BioChem - DOS

Improved permselectivity of forward osmosis membranes for efficient concentration of pretreated rice straw and bioethanol production

Journal of membrane science

Zhang, Yihan; Nakagawa, Keizo; Shibuya, Masafumi; Sasaki, Kengo; Takahashi, Tomoki; Shintani, Takuji; Yoshioka, Tomohisa; Kamio, Eiji; Kondo, Akihiko; Matsuyama, Hideto

<P><B>Abstract</B></P> <P>The hydrothermal pretreatment of rice straw generates a liquid fraction that contains low concentrations of sugars, as well as fermentation inhibitors which are not favourable for efficient bioethanol production. For the development of a forward osmosis (FO) process to concentrate sugars and remove fermentation inhibitors, we fabricated polyamide-polysulfone (PA-PSf) membranes treated with NaClO solution. The NaClO treatment improved the water permeability (<I>A</I> value) and the permselectivity of fermentation inhibitors against sugars. Maximum separation of xylose from furfural and acetic acid was achieved when the treated membranes had <I>A</I> values of 5.5&ndash;7 L m<SUP>&minus;2</SUP> h<SUP>&minus;1</SUP> bar<SUP>&minus;1</SUP>. Using an optimized membrane with <I>A</I> value of approximately 6 L m<SUP>&minus;2</SUP> h<SUP>&minus;1</SUP> bar<SUP>&minus;1</SUP>, a liquid fraction from hydrothermally pretreated rice straw was concentrated in a one-step FO process to increase sugar concentrations and decrease fermentation inhibitor concentrations. The ethanol concentration and yield (ethanol/total sugar) by xylose-utilizing <I>Saccharomyces cerevisiae</I> reached 18.0 g/L and 0.40, respectively, which were much higher than those obtained with commercial FO membranes. These results clearly indicate the possibility of introducing a simple and low-cost FO process into bioethanol production from lignocellulosic biomass by incorporating NaClO treatment to FO membrane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> FO process was used to concentrate sugars and remove fermentation inhibitors. </LI> <LI> Polyamide-polysulfone membranes were treated with NaClO solution. </LI> <LI> Water permeability and sugars/fermentation inhibitors selectivity were improved. </LI> <LI> A liquid fraction was concentrated in a one-step FO process. </LI> <LI> Higher ethanol concentration and yield were achieved than those obtained with commercial FO membranes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

2018

Elsevier

0376-7388

1873-3123

566

pp.15-24

10.1016/j.memsci.2018.08.046

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART89937211

Forward osmosis membrane; Permselectivity; NaClO treatment; Concentration of rice straw; Bioethanol