suregork
Well-Known Member
So this is not super relevant to homebrewers, but I thought it might at least interest some of you. This is related to diastatic brewing yeast (i.e. the yeast formerly known as Saccharomyces diastaticus). About a year ago I set out to elucidate the reasons behind why some strains carrying the STA1 gene cause super-attenuation, while others are more benign. I'm now very excited to share our results! Below I’ll mention the main results.
First of all, here is a link to a pre-print (manuscript that has been submitted to a scientific journal for peer-review) with all the results: https://www.biorxiv.org/content/10.1101/654681v1
I’ve also summarized the paper in my blog for those interested (a bit more 'user friendly' text): http://beer.suregork.com/?p=4068
- The first main result is probably of most use to the brewing community. The variable diastatic ability in STA1+ strains is determined by a 1162 bp deletion in the STA1 promoter. Strains with the deletion are not very diastatic. You can use our newly designed PCR primers to differentiate between STA1+ strains with and without the deletion.
- The second result was that STA1 is not linked to wild yeast, rather it appears to be prevalent only in ‘Beer 2’/’Mosaic Beer’ strains, and surprisingly the ‘French Guiana, human’ strains. STA1 presumably gives a fitness advantage in starch-rich environments (e.g. beer).
- The third major result was that STA1 enables efficient maltotriose consumption in STA1+ strains. This appears to be the unknown mechanism that has enabled efficient maltotriose use in the ‘Beer 2’ strains (which otherwise have a non-functional AGT1/MAL11 transporter). STA1 therefore seems to be an alternative evolutionary route (‘domestication signature’) to enable efficient utilization of the sugars present in wort.
Let me know if you have any questions or feedback, I’d be happy to help!
First of all, here is a link to a pre-print (manuscript that has been submitted to a scientific journal for peer-review) with all the results: https://www.biorxiv.org/content/10.1101/654681v1
I’ve also summarized the paper in my blog for those interested (a bit more 'user friendly' text): http://beer.suregork.com/?p=4068
- The first main result is probably of most use to the brewing community. The variable diastatic ability in STA1+ strains is determined by a 1162 bp deletion in the STA1 promoter. Strains with the deletion are not very diastatic. You can use our newly designed PCR primers to differentiate between STA1+ strains with and without the deletion.
- The second result was that STA1 is not linked to wild yeast, rather it appears to be prevalent only in ‘Beer 2’/’Mosaic Beer’ strains, and surprisingly the ‘French Guiana, human’ strains. STA1 presumably gives a fitness advantage in starch-rich environments (e.g. beer).
- The third major result was that STA1 enables efficient maltotriose consumption in STA1+ strains. This appears to be the unknown mechanism that has enabled efficient maltotriose use in the ‘Beer 2’ strains (which otherwise have a non-functional AGT1/MAL11 transporter). STA1 therefore seems to be an alternative evolutionary route (‘domestication signature’) to enable efficient utilization of the sugars present in wort.
Let me know if you have any questions or feedback, I’d be happy to help!
