resumo
The fermentation of reducing sugars from hardwood (eucalypt) spent sulphite liquor (HSSL) into ethanol by Pichia (Scheffersomyces) stipitis is hindered by concomitant inhibitors of microbial metabolism. The conditions for the HSSL biological treatment step by Paecilomyces variotii were evaluated and optimised. Two different strategies of reactor operation were compared using single batch (B) and sequential batch reactor (SBR). Biological treatment of HSSL in the SBR revealed the best results with respect to the removal of microbial inhibitors. Also, most of inhibitory compounds, acetic acid, gallic acid, pyrogallol, amongst others, were removed from HSSL by P. variotii before the ethanol fermentation. The bio-detoxified HSSL was subjected to a successful fermentation by P. stipitis, attaining a maximum ethanol concentration of 2.4 g L(-1) with a yield of 0.24 g ethanol g sugars(-1). (C) 2011 Elsevier Ltd. All rights reserved.
palavras-chave
FUNGUS PAECILOMYCES-VARIOTII; PICHIA-STIPITIS; SYRINGIC ACID; ETHANOL; DEGRADATION; INHIBITION; SELECTION; XYLOSE
categoria
Agriculture; Biotechnology & Applied Microbiology; Energy & Fuels
autores
Pereira, SR; Ivanusa, S; Evtuguin, DV; Serafim, LS; Xavier, AMRB
nossos autores
Ana Maria Rebelo Barreto Xavier
Professor Auxiliar
Dmitry Evtyugin
Professor Associado com Agregação
Luísa Seuanes Serafim
Professor Auxiliar
Susana Raquel de Sousa Pereira
Estudante de doutoramentoagradecimentos
Authors acknowledge Eng. A. Prates from CAIMA, Industria de Celulose S.A., Constancia, Portugal for HSSL and technical assistance during this work. Authors also thank FCT for the PhD grant of S. R. Pereira (SFRH/BD/64552/2009).