 I'm Kevin Verstraepen. I'm a geneticist and a microbiologist working at the University of Lurven and VIB in Belgium. I'm here with Professor Kevin. We are shortly after him finishing his sessions. So everything is fresh in our minds and I'm very interested to learn how did your session go? What was the topic? I was in the session of metabolism, which was interesting. It's not a session I'm often in, but it was fantastic. We had a mix of people talking about metabolic models and then people like me may be studying more the molecular aspects of it. And you gave a talk right in that session as well? Yeah, I was talking about the lack phase. So this phase that I think all microbiologists know, right? Sort of an adaptation phase when microbes switch between one environment to the other. They stop growing and they have to adapt. And we've been studying one specific lack phase in yeast, in saccharomyces, where they transition from glucose to another carbon source, like maltose. And we've been trying to figure out what happens in that phase and specifically what determines the length of this adaptation phase of the lack phase. Yes, very interesting because I know for me when I was growing bacteria, I was more interested on the exponential phase just to see how long do I have to wait until my bacteria reach a certain CFU. But it's very interesting that you are investigating the lack phase. So how did that come about? Well, it's a funny story and it's a true story. This happened, we started looking at this more than 10 years ago when my lab was back in the US. There was a brewer who called me asking me why his yeast had such trouble starting to grow on maltose, which is the main sugar in beer medium, after he pregrew the yeast on glucose, which he did in the lab. And then he always saw a long lack phase. He didn't know the word lack phase. And that really triggered that sparked this interest. And there just happened to be one grad student who walked in my office literally the same week looking for a project that was somewhat a bit beer related. And so we put it together and he started working on this. This is Aaron Yu. And yeah, so it took us 10 years and we're still finding out new things. Yeah. And so what does your research show so far about the lack phase? Is it something that is conserved? Is it variable? So yeah, all of those things. So the lack phase is always there when these microbes need to change. But it is extremely variable. So different yeast strains, so genetically different yeast have very different lack phases. So some can adapt very quickly and resume growth quickly and others take much longer. But even more interestingly, you have genetically identical cells, a whole population that are sitting in the same environment. And you have to go to make the switch and some take ages and others do it in a matter of two hours. And others even never make it. They never make the switch, which you don't see at the population level. Because if you're looking at your tubes, yeah, you see that growth slows down. And then after a few hours, it picks up again, the classic sort of bimodal behavior. But when you look at the individual cells, you see that actually many cells don't switch, which didn't make any sense to us. And then a few start growing. And of course, they multiply and then you get exponential growth anyway. Yeah, interesting. And for example, this variable, let's say lack phase, does it have an effect on the overall fitness? So yeah, that's another really good question. You would you would think that being fast is always better, right? Because you're in an environment, your glucose, your favorite sugar is run out, and you need to adapt to the new environment, you better face up and start growing. And in the meantime, your competitors might already start growing on the new source. So it makes sense to have a short lack phase. So why do some cells or strains have a long lack phase? It turns out, and that is something we're, we haven't really published yet, that the cells with a long lack phase actually have a benefit in the constant environment, they grow a little bit quicker, probably because they're fully committed to that environment, have optimized their metabolism, but then it takes them longer to adapt to the new one. Yeah. And my final question is towards more like the application side. So you know, your research shows stuff about the lack phase and then how would that be helpful in the application, for example, in the beer brewing? Yeah, that sort of ties back then to the whole beginning of the story, right? We had this brewer coming with this question and that never left our mind. So we just received a proof of concept grant from the ERC to investigate exactly the application side. So can we now use what we've learned and we've identified pieces of DNA and new gene that influences the lack phase? Can we use this to make strains that are more efficient at transitioning and therefore maybe more efficient in industrial practices like beer brewing, but not just beer brewing? So that's exactly something that we're figuring out at this very moment now. So I was made aware that you were also involved in an online course called Science of Brewing, right? Yeah, that's a real fun one. It's a free online course about the science of brewing, a large part of its microbiology because it's people in my lab who made the course and myself. And it's a fantastic course to recommend to anyone, to maybe your parents or friends who wonder what you're really doing and why they should care, because it starts from a quite basic level and it introduces them to many of the key aspects of biochemistry and microbiology and even a bit of engineering, but then always using the topic of beer, which is usually quite interesting to many of us, right? Even people who don't care about microbiology so much. Yeah, everyone can relate, right? Exactly. So in the two years that we've headed out now, more than 16,000 people took it and the reactions have been quite overwhelmingly positive. So you can Google it. It's on the Atex platform, quite a well-known platform for free courses. So yeah, please go and take it. I think it's a fun course and you learn a lot about beer and like I said, if you don't know microbiology, you even learn something about microbiology. Great, very interesting. And just to enter the interview, I just wanted to ask you about this conference, I guess for most of us, it's our first in-person conference for quite a while. How are you finding the overall experience of being back to having all those people around you networking? Yeah, it's one of those things where you only realize how important it is when you don't have it anymore. To be honest, before the pandemic, like many of us, I guess, I was getting maybe fed up with too many conferences. I said, travel again, leave my family almost every week. And then it was quite a relief, maybe the first lockdown. But then after in Belgium, we're now at, well, we went through three and I haven't traveled for a year and a half, no live conferences. So it's so fantastic then to come to a conference again and talk face to face to people. It is much nicer than behind the screen. Yeah, I agree. So yeah, that's all I had for you today. Thanks so much for your time and enjoy the rest of the conference.