[MUSIC] Susan, thanks so much for the great introduction. I think I have a few questions that our audience will, will be interested in. And and you can help us with those. So, one of the things is you showed this great diversity of cyanobacteria that, that, they grow you know, in the arctic. And they grow in thermal hot springs. How does that diversity help? when, when we think about bio-fuel production or production of anything used in cyanobacteria? >> Whenever you have diversity of either the cell physiology, the ecology, where it lives, what that means is that there are different enzymes there to make different products. Because an organism has to be adapted well to its environment. And also the morphology is going to be different. So a cell that is filamentous is going to be expressing genes that you don't have in, in, well, a strain that's filamentous is going to be, its cells are going to be expressing genes that you don't have in. >> Yeah. >> So the unicellular species. But if you think about it, an organism that lives in, for example, very high salt conditions is going to have enzymes that are, have evolved to work in that environment. And as we start sampling different environments we're also just discovering new genes. So genes that we didn't even know about and that means chemistries and enzymes that we didn't already know about. And so whenever we make a, we talk about how important the diversity is, that's because we know that the diversity of raw material that we can work with to engineer. >> So, genetic diversity as well as physiological diversity. >> Exactly. >> So you talk also about having a model system versus having a production strain. In, in your mind, what are the biggest differences between those two? >> Probably the biggest difference is that the model organisms were chosen in many cases decades ago for particular properties that were of interests to the scientists who were bringing them into the lab and starting to work with them. And decades ago we weren't thinking about how well something grows out in a pond to be useful as a biofuel strain. Very often, the organisms were chosen because they did something that the scientists wanted to study. For example, to spe, differentiate specialized cells to fix nitrogen, or because they were easy to work with genetically and traits, there different traits then aqua culture traits and large scale growth traits. And so if we think about what we want to do now, it's important to find organisms that are going to work really well at production scale and then make models out of those and what we mean by model is a strain that there is that there is enough agreement and enough agreement that goes in to work with that strain and to understand it Well. And if we go back really decades to when people were studying cyanobacteria, every paper was on some different strain. >> Right. >> And so that was great. because the diversity was sampled. But it, there wasn't enough effort to make real progress on any one strain. >> That's right. >> And then the models went the other direction to where we really kind of know a lot about a few strains. And now we say, but wait a minute, those arent the ones that have the properties we want to focus on for biofuels. >> That's right. They're just like agricultural, we'll pick a few cyanobacterial >> Right. >> Strains that we'll grow at very large. >> Exactly. >> So one of the things you talked about was this genetic diversity. So, if we look at a cyanobacteria genome, how big and complex are they and how are we going to introduce genes into the production strains that we want? >> They really vary a lot, so the smallest genomes are about 2 million base pairs, and that's smaller than the genome of E coli which is the most commonly genetically engineered strain. And then there are others that are up around six, eight, or even 10 million base pairs which is a much bigger genome. And one, you find, you can't really say that a bigger genome means this or that except that typically for the strains that have a greater metabolic diversity they are a great more unusual metabolic capabilities, and more tricks that they can do. >> Mm-hm. >> They're going to have bigger genomes. Now in terms of introducing genes, it's not just that if you have a bigger genome to begin with you can introduce more genes. The small organisms can in fact sometimes take very big transfers of pathways, and I think that good examples of that from, from genetic re, genetic history biotechnology history is that E coli, is a, you know reasonably small genome organism and a lot has been done with engineering E coli. >> Right. So, I know in terrestrial agriculture one of the big concerns, that I mean the things that farmers fight all the time are crop protection. How do I keep pests and pathogens from eating my crop or fungus from taking it down. Will that be the same in a biofield crop of cyanobacteria? >> Oh absolutely, so anything that an organism is making that we find valuable. It's probably going to have a good source of carbon in it. And carbon is what organisms use as the skeleton of everything that they need for their cells. Which means that if there's something out there that is alive something else is going to eat it. >> That so. >> It pretty