of process parameters for the production of citric acid from
oil palm empty fruit bunches
Niamul Bari1,2*, Zahangir Alam1,
Suleyman A Muyibi1, Parveen Jamal1 and
1Bioenvironmental Engineering Research Unit (BERU), Department of
Biotechnology Engineering, Faculty of Engineering,
International Islamic University Malaysia (IIUM), Gombak,
50728 Kuala Lumpur, Malaysia.
2Department of Civil Engineering, Rajshahi University of Engineering and
*Corresponding author. E-mail:
Tel: +603-61964571. Fax: +603-61964442.
20 March, 2009
In this study, optimization of process parameters such as
moisture content, incubation temperature and initial pH
(fixed) for the improvement of citric acid production from
oil palm empty fruit bunches through solid state
bioconversion was carried out using traditional
one-factor-at-a-time (OFAT) method and response surface
methodology (RSM). The possible optimum level of moisture
content, incubation temperature, and initial pH were found
from the OFAT study to be 70%, 30 - 32oC and 5.5
- 8, respectively. The optimum moisture content of 70.3%
(v/w) and incubation temperature of 33.1°C
with initial pH of 6.5 gave the maximum production of citric
acid (369.16 g/kg of dry EFB). The analysis of variance
(ANOVA) of the statistical optimization using central
composite design showed that moisture content (p<0.001) and
incubation temperature (p<0.0001) as well as the interaction
of these two parameters were highly significant for the
citric acid production.
citric acid, process condition, optimization, solid state
bioconversion, Aspergillus niger and central
composite design (CCD).