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In a previous study by Jarosz et al. (2014), it was observed that only certain bacteria species had the effect of inducing <nowiki>[</nowiki>GAR<sup>+</sup><nowiki>]</nowiki> in some strains of yeast. These bacteria included ''P. damnosus'', ''Lactobacillus kunkeei'', and species from genres ''Staphylococcus'', ''Micrococcus'', ''Bacillus'', ''Listeria'', ''Paenibacillus'', ''Gluconobacter'', ''Sinorhizobium'', ''Escherichia'', ''Serriatia''. In this study, ''L. brevis'', ''L. hilgardii'', ''L. plantarum'' did not appear to induce <nowiki>[</nowiki>GAR<sup>+</sup><nowiki>]</nowiki> in yeast <ref name="cross-kingdom" />. At the time of this study, it was not understood that lactic acid was an inducer of <nowiki>[</nowiki>GAR<sup>+</sup><nowiki>]</nowiki>. Additionally, the method they used to discover this was simply to streak bacteria next to yeast on a plate, and see if it grew on a medium that would show whether or not they bypassed glucose repression. Therefore, it is possible that not enough lactic acid was produced, or that they didn't give the bacteria enough time to have an effect on the yeast. More work would need to be done to show that indeed all lactic acid bacteria that produce lactic acid have this effect on yeast even though this does seem to actually be the case <ref name="preiss">[https://www.facebook.com/groups/MilkTheFunk/?comment_tracking=%7B%22tn%22%3A%22R4%22%7D Conversation with Richard Preiss on MTF. 12/7/2016.]</ref>.
In beer, this might explain other observations as well. For example, Yakobson reported higher attenuation with some strains of ''Brettanomyces bruxellensis'' (WLP650, BSI Drie, CMY001, and WY5526) and one strain of ''B. anomalus'' (WY5151) had a higher attenuation with higher concentrations of lactic acid <ref>[http://brettanomycesproject.com/dissertation/pure-culture-fermentation/impact-of-initial-concentration-of-lactic-acid/ "The Brettanomyces Project". Chad Yakobson. 2011. Retrieved 12/7/2016.]</ref>. In mixed fermentations of beers such as lambic and American sour ales, attenuation is often slower, but eventually higher than when lactic acid are not present. Some strains of ''S. cerevisiae'' are more tolerant of acidic conditions than others. Although this might answer some questions, mixed fermentation are is a complex thing with many other variables and more work needs to be done to identify whether all or just some strains of yeast/bacteria have the effect of inducing <nowiki>[</nowiki>GAR<sup>+</sup><nowiki>]</nowiki>, and how that might effect the fermentation profile of various types of beers <ref name="preiss"/>.
==See Also==