Evolution and adaptation of XR122N to high solids loading of pretreated pine to produce AJP40. XR122N was inoculated into a 17.5% w/v solids fermentation, and allowed to ferment for 168 hours. 10% v/v aliquots were removed as indicated in the text, and used to inoculate 17.5% w/v solids fermentations. Ethanol was measured every 24 hours, and an additional 2 g/L cdw of XR122N added as indicated. After six full cycles the pattern changed, and ethanol was produced after 24 and 48 hours of fermentation without the addition of more XR122N cells. Cycles 4 and 5 had identical performance to cycles 2 and 3, and are omitted for clarity.