Changes

Colomer et al. (2020) was the first to examine the effects of ''Brettanomyces'' on hops during fermentation. The researchers selected 4 strains of ''B. bruxellensis'' and 1 strain of ''B. anomalus'' that had the genetic markers for producing beta-glucosidase enzyme, and fermented them as a primary fermenter in a non-dry hopped beer, and also performed a second experiment where they inoculated the ''Brettanomyces'' strains in a dry hopped beer that was first fermented with ''S. cerevisiae''. Monoterpene alcohols were measured before and after inoculation with the 5 strains of ''Brettanomyces''. In both beers, they found a decrease in geraniol and a rise in beta-citronellol after the inoculation with ''Brettanomyces''. Beta-citranellol reached a level of 31.5 μg/L with one of the strains, which is a much higher level of beta-citronellol than anything that has been reported with ''S. cerevisiae'', suggesting that some strains of ''Brettanomyces'' might be better at converting monoterpenes from hops than ''Saccharomyces''. See [https://onlinelibrary.wiley.com/doi/full/10.1002/jib.610 Figure 5] in the open access study. Interestingly, the strains with the highest beta-glucosidase activity produced the lowest amount of beta-citranellol, indicating that there is no link between beta-glucosidase activity in ''Brettanomyces'' and hop biotransformation. This might be due to the fact that most of the beta-glucosidase enzyme is produced within the cell and is not released outside of it. The researchers hypothesized that this conversion could be due to two proteins referred to as BbHye2 and BbHye3 that can be present in ''Brettanomyces'' metabolism <ref>[https://onlinelibrary.wiley.com/doi/full/10.1002/jib.610 Biotransformation of hop derived compounds by Brettanomyces yeast strains. Marc Serra Colomer, Birgitte Funch, Natalia Solodovnikova, Timothy John Hobley, Jochen Förster. 2020. DOI: https://doi.org/10.1002/jib.610.]</ref>.

===Nitrogen Metabolism===