymes work better than the ones that currently exist?
By engineering a microbial enzyme for biofuel production we can tailor the enzyme for a specific biomass conversion process, with a unique microbial “cocktail” designed especially for each different kind of biomass. In other words, for every kind of biomass targeted for biofuel conversion we will develop a unique microbial enzyme factory to degrade that biomass with exquisite specificity and efficiency.
11. Would your engineered microbe survive the extreme oxidation needed to break apart the lignin structure?
We would select our microbial host by processing each biomass type for maximum degradation efficiency, using physical and inexpensive chemical additives. The microbial host (to receive the engineered enzyme) would be selected from this very selective environment, and chosen also on the basis of its ability to produce copious amounts of enzyme.
12. Isn’t this a big “fishing expedition”?
Is dipping your net into an aquaculture pond considered fishing? The risks in this project are minimal, since we are working with naturally occurring enzymes that are present in many diverse microbes – but we truly have little idea how diverse these enzymes are in nature, and if we don’t harness their power for this biofuel process, some other country will!