Fermentation of lignocellulosic hydrolyzate using a submerged membrane bioreactor at high dilution rates

Abstract

Please cite this article as: Ylitervo, P., Doyen, W., Taherzadeh, M.J., Fermentation of lignocellulosic hydrolyzate using a submerged membrane bioreactor at high dilution rates, Bioresource Technology (2014), doi: http:// dx.doi.org/10. 1016/j.biortech.2014.04.066 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 1Fermentation of lignocellulosic hydrolyzate using a submerged 1 membrane bioreactor at high dilution rates and 0.8 h -1 with the increase of dilution rate. Results show that the yeast in the sMBR 7 was able to ferment the wood hydrolyzate even at high dilution rates, attaining a 8 maximum volumetric ethanol productivity of 7.94 ± 0.10 g L -1 h -1 at a dilution rate of 9 0.8 h -1 . Ethanol yields were stable at 0.44 ± 0.02 g g -1 during all the tested dilution rates, 10 and the ethanol productivity increased from 2.16 ± 0.15 to 7.94 ± 0.10 g L -1 h -1 . The 11 developed sMBR systems running at high yeast density demonstrates a potential for a 12 rapid and productive ethanol production from wood hydrolyzate. 13 14

Current progress in high cell density yeast bioprocesses for bioethanol production

“…For example, a medium containing 17.0 g/L furfural could be continuously fermented by using a membrane bioreactor to obtain cell densities of up to 180 g cell dry weight/L [45]. Furthermore, Ylitervo et al showed that continuous fermentation of spruce hydrolysate was possible at dilution rates of 0.8 h –1 in a submerged membrane bioreactor at cell densities of 60 g cell dry weight/L [46].…”

Membrane bioreactor: A mini review on recent R&D works

“…The membrane completely retained the biomass, which then was partly recycled into the bioreactor to maintain a high biomass concentration, to operate at both high dilution and high growth rates. Ylitervo et al (2014) applied submerged MBR to enrich density of Saccharomyces cerevisiae for fermenting toxic lignocellulosic hydrolyzate to ethanol. The MBR demonstrated rapid and productive ethanol production from wood hydrolyzate.…”

Lignocellulosic bioethanol production: prospects of emerging membrane technologies to improve the process – a critical review

“…Specific agricultural lignocellulosic waste substances such as rice straw and wheat straw (Ishola et al 2013, 2015a,b, Ylitervo et al 2014, Zahed et al 2016 have been mainly exploited in experimental studies of membrane reactor facilitated lignocellulosic bioethanol production process. In some experimental studies (Lee et al 2000, Ylitervo et al 2014, general lignocellulosic hydrolyzate materials were investigated in MBR-based bioethanol production process. Information related to specific lignocellulosic substrates used until now for MBR facilitated bioethanol production, maximum product concentration or productivity achieved, and membrane materials or modules used in those studies are represented in Table 2.…”

“…Another advantage of such membrane cell recycle fermentation system (MBR) is that the dilution rate is not dependent on the growth rate of the microorganism (Ylitervo et al 2013). High dilution rates lead to maximum bioethanol productivity and yields (Ylitervo et al 2014). Low dilution rates are the only possible operating conditions in which traditional continuous cultivation systems without cell recycle are successful (Brandberg et al 2008).…”

“…Intermittent product removal through membrane processes during saccharification and fermentation processes enables to overcome product inhibition problem. On the other side, long-term performance of membrane in fouling free conditions can be ensured by virtue of sweeping flow in flat-sheet cross-flow modular operation of membrane or through sMBR system, which facilitates such operation with less energy involvement (Ylitervo et al 2014).…”