Bioconversion of Beetle-Killed Lodgepole Pine Using SPORL: Process Scale-up Design, Lignin Coproduct, and High Solids Fermentation without Detoxification

Abstract

Mountain pine beetle killed Lodgepole pine (Pinus contorta Douglas ex Loudon) wood chips were pretreated using an acidic sulfite solution of approximately pH = 2.0 at a liquor to wood ratio of 3 and sodium bisulfite loading of 8 wt % on wood. The combined hydrolysis factor (CHF), formulated from reaction kinetics, was used to design a scale-up pretreatment on 2000 g wood chips at a relatively low temperature of 165 °C that reduced furan formation and facilitated high solids saccharification and fermentation. The pretreated solids and liquor were disk milled together to result in a biomass whole slurry of 25% total solids. The whole biomass slurry was directly used to conduct simultaneous enzymatic saccharification and combined fermentation (SSCombF) using a commercial cellulase and Saccharomyces cerevisiae YRH400 without detoxification. A terminal ethanol titer of 47.1 g L–1 with a yield of 306 L (tonne wood)−1, or 72.0% theoretical, was achieved when SSCombF was conducted at an unwashed solids loading of 18%. The lignosulfonate (LS) from SPORL was highly sulfonated and showed better dispersibility than a high purity commercial softwood LS, and therefore has potential as a directly marketable coproduct.

Integrated approach for effective bioethanol production using whole slurry from autohydrolyzed Eucalyptus globulus wood at high-solid loadings

“…Once again, the results obtained in these fermentation tests can be compared favorably with the literature. Zhou et al [49] obtained similar results (47.1 g/L of ethanol, corresponding to 72% of theoretical yield) using pretreated pine beetle killed lodgepole pine wood by SPORL at 18% of solids loading and S. cerevisiae YRH400 (engineered yeast strain for xylose fermentation). Moreover, Öhgren et al [50] reported an 81.5% of ethanol yield and 21.4 g/L of ethanol using whole slurry from steam-pretreated corn stover with additional xylanases supplementation by SSF.…”

An alternative feedstock of corn meal for industrial fuel ethanol production: Delignified corncob residue

“…Only substrates and enzymes were considered by assuming the operations of the two feedstocks processing were similar. If the delignified corncob residue feedstock is considered as a pure solid waste of the already profitable xylose production as in the present industry scenario (Case 1) (Zhou et al, 2013), it was more advantageous than corn meal in the cost estimation by saving 40% of the total cost ($478.76 and $796.81 per ton of ethanol, respectively). If the delignified corncob residue was assumed to be the same selling price with the original corncob feedstock (Case 2), the cost for the two feedstocks were almost the same ($736.86 and $796.81 per ton of ethanol, respectively).…”

Ultrahigh molecular weight, lignosulfonate-based polymers: preparation, self-assembly behaviours and dispersion property in coal–water slurry

“…It is expected to improve the Mw of LS with low Mw from industrial processes such as SPORL (sulte pretreatment to overcome recalcitrance of lignocelluloses), as reported by Zhou and co-workers. 32 In this paper, ultrahigh Mw, lignosulfonate-based polymer ALSs were prepared and used as an amphiphilic biopolymer to prepare hollow nanospheres via self-assembly. The formation mechanism of hollow spheres was investigated by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS).…”