Applied Biochemistry and Biotechnology

, Volume 89, Issue 1, pp 15–30

Bioconversion of cellulose into ethanol by nonisothermal simultaneous saccharification and fermentation

  • Kyeong-Keun Oh
  • Seung-Wook Kim
  • Yong-Seob Jeong
  • Suk-In Hong
Article

DOI: 10.1385/ABAB:89:1:15

Cite this article as:
Oh, K., Kim, S., Jeong, Y. et al. Appl Biochem Biotechnol (2000) 89: 15. doi:10.1385/ABAB:89:1:15

Abstract

The kinetic characteristics of cellulase and β-glucosidase during hydrolysis were determined. The kinetic parameters were found to reproduce experimental data satisfactorily and could be used in a simultaneous saccharification and fermentation (SSF) system by coupling with a fermentation model. The effects of temperature on yeast growth and ethanol production were investigated in batch cultures. In the range of 35–45°C, using a mathematical model and a computer simulation package, the kinetic parameters at each temperature were estimated. The appropriate forms of the model equation for the SSF considering the effects of temperature were developed, and the temperature profile for maximizing the ethanol production was also obtained. Briefly, the optimum temperature profile began at a low temperature of 35°C, which allows the propagation of cells. Up to 10 h, the operating temperature increased rapidly to 39°C, and then decreased slowly to 36°C. In this nonisothermal SSF system with the above temperature profile, a maximum ethanol production of 14.87 g/L was obtained.

Index Entries

Kinetic modelingtemperature profilenonisothermal simultaneous saccharification and fermentation

Nomenclature

k′1

Specific rate of hydrolysis (h)

k′2

Lumped constants (g[L·h])

Km

Michaelis constant of β-glucosidase (g/L)

Kp

Monod saturation constant for ethanol production (g/L)

KG

Monod saturation constant for cell growth (g/L)

K1B

Inhibition constant of cellulase for cellobiose (g/L)

K1G

Inhibition constant of cellulase for glucose (g/L)

K2B

Inhibition constants of β-glucosidase for cellobiose (g/L)

m

Maintenance energy coefficient (h)

P

Ethanol concentration (g/L)

Pm

Ethanol concentration above which cells do not grow (g/L)

P′m

Ethanol concentration above which cells do not produce (g/L)

r1

Volumetric rate of cellulose utilization (g[L·h])

r2

Volumetric rate of cellobiose utilization (g[L·h])

r3

Volumetric rate of cellobiose utilization (g[L·h])

X

Cell concentration (g/L)

λ

Specific rate of enzyme deactivation (h)

λ1

Specific deactivation rate of cellulase (h)

λ2

Specific deactivation rate of β-glucosidase (h)

μm

Maximum specific growth rate (h)

μi

Specific growth rate of cells in the presence of ethanol (h)

μ0

Maximum growth rate of cells in the absence of concentration (h)

vi

Specific rate of ethanol production in the presence of ethanol (h)

v0

Maximum rate of ethanol production in the absence of ethanol (h)

Copyright information

© Humana Press Inc. 2000

Authors and Affiliations

  • Kyeong-Keun Oh
    • 1
  • Seung-Wook Kim
    • 2
  • Yong-Seob Jeong
    • 3
  • Suk-In Hong
    • 2
  1. 1.Department of Industrial ChemistryDankook UniversityCheonanKorea
  2. 2.Department of Chemical EngineeringKorea UniversitySeoulKorea
  3. 3.Department of Food Science and TechnologyChonbuk National UniversityChonjuKorea