Changes

The presence of ''Lactobacillus'' can stall or slow yeast fermentation. This is likely a combination of low pH as well as the ability of lactic acid to change the way yeast ferments. Normally, yeast will ferment glucose first before any other sugars that are also available. The presence of lactic acid appears to change the way yeast ferments by allowing them to consume multiple types of sugars regardless of whether or not glucose is presetpresent. See [[Lactic Acid]] for more information. Peyer et al. (2017) observed that growth of US-05 was 82% at a pH of 3.51, and 53% at a pH of 3.17. Fermentation was delayed by 2-4 days (the lower the pH, the longer the start of fermentation was delayed). In a co-fermentation of ''Lactobacillus amylovorus'' and US-05, the initial growth of the ''L. amylovorus'' continued for 3 days while the US-05 was delayed. On day 7, the US-05 recovered and continued growth, and the growth of the ''Lactobacillus'' was slowed starting on day 5. This was due to the increase in ethanol from fermentation, lower pH, and the depletion of nutrients for the ''Lactobacillus''. It is also possible that the yeast benefited from the autolysis of the ''Lactobacillus'', which is speculated to have released nutrients that were made available to the yeast <ref name="Peyer_2017" />.