abstract
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, plainly 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=0.49g(e)g(s)(-1)) at relatively low maximum of cell growth rate (mu(max)=0.21 h(-1)). (C) 2009 Elsevier Ltd. All rights reserved.
keywords
ETHANOL-PRODUCTION; FUEL ETHANOL; YEAST; ACID; DETOXIFICATION; HYDROLYSATE; PRODUCTS; GLOBULUS; XYLOSE; TRENDS
subject category
Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels
authors
Xavier, AMRB; Correia, MF; Pereira, SR; Evtuguin, DV
our authors
Ana Maria Rebelo Barreto Xavier
Assistant Professor
Dmitry Evtyugin
Associate Professor with Aggregation
Susana Raquel de Sousa Pereira
PhD Studentacknowledgements
The financial support provided by European innovation PRIME Program (Grant SIME I&DT no. 00/22689) is greatly acknowledged. Authors acknowledge Eng. A. Prates from CAIMA, Industria de Celulose S.A., Constancia, Portugal for the technical assistance during this work. Authors also acknowledge and pay tribute to the late Professor Isabel Spencer-Martins for her helpful consultations regarding the biological removal of acetic acid and for the deacidificant yeasts supply.