Bioprocess and Biosystems Engineering

, Volume 29, Issue 1, pp 49–57

Very high ethanol productivity in an innovative continuous two-stage bioreactor with cell recycle

  • F. Ben Chaabane
  • A. S. Aldiguier
  • S. Alfenore
  • X. Cameleyre
  • P. Blanc
  • C. Bideaux
  • S. E. Guillouet
  • G. Roux
  • C. Molina-Jouve
Original paper

DOI: 10.1007/s00449-006-0056-1

Cite this article as:
Ben Chaabane, F., Aldiguier, A.S., Alfenore, S. et al. Bioprocess Biosyst Eng (2006) 29: 49. doi:10.1007/s00449-006-0056-1

Abstract

The performance of an innovative two-stage continuous bioreactor with cell recycle—potentially capable of giving very high ethanol productivity—was investigated. The first stage was dedicated to cell growth, whereas the second stage was dedicated to ethanol production. A high cell density was obtained by an ultrafiltration module coupled to the outlet of the second reactor. A recycle loop from the second stage to the first one was tested to improve cell viability and activity. Cultivations of Saccharomyces cerevisiae in mineral medium on glucose were performed at 30°C and pH 4. At steady state, total biomass concentrations of 59 and 157 gDCW l−1 and ethanol concentrations of 31 and 65 g l−1 were obtained in the first and second stage, respectively. The residual glucose concentration was 73 g l−1 in the first stage and close to zero in the second stage. The present study shows that a very high ethanol productivity (up to 41 g l−1 h−1) can indeed be obtained with complete conversion of the glucose and with a high ethanol titre (8.3°GL) in the two-stage system.

Keywords

Cell recycleEthanolFermentationSaccharomyces cerevisiaeTwo-stage bioreactor

List of symbols

Ac

Acetic acid concentration (g l−1)

BalanceC

Carbon balance (Cmol h−1 l−1)

BalanceR

Degree of reduction balance (Cmol h−1 l−1)

G

Glycerol concentration (g l−1)

MAc

Molar mass of acetic acid (30 g Cmol−1)

\(M_{{{{\rm CO}}_{2} }}\)

Molar mass of carbon dioxide (44 g Cmol−1)

MG

Molar mass of glycerol (30.67 g Cmol−1)

\(M_{{{{\rm O}}_{2} }}\)

Molar mass of oxygen (32 g Cmol−1)

MP

Molar mass of ethanol (23 g Cmol−1)

MS

Molar mass of glucose (30 g Cmol−1)

MSuc

Molar mass of succinic acid (29.5 g Cmol−1)

MX

Molar mass of biomass (26.3 g Cmol−1)

P

Ethanol concentration (g l−1)

qAc

Acetic acid specific production rate (g g−1 h−1)

\(q_{{{{\rm CO}}_{2} }}\)

Carbon dioxide specific production rate (g g−1 h−1)

Qf

Volumetric feeding rate (l h−1)

qG

Glycerol specific production rate (g g−1 h−1)

\(q_{{{{\rm O}}_{2} }}\)

Oxygen specific consumption rate (g g−1 h−1)

qP

Ethanol specific production rate (g g−1 h−1)

Qm

Volumetric medium feed flow rate (l h−1)

Qp

Volumetric flow rate of the outlet permeate (l h−1)

Qpg

Volumetric flow rate of the second stage bleed (l h−1)

qS

Glucose specific consumption rate (g g−1 h−1)

Qs

Volumetric substrate feed flow rate (l h−1)

Qw

Volumetric water feeding rate (l h−1)

Q12

Volumetric flow rate from first stage to second stage (l h−1)

Q21

Volumetric flow rate from second stage to first stage (l h−1)

rAc

Acetic acid consumption rate (g l−1 h−1)

\(r_{{{{\rm CO}}_{2} }}\)

Carbon dioxide production rate (g l−1 h−1)

rG

Glycerol production rate (g l−1 h−1)

\(r_{{{{\rm O}}_{2} }}\)

Oxygen consumption rate (g l−1 h−1)

rP

Ethanol production rate (g l−1 h−1)

RQ

Respiratory quotient (mol mol−1)

rS

Glucose consumption rate (g l−1 h−1)

rSuc

Succinic acid production rate (g l−1 h−1)

\(r_{{X_{\rm v}}}\)

Viable cell growth rate (g l−1 h−1)

S

Substrate concentration (g l−1)

Sf

Substrate concentration feed (g l−1)

Suc

Succinic acid concentration (g l−1)

t

Time (s)

V

Volume (l)

Xt

Total cell concentration (g l−1)

Xv

Viable cell concentration (g l−1)

Y•/S

Yield on substrate (g g−1)

Y•/X

Yield on biomass (g g−1)

Greek letters

λAc

Reduction degree of acetic acid Cmole (4.0)

λG

Reduction degree of glycerol Cmole (4.67)

\(\lambda_{{{{\rm O}}_{2} }}\)

Reduction degree of oxygen (−4.0)

λP

Reduction degree of ethanol Cmole (6.0)

λS

Reduction degree of glucose Cmole (4.0)

λSucc

Reduction degree of succinic acid Cmole (3.5)

λX

Reduction degree of biomass Cmole (4.2)

μ

Specific growth rate (h−1)

ρ

Cell dry mass per unit of wet cells (g l−1)

Subscripts

g

Global

1

First reactor

2

Second reactor

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • F. Ben Chaabane
    • 1
  • A. S. Aldiguier
    • 1
  • S. Alfenore
    • 2
  • X. Cameleyre
    • 3
  • P. Blanc
    • 1
  • C. Bideaux
    • 1
  • S. E. Guillouet
    • 1
  • G. Roux
    • 4
  • C. Molina-Jouve
    • 1
    • 5
  1. 1.Biotechnology and Bioprocess Laboratory, UMR CNRS 5504 INRA 792Toulouse CedexFrance
  2. 2.Laboratory of Chemical Engineering and EnvironmentToulouse CedexFrance
  3. 3.CRITT Bio-IndustryToulouse CedexFrance
  4. 4.Laboratory for Analysis and Architecture of Systems, LAAS-CNRSToulouse CedexFrance
  5. 5.Laboratoire de Biotechnologie et BioprocédésInstitut National des Sciences AppliquéesToulouse CedexFrance