much comes down to that. And so we do have to worry about invading organisms of a couple of sorts. Either that will compete for nutrients and compete for resources, or that will actually consume and otherwise kill the crop. >> So weeds versus predators or pathogens. >> Exactly. And there are many of both kinds that are out there constantly moving around and settling anywhere including in the ponds. >> So what, are some of, some of the strategies that your group is, is thinking about, in, in order to get crop protection [UNKNOWN]. >> Well for different kinds of, of algal crops there are different kind of characteristically notorious ponds, and for sign of bacteria if you talk to people that are raising these ponds they'll tell you that amoebae are a big problem. Now, there are lots of different kinds of amoebae, but knowing that amoebae problem, one of the things that we've done is, along with our collaborators at the Scripps Institution of Oceanography, we've been identifying we've been identifying amoebae that specifically eat the cyanobacteria that we use as a model, for which we do have a lot of genetic tools. And once we had that predictor prey system set up we could, we could screen an entire library of mutants which means a collection of mutants were each one is missing a different gene and we were able to find that we could knock out a particular pathway that affects the cell surface and the meeting no longer then this particular amoeba anyway no longer eats our bacterium. So that, that really gave us a first clue, of one of the things that we can do to make cells resistant to amoeba put some kind, some kind of a mask on them. >> Mm-hm. >> So they no longer look so tasty and there are probably many other ways but, we, once we have the question we can go in and ask it and. >> So it sounds though, that crop protection in algal biofuels would be similar. >> Right. >> You know, not identical, but similar to the strategies that we've employed for terrestrial crops. >> Right. Which is, you have to identify the pest that you're concerned about and try to find a solution that works with that pest. And then you have to go back and ask, well, how general is it? And does this protect from other pests? Or do we need some other strategy for other pests? >> Okay, I know one of the other concerns in, in, any biofuel, in any crop. And especially if we're going to use crops like, like cyanobacterial for fuels. Are both the water utilization as well as the nutrient utilization. Now you mentioned that nitrogen can be fixed by these, but what are some of the other nutrients and, and what are some of the other strategies that we might use to, to make sure that we're efficiently using those? >> Well, phosphorus is another one that's quite important in biological systems and phosphorus is an issue really for all agriculture and will certainly be an issue for algal crops. And recycling the nutrients is an important avenue going forward, to make sure that the phosphorous in the water gets re-utilized, that any of the biological material, the spent biological material that the that the fuel molecules have been removed from, that, that gets put back into the system so that we can recycle those nutrients. >> And in the nitrogen-fixing then, how is it that cyanobacteria can do this where most terrestrial plants and certainly eukaryotic green algae cannot? >> There is, cyanobacteria aren't the only organisms that can fix nitrogen, but most organisms don't and the ones that we do know of are prokaryotic, although sometimes they live in symbiosis with eukaryotes. >> Right. >> And nitrogen fixation requires really a lot of genes to make a lot of, not only a lot of enzymes, but to specialize the cells to be able to keep the oxygen tension low. So the enzyme that's used to fix nitrogen in the air into ammonia is very sensitive to oxygen. >> Right. >> And one of the things that we see in these species that can, is that they have a number of different strategies for having their, their, their nitrogenous enzyme active in some sort of an intracellular environment where the oxygen tension's very low. >> Right. Hence, the specialized cells that you showed in that one. >> Exactly. >> Okay so, you know you, we, we talked about the potential for biofuels. You showed in one of your early slides that cyanobacteria can be eaten, actually, as a food. So obviously we can make food and fuel out of, out of cyanobacteria. What are the other potentials that you see in this that sort of excite you about the future and, and where the field may go? >> Well, I think that it's very important that we learn to replace petroleum as a source for all kinds of chemicals. So it's not only a matter of fue, foo, excuse me fuel or a food, or or medicines but also just a lot of the every day things that we use that are currently made of plastics and so I think as a source of the carbon skeletons that can be used for a lot of the materials and the structures that we need in our every day life. The ability to use algae both cyanobacteria and eukaryotic algae as a source of the building blocks of those materials would be very important. >> Okay, great. Well thanks very much for the introduction to cyanobacteria and best of luck to your research. >> Thank you.
