Optimization of Pretreatment Conditions for Microwave-assisted Alkaline Delignification of Empty Fruit Bunch by Response Surface Methodology
Corresponding email: mrgozan@gmail.com
Published at : 16 Dec 2019
Volume : IJtech
Vol 10, No 8 (2019)
DOI : https://doi.org/10.14716/ijtech.v10i8.3431
Harahap, A.F.P., Rahman, A.A.Sadrina, I.N., Gozan, M., 2019. Optimization of Pretreatment Conditions for Microwave-assisted Alkaline Delignification of Empty Fruit Bunch by Response Surface Methodology . International Journal of Technology. Volume 10(8), pp. 1479-1487
| Andre Fahriz Perdana Harahap | Bioprocess Engineering Program, Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia |
| Azhar Aditya Rahman | Bioprocess Engineering Program, Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia |
| Isni Nur Sadrina | Bioprocess Engineering Program, Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia |
| Misri Gozan | Bioprocess Engineering Program, Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia |
Oil palm empty fruit bunch (OPEFB) is one of the prominent
lignocellulosic wastes from the oil palm industry, and it has the potential for
feedstock in biobased products. However, delignification must be applied. This
study investigated the effect of microwave-assisted alkaline pretreatment of OPEFB
by using response surface methodology with Box-Behnken design (BBD) to find the
optimum pretreatment conditions. OPEFB (30-mesh) was treated with various
concentrations of aqueous sodium hydroxide. The effect of three variables,
microwave power (280-840 W), NaOH concentration (1-3% w/v), and reaction time (3-9 min), was
evaluated to improve lignin removal. The quadratic model indicated that
microwave power of 832.9 W, NaOH concentration of 2.7% (w/v), and a reaction
time of 8.9 min resulted in the highest lignin removal: 88.10%. FTIR and SEM
analysis was also conducted on the untreated and treated OPEFB to evaluate the
effectiveness of the pretreatment. These results
showed that microwave-assisted alkaline pretreatment of OPEFB could effectively
remove the lignin under a relatively short time period and low alkaline
concentration.
Alkaline pretreatment; Lignin; Microwave; Oil palm empty fruit bunch; Response surface methodology
The palm oil industry
continues to grow in response to increased consumption and demand for palm oil.
During the processing of palm oil, OPEFB is produced as solid waste. As
lignocellulosic biomass, OPEFB contains 39.8% cellulose, 17.3% hemicellulose,
and 28.8% lignin (Kim, 2012). OPEFB has great potential to be utilized for the
production of various biochemical products. OPEFB has been specifically used as
feedstock for the production of levulinic acid and furfural; the highest yields
were 52.1 mol% (C6 sugar basis) and 27.94 mol% (C5 sugar basis), respectively
(Gozan, 2018). OPEFB can also be used as a carbon source for the growth medium
of microorganisms like Saccharomyces cerevisiae to produce bioethanol
with the highest yield: 24% (glucose basis) (Hermansyah, 2015).
Due to the complex
lignocellulose structure of OPEFB, pretreatment is required to remove the
lignin, increase the surface area, and increase the lignocellulose’s porosity.
This process will make both cellulose and hemicellulose readily available for
conversion. Alkaline pretreatment is known to be an efficient method for
delignification due to its capability for lignin solubilization and swelling
formation of treated biomass. Alkaline pretreatment of OPEFB has
This study focuses on the optimization of important
variables of OPEFB microwave-assisted alkaline pretreatment: microwave power,
NaOH concentration, and reaction time. The results were statistically processed
using Response Surface Methodology (RSM), which had been used previously to
study the effect of alkaline treatment on the physical properties of OPEFB
(Fatra, 2016). The use of RSM to study the microwave-assisted alkaline
pretreatment of OPEFB is appropriate because there are some external parameters
affecting this process. By using RSM, effective research can be achieved
through the avoidance of higher prices, longer duration, and repetition. The
obtained BBD was very effective in determining the amount of research that
should be carried out by using a formula that consists of a simple combination.
Optimization using response surface design by BBD required random research in
terms of dependent variable combinations to systematically diminish the error
applied previously when studying the optimization of palm oil mill effluent
electrocoagulation (Lubis, 2018).
This study showed that
microwave-assisted alkaline pretreatment using sodium hydroxide was effective
in removing lignin from the lignocellulose structure of OPEFB within a short
period of time. The model obtained from this experiment shows that to achieve
the highest lignin removal of 88.10%, the optimal conditions for the
pretreatment are a combination of microwave power at 832.9 W, a NaOH
concentration at 2.7% (w/v), and a reaction time of 8.9 min. The result was
further confirmed by analysis of FTIR and SEM, which showed that
microwave-assisted alkaline pretreatment caused chemical and morphological
structure changes to OPEFB in terms of lignin removal.
