Department of Paper and Bioprocess Engineering, SUNY ESF, 1 Forestry Drive, Syracuse, NY 13210, USA.
Appl Biochem Biotechnol. 2012 Sep;168(1):29-36. doi: 10.1007/s12010-011-9285-0. Epub 2011 May 21.
Concentrated dilute acid hydrolysate was obtained from hot water extracts of Acer saccharum (sugar maple) and was fermented to ethanol by Pichia stipitis in a 1.3-L-benchtop bioreactor. The conditions under which the highest ethanol yield was achieved were when the air flow rate was set to 100 cm(3) and the agitation rate was set to 150 rpm resulting in an overall mass transfer coefficient (K(L)a) of 0.108 min(-1). A maximum ethanol concentration of 29.7 g/L was achieved after 120 h of fermentation; however, after 90 h of fermentation, the ethanol concentration was only slightly lower at 29.1 g/L with a yield of 0.39 g ethanol per gram of sugar consumed. Using the same air flow rate and adjusting the agitation rate resulted in lower ethanol yields of 0.25 g/g at 50 rpm and 0.30 g/g at 300 rpm. The time it takes to reach the maximum ethanol concentration was also affected by the agitation rate. The ethanol concentration continued to increase even after 130 h of fermentation when the agitation rate was set at 50 rpm, whereas the maximum ethanol concentration was reached after only 68.5 h at 300 rpm.
浓缩稀酸水解物是从糖枫（ Acer saccharum ）的热水提取物中获得的，并通过毕赤酵母（ Pichia stipitis ）在 1.3-L 台式生物反应器中发酵为乙醇。当空气流速设定为 100 cm³，搅拌速度设定为 150 rpm 时，可以获得最高乙醇产率的条件，这导致总体传质系数（K（L）a）为 0.108 min⁻¹。在发酵 120 h 后，达到了 29.7 g/L 的最大乙醇浓度；然而，在 90 h 的发酵后，乙醇浓度仅略低，为 29.1 g/L，消耗每克糖的乙醇产率为 0.39 g。使用相同的空气流速并调整搅拌速度导致较低的乙醇产率，在 50 rpm 时为 0.25 g/g，在 300 rpm 时为 0.30 g/g。达到最大乙醇浓度所需的时间也受到搅拌速度的影响。当搅拌速度设定为 50 rpm 时，即使在发酵 130 h 后，乙醇浓度仍继续增加，而在 300 rpm 时，仅在 68.5 h 后就达到了最大乙醇浓度。
