CICECO, Departamento de Química, Universidade de Aveiro, Campus Universitário de Santiago, P-3810-193 Aveiro, Portugal.
Bioresour Technol. 2010 Apr;101(8):2755-61. doi: 10.1016/j.biortech.2009.11.092. Epub 2009 Dec 31.
The spent liquor from acidic sulphite pulping of Eucalyptus globulus (HSSL) is the side product from sulphite pulp production and besides sulphonated lignin contains sugars from degraded hemicelluloses, mainly pentoses. Pichia stipitis fermentation of these sugars for bioethanol production was the primary goal of this work. The increasing of HSSL proportion in fermentation media affected negatively the ethanol yield. Thus with 20% of HSSL (v/v) attained maximum ethanol yield was 0.15 g of ethanol by g of sugar consumed (g(e) g(s)(-1)) and with 60% (v/v) only 0.08 g(e) g(s)(-1). Biological removal of acetic acid from HSSL improved fermentation though the complete removal of acetic acid and polyphenolics (including sulphonated species) by treatment with ion-exchange resins was required for highly successful bioethanol production. Accordingly, the fermentative metabolic pathway of P. stipitis has been promoted allowing fair ethanol productivity and yield (Yp/s = 0.49 g(e) g(s)(-1)) at relatively low maximum of cell growth rate (micro(max) = 0.21 h(-1)).
桉木酸性亚硫酸盐制浆的废蒸煮液（HSSL）是亚硫酸盐浆生产的副产物，除磺化木质素外，还含有降解半纤维素产生的糖，主要是戊糖。本工作的主要目标是利用毕赤酵母发酵这些糖生产生物乙醇。发酵培养基中 HSSL 比例的增加对乙醇产率有负面影响。因此，在 20%（v/v）的 HSSL 下，最大乙醇产率为 0.15 g(e) g(s)(-1)，而在 60%（v/v）时仅为 0.08 g(e) g(s)(-1)。离子交换树脂处理可生物去除 HSSL 中的乙酸，但需要完全去除乙酸和多酚（包括磺化物质），才能实现高效的生物乙醇生产。因此，促进了毕赤酵母的发酵代谢途径，在相对较低的最大细胞生长速率（micro(max) = 0.21 h(-1)）下，实现了较高的乙醇生产力和产率（Yp/s = 0.49 g(e) g(s)(-1))。
