1 00:00:00,120 --> 00:00:03,041 So we were recently at the Faculty of Bioscience Engineering. 2 00:00:03,141 --> 00:00:04,773 What's your connection to that place? 3 00:00:04,873 --> 00:00:07,002 Well, that’s simple; it’s my faculty! 4 00:00:07,122 --> 00:00:08,803 where I was also studying yeast. 5 00:00:10,063 --> 00:00:14,425 Before that I actually did my PhD in that building of Bioscience Engineering. 6 00:00:14,525 --> 00:00:16,806 So I was in the brewing school, doing my PhD. 7 00:00:16,906 --> 00:00:20,107 That's where I got hooked on yeast and beer, I guess. 8 00:00:20,207 --> 00:00:23,549 So I found this in your office. Can you tell us something more about it? 9 00:00:23,649 --> 00:00:26,596 That's my lunch you have there! Give it back! 10 00:00:26,710 --> 00:00:32,192 This is the official University beer actually. So, KU Leuven has a beer. 11 00:00:32,292 --> 00:00:35,173 You can actually buy this in the University shop downtown. 12 00:00:35,713 --> 00:00:40,072 So this is where we keep all the yeasts. Our treasure. 13 00:00:41,040 --> 00:00:43,800 There's a lot of them, as you can see. All these boxes. 14 00:00:44,300 --> 00:00:46,500 And each box contains a hundred different ones. 15 00:00:47,300 --> 00:00:51,934 So every little tube is a different yeast and so we have breweries from 16 00:00:52,034 --> 00:00:55,700 all across the world that give us their yeast and we keep it for them. 17 00:00:55,800 --> 00:00:58,700 So if the brewery burns down, we can resend their yeast 18 00:00:58,800 --> 00:00:59,900 and they can still make their beers. 19 00:01:00,000 --> 00:01:02,800 But why is it so important? If the brewery burns down, 20 00:01:02,900 --> 00:01:05,700 why can't they generate different kinds of yeast? 21 00:01:05,900 --> 00:01:10,500 Ah, because every yeast is different. 22 00:01:11,000 --> 00:01:12,900 So every beer is made with a different yeast. 23 00:01:13,000 --> 00:01:16,644 So one of the things that makes a beer distinct 24 00:01:16,744 --> 00:01:19,387 and differ from each other is the different yeast they use. 25 00:01:19,487 --> 00:01:21,617 This has been going on for more than five years now. 26 00:01:21,717 --> 00:01:25,400 What we have here are six reactors in the back; 27 00:01:25,500 --> 00:01:27,920 you can hardly see them with all the cables and bottles. 28 00:01:28,020 --> 00:01:30,500 There are six reactors that have been going for five years. 29 00:01:30,600 --> 00:01:35,900 There's different yeast in them and so these bottles here contain food for the yeast. 30 00:01:36,000 --> 00:01:40,700 But we also pour alcohol in them. And so they're continuously getting more food, 31 00:01:40,800 --> 00:01:44,220 slowly, but continuously. And also we pump the same volume out of the bottle. 32 00:01:44,320 --> 00:01:45,980 So it's a continuous culture. 33 00:01:46,212 --> 00:01:48,827 And so the yeasts are dividing and growing in there. 34 00:01:49,127 --> 00:01:53,660 And we're always - slowly, every month or so - we're increasing the alcohol level 35 00:01:53,760 --> 00:01:55,782 that we put in these bottles. 36 00:01:55,882 --> 00:01:59,619 So these yeasts are exposed to more and more alcohol. 37 00:01:59,720 --> 00:02:02,000 It's like we give them more and more beers to drink, in a way. 38 00:02:02,420 --> 00:02:04,380 And what we hope and what they're doing is, 39 00:02:04,480 --> 00:02:09,180 they're genetically adapting to higher alcohol levels. So their DNA is changing 40 00:02:09,493 --> 00:02:13,808 and slowly but surely, through Darwin pretty much at work, 41 00:02:14,137 --> 00:02:16,560 their DNA is changing to make them more resistant 42 00:02:16,660 --> 00:02:19,160 to higher alcohol levels, because alcohol is toxic. 