Assessment of bioethanol yield by S. cerevisiaegrown on oil palm residues: Monte Carlo simulation and sensitivity analysis

Published Date
Bioresource Technology
January 2015, Vol.175:417–423, doi:10.1016/j.biortech.2014.10.116

Author 

• Mohd Dinie Muhaimin Samsudin
• Mashitah Mat Don ^,

• School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang, Malaysia

Received 11 September 2014. Revised 21 October 2014. Accepted 23 October 2014. Available online 30 October 2014. 

Highlights

• •
  Bioethanol yield changes due to heterogeneity of substrates, OPT sap and POME.
• •
  Monte Carlo simulation was applied for uncertainty analysis.
• •
  Consistent results were obtained although model parameters fluctuating around 5%.
• •
  Sensitivity analysis was applied for identification of critical parameters.
• •
  Bioethanol fermentation performance highly depends on the growth of yeast.

Abstract

Oil palm trunk (OPT) sap was utilized for growth and bioethanol production by Saccharomyces cerevisiae with addition of palm oil mill effluent (POME) as nutrients supplier. Maximum yield (Y_P/S) was attained at 0.464 g bioethanol/g glucose presence in the OPT sap–POME-based media. However, OPT sap and POME are heterogeneous in properties and fermentation performance might change if it is repeated. Contribution of parametric uncertainty analysis on bioethanol fermentation performance was then assessed using Monte Carlo simulation (stochastic variable) to determine probability distributions due to fluctuation and variation of kinetic model parameters. Results showed that based on 100,000 samples tested, the yield (Y_P/S) ranged 0.423–0.501 g/g. Sensitivity analysis was also done to evaluate the impact of each kinetic parameter on the fermentation performance. It is found that bioethanol fermentation highly depend on growth of the tested yeast.

Keywords

Oil palm residues

Bioethanol

Modeling

Monte Carlo simulation

Sensitivity analysis

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Nomenclature

S_o

initial glucose concentration (g/L)

S

value of response

t

time (h)

V₁

the bioethanol yield with all model parameter remained unchanged

V₂

the bioethanol yield with a single kinetic model parameters adjusted to ±10% or ±50%

X_o

initial biomass and suspended solids (g/L)

X_m

maximum attainable biomass and suspended solids concentration (g/L)

α

growth-associated product formation coefficient (g/g)

β

non-growth-associated product formation coefficient (g/g h)

γ

growth-associated substrate consumption coefficient (g/g)

δ

non-growth-associated substrate consumption coefficient (g/g h)

μ_m

maximum specific growth rate (h⁻¹)

 Table 1

Table 1.

 Table 2

Table 2.

 Table 3

Table 3.

Fig. 1.

 Table 4

Table 4.

 Table 5

Table 5.

Fig. 2.

 Table 6

Table 6.

• ⁎ 
  Corresponding author. Tel.: +60 4 5996468; fax: +60 4 5941013.

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