This research was partially funded by BPDP Sawit Indonesia (Contract No: PRJ-20/DPKS/2018) and USAID through the SHERA program:
Center for Development of Sustainable Region (CDSR). In year 2017-2021, this is
led by the Center for Energy Studies-UGM.
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Barlianti, V.B., Dahnum, D., Hendarsyah, H., Abimanyu, H., 2015. Effect of
Alkaline Pretreatment on Properties of Lignocellulosic Oil Palm Waste. Procedia Chemistry, Volume 16, pp. 195–201
Fatra, W., Rouhillahi, H., Helwani, Z., Zulfansyah, Z., Asmura, J., 2016. Effect
of Alkaline Treatment on the Properties of Oil Palm Empty Fruit Bunch Fiber-reinforced Polypropylene Composite. International Journal of Technology, Volume 7(6), pp. 1026–1034
Ferreira, S.L., Bruns, R.E., Ferreira, H.S., Matos, G.D., David, J.M., Brandão, G.C., da Silva, E.G., Portugal, L.A., dos Reis, P.S., Souza, A.S., dos Santos, W.N., 2007. Box-Behnken
Design: An Alternative for the
Optimization of Analytical Methods. Analytica
Chimica Acta, Volume 597(2), pp. 179–186
Gozan, M., Panjaitan, J.R.H., Tristantini, D., Alamsyah, R., Yoo, Y.J.,
2018. Evaluation of Separate and Simultaneous Kinetic Parameters for
Levulinic Acid and Furfural Production from Pretreated Palm Oil Empty Fruit
Bunches. International Journal of
Chemical Engineering, Volume 2018, pp. 1–12
Harahap, A.F.P., Rahman, A.A., Gozan, M., 2019. Microwave Assisted Aqueous
Ammonia Pretreatment of Oil Palm Empty Fruit Bunch: Effect on Lignin Removal and
Morphological Structure. In: Journal of Physics: Conference Series, 1311
012027
Hermansyah, H., Wisman, A.P., Firdaus, D., Arbianti, R., Utami, T.S.,
Kurnia, A., 2015. Effect of Aeration and Nutrients on Saccharomyces Cerevisiae Cultivation using Lignocellulosic Hydrolysate from Empty Fruit Bunch. International Journal of Technology, Volume 6(7), pp. 1110–1118
He, Y., Pang, Y., Liu, Y., Li, X., Wang, K., 2008. Physicochemical Characterization of Rice Straw Pretreated with
Sodium Hydroxide in the Solid State for Enhancing Biogas Production. Energy & Fuels, Volume 22( 4), pp. 2775–2781
Iberahim, N.I., Jahim, J.M., Harun, S., Nor, M.T.M., Hassan, O., 2013. Sodium Hydroxide Pretreatment and Enzymatic
Hydrolysis of Oil Palm Mesocarp Fiber. International
Journal of Chemical Engineering and Applications, Volume 4(3), pp. 101–105
Kim, S., Park, J.M., Seo, J.W., Kim, C.H., 2012. Sequential Acid-/Alkali-Pretreatment
of Empty Palm Fruit Bunch Fiber.
Bioresource Technology, Volume 109, pp. 229–233
Laghari, S.M., Isa, M.H., Laghari, A.J., 2016. Delignification of Palm
Fiber by Microwave Assisted Chemical Pretreatment for Improving Energy
Efficiency. Malaysian Journal of Science,
Volume 35(1), pp. 8–14
Lubis, M.R., Fujianti, D.S., Zahara, R., Darmadi, D., 2018. The
Optimization of the Electrocoagulation of Palm Oil Mill Effluent with a Box-Behnken
Design. International Journal of
Technology, Volume 10(1), pp. 137–146
Nomanbhay, S.M., Hussain, R., Palanisamy, K., 2013. Microwave-assisted Alkaline Pretreatment and Microwave Assisted Enzymatic
Saccharification of Oil Palm Empty Fruit Bunch Fiber for Enhanced Fermentable
Sugar Yield. Journal of Sustainable
Bioenergy Systems, Volume 3(1), pp. 7–17
Piarpuzán, D., Quintero, J.A., Cardona, C.A., 2011. Empty Fruit Bunches
from Oil Palm as a Potential Raw
Material for Fuel Ethanol Production. Biomass
and Bioenergy, Volume 35(3), pp. 1130–1137
Zulkiple, N., Maskat, M.Y., Hassan, O., 2016. Pretreatment of Oil Palm Empty Fruit Fiber (OPEFB) with Aquaeous Ammonia for High Production of Sugar. Procedia Chemistry, Volume 18, pp. 155–161