43 00:02:19,260 --> 00:02:21,200 Not only for humans but also for yeast. 44 00:02:21,300 --> 00:02:24,098 But how is it useful in chocolate and biofuels? 45 00:02:24,770 --> 00:02:27,742 Well, biofuels is kind of obvious in a sense that 46 00:02:28,586 --> 00:02:34,402 bioethanol, so alcohol, is increasingly important as an additive to fuels. 47 00:02:34,502 --> 00:02:40,290 So that's made by yeast cells and we just try to create yeast cells that are making more alcohol. 48 00:02:42,105 --> 00:02:43,940 Chocolate is a different story. 49 00:02:44,040 --> 00:02:47,878 Chocolate is also fermented, so microbes play a role in chocolate. 50 00:02:48,136 --> 00:02:53,438 Chocolate grows on cacao trees and these trees have pods 51 00:02:53,538 --> 00:02:55,168 - a bit like coconuts, this size. 52 00:02:55,318 --> 00:02:58,625 And inside these pods you have about 30 to 50 beans. 53 00:02:58,983 --> 00:03:00,955 But they're surrounded by a gooey pulp. 54 00:03:01,270 --> 00:03:05,885 So when these pods are harvested, the farmers cut them off with their machetes 55 00:03:06,072 --> 00:03:10,625 and they cut open the pods and they spill the beans onto this big heap on the soil, 56 00:03:10,725 --> 00:03:12,044 right there on the farms. 57 00:03:13,489 --> 00:03:16,890 And then you have microbes falling in and they eat away the pulp 58 00:03:16,990 --> 00:03:19,433 that surrounds the beans 59 00:03:19,548 --> 00:03:25,108 and so in about a week or so the pulp disappears, liquefies and disappears. 60 00:03:25,651 --> 00:03:30,581 It's a spontaneous process so you just have the microbes that are present there at the farms that do this. 61 00:03:31,510 --> 00:03:36,069 But it's not always ideal. Sometimes the wrong microbes get into the beans 62 00:03:36,169 --> 00:03:38,726 and you get chocolate that doesn't taste very well. 63 00:03:38,999 --> 00:03:41,723 So one of the things we're doing is to try to make microbes that 64 00:03:41,823 --> 00:03:45,200 are doing a better job at fermenting these beans. 65 00:03:46,000 --> 00:03:47,680 What are your favorite beers personally? 66 00:03:47,680 --> 00:03:50,140 Oh, my favorite beers? I like the Trappist beers. 67 00:03:50,240 --> 00:03:53,100 I think they're really good so I'm very proud of them. 68 00:03:53,200 --> 00:03:56,260 It's really heritage, right. You have these monks making beer 69 00:03:56,360 --> 00:03:58,260 and we actually do a lot of work for them. 70 00:03:58,360 --> 00:04:02,193 I'm also very proud of the the largest brewery we have right here in town. 71 00:04:02,293 --> 00:04:05,780 AB IMBEV, right? The largest brewing concern in the world. 72 00:04:05,880 --> 00:04:09,682 So that's something to be really proud of if you're working here in Leuven. 73 00:04:09,853 --> 00:04:12,640 And that's a really fun company to have as a neighbour as well. 74 00:04:13,469 --> 00:04:17,199 I like Duvel, which is again a Belgian classic. 75 00:04:17,299 --> 00:04:20,072 But to be honest, you know, you have to taste all the different beers, right? 76 00:04:20,172 --> 00:04:21,429 There's a good beer for every occasion. 77 00:04:21,529 --> 00:04:23,180 So I don't think we have many bad beers. 78 00:04:23,280 --> 00:04:29,575 It's about drinking what you like at a specific moment. At a specific time during the day. 79 00:04:29,675 --> 00:04:33,977 Yes, perfect. There's a beer for every time of the day.