초록
<P><B>Summary</B></P><P>Renewable and low‐cost lignocellulosic wastes have attractive applications in bioethanol production. The yeast <I>Saccharomyces cerevisiae</I> is the most widely used ethanol‐producing microbe; however, its fermentation temperature (30–35°C) is not optimum (40–50°C) for enzymatic hydrolysis in the simultaneous saccharification and fermentation (SSF) process. In this study, we successfully performed an SSF process at 42°C from a high solid loading of 20% (w/v) acid‐impregnated steam explosion (AISE)‐treated rice straw with low inhibitor concentrations (furfural 0.19 g l<SUP>−1</SUP> and acetic acid 0.95 g l<SUP>−1</SUP>) using an isolate <I>Pichia kudriavzevii </I>SI, where the ethanol titre obtained (33.4 g<SUB>p</SUB> l<SUP>−1</SUP>) was nearly 39% greater than that produced by conventional <I>S. cerevisiae </I>BCRC20270 at 30°C (24.1 g<SUB>p</SUB> l<SUP>−1</SUP>). In addition, <I>P. kudriavzevii </I>SI exhibited a high conversion efficiency of > 91% from enzyme‐saccharified hydrolysates of AISE‐treated plywood chips and sugarcane bagasse, although high concentrations of furaldehydes, such as furfural 1.07–1.21 g l<SUP>−1</SUP>, 5‐hydroxymethyl furfural 0.20−0.72 g l<SUP>−1</SUP> and acetic acid 4.80–7.65 g l<SUP>−1</SUP>, were present. This is the first report of ethanol fermentation by <I>P. kudriavzevii</I> using various acid‐treated lignocellulosic feedstocks without detoxification or added nutrients. The multistress‐tolerant strain SI has greater potential than the conventional <I>S</I>.<I> cerevisiae</I> for use in the cellulosic ethanol industry.</P>