Scholarly article on topic 'Bioethanol Production from Oil Palm Frond by Simultaneous Saccharification and Fermentation'

Bioethanol Production from Oil Palm Frond by Simultaneous Saccharification and Fermentation Academic research paper on "Agriculture, forestry, and fisheries"

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Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — Sureeporn Kumneadklang, Siriporn Larpkiattaworn, Chaisit Niyasom, Sompong O-Thong

Abstract Ethanol production from oil palm frond (OPF) by simultaneous saccharification and Saccharomyces cerevisiae TISTR5048 fermentation was investigated. Solid fraction of OPF (20% TS) was pretreated by 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 presoaking at room temperature for 24hours. Pretreated OPF by presoaking in 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 contained 37%, 42% and 49% of cellulose, respectively. Pretreated OPF was simultaneous saccharification by cellulase enzyme (Cellic CTec2, Novozymes) and sequentially fermentation. Sugar concentration in OPF cellulose hydrolysis of 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 presoaking was 45.72, 55.73 and 56.94g/l, respectively. Ethanol concentration of 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 presoaking was 14.5, 15.0 and 17.2g/L, respectively. 2% NaOH in H2O2 presoaking was the best pretreatment with 82.11% of total solids recovery and containing 49.9% of cellulose with enzyme digestion ability of 37.6%.

Academic research paper on topic "Bioethanol Production from Oil Palm Frond by Simultaneous Saccharification and Fermentation"

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Energy Procedia 79 (2015) 784 - 790

2015 International Conference on Alternative Energy in Developing Countries and

Emerging Economies

Bioethanol Production from Oil Palm Frond by Simultaneous Saccharification and Fermentation

Sureeporn Kumneadklangab, Siriporn Larpkiattawornb, Chaisit Niyasomc,

Sompong O-Thong a'd'e*

a Biotechnology Program, Faculty of Science, Thaksin University, Phatthalung, Thailand bThailand Institute of Scientific and Technological Research, Tambon Klong 5 Khlong Luang Pathum Thani, Thailand cDepartment of Biology, Faculty of Science, Thaksin University, Phatthalung, Thailand, d Research Center in Energy and Environment, Faculty of Science, Thaksin University, Phatthalung, Thailand eResearch Group for Development of Microbial Hydrogen Production Process from Biomass, Khon Kaen University, Khon Kaen,

Thailand

Abstract

Ethanol production from oil palm frond (OPF) by simultaneous saccharification and Saccharomyces cerevisiae TISTR5048 fermentation was investigated. Solid fraction of OPF (20% TS) was pretreated by 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 presoaking at room temperature for 24 hours. Pretreated OPF by presoaking in 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 contained 37%, 42% and 49% of cellulose, respectively. Pretreated OPF was simultaneous saccharification by cellulase enzyme (Cellic CTec2, Novozymes) and sequentially fermentation. Sugar concentration in OPF cellulose hydrolysis of 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 presoaking was 45.72, 55.73 and 56.94 g/l, respectively. Ethanol concentration of 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 presoaking was 14.5, 15.0 and 17.2 g/L, respectively. 2% NaOH in H2O2 presoaking was the best pretreatment with 82.11% of total solids recovery and containing 49.9% of cellulose with enzyme digestion ability of 37.6%.

© 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-reviewunderresponsibility oftheOrganizing Committeeof2015 AEDCEE

Keywords: Ethanol production, Oil palm frond, Preteatment, Simultaneous saccharification and fermentation

* Corresponding author. Tel.: +66 746 09600; fax: +66 746 93992. E-mail address: sompong.o@gmail.coom

1876-6102 © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the Organizing Committee of 2015 AEDCEE doi: 10.1016/j .egypro .2015. 11.567

1. Introduction

The world population has grown resulting to high energy consumption and more countries has become industrialized. The fossil fuels, such as crude oil, coal and natural gas have been the major resources to meet the increased energy demand. However, they are gradually being depleted to extinction because they are not renewable. Moreover, serious environmental and ecological problems have been increased during their exploitation and use. Therefore, there is great interest in exploring alternative energy sources to maintain the sustainable growth of society [1]. Fuel ethanol production from lignocellulosic biomass is emerging as one of the most important technologies for sustainable production of renewable transportation fuels. Ethanol has a higher octane rating than gasoline and produces fewer emissions, therefore being widely recognized as a substitute and/or additive to gasoline [2]. In terms of chemical composition, the oil palm biomass predominantly contains of cellulose (40-50%), hemicelluloses (2035%) and lignin (16-29%) [3]. Ethanol production from lignocellulosic materials consists the third main process; the first, size reduction and pretreatment for delignification are necessary to release cellulose and hemicellulose is for hydrolysis; the second, hydrolysis of cellulose and hemicellulose uses enzyme or other method to produce the glucose, xylose, arabinose, galactose, manose; the third, fermentation of reducing sugar to ethanol. The production of sequential acid/alkali-pretreated empty palm fruit bunch fiber gave ethanol production of 37.8 g/L [4]. Eethanol production from palm pressed fiber by simultaneous saccharification and fermentation has ethanol production of 10.4 g/L [5]. Oil palm frond (OPF) is a agriculture waste. It has large amount from cut off during harvesting of fresh fruit bunch (FFB). The OPF was cutting in every 20 days/time and left in palm groove as fertilizer for palms. The utilization of OPF for ethanol production could increased the value of OPF and a new raw material to produce ethanol in the future [6]. This research aimed to optimized the conditions for the pretreatment of OPF for cellulose hydrolysis by enzymatic hydrolysis and ethanol fermentation (SSF) by Saccharomyces cerevisiae.

2. Materials and Methods

2.1 Raw materials

Oil palm frond (OPF) was cut into small pieces and dried at 90°C for 24 hours to remove the moisture. Thereafter, it was grind to 0.2 - 2 mm in size and soaked in water by the ratio 1:4 for 24 hours. Then, the raw material was squeezed to collecting OPF juice and store in refrigerator at 4°C. The solid fraction was dried in an oven with the temperature of 90°C for 24 hours and to put in plastic bag at room temperature for future work. The solid fraction used for pretreatment.

2.2 Pretreatment of oil palm frond

Chemical pretreatment with sulfuric acid, sodium hydroxide and sodium hydroxide in hydrogen peroxide was carried out in 250 ml flask. 20% w/v of solid fraction was loaded in the flask. In experimental, the solid fraction of oil palm frond (20% TS) was pretreated by 2% sulfuric acid, 2% sodium hydroxide and 2% sodium hydroxide in hydrogen peroxide presoaking for 24 hours at room temperature. OPF was filter and solid fraction was dried and used as the substrate for SSF process and ethanol production process. The composition of treated OPF was analyzed for cellulose, hemi-cellulose and lignin content.

2.3 Enzyme hydrolysis and ethanolproduction

Ethanol production from OPF cellulose by simultaneous saccharification and fermentation (SSF) was tested in a batch mode. The enzymatic hydrolysis was done in volumetric flask 250 ml by using 15% (w/w) of the treated material. Then, the 5 ml citrate buffer at a concentration of 5 M and pH 4.8 was added to 88 ml of distilled water. Thereafter, the flask was sterilized at 121 °C for 15 min. Hydrolysis by added 2 ml cellulase enzyme (123 FPU Cellic CTec2, Novozymes). Then, the mixture was incubated at 50°C with shaking at 150 rpm for 72 hours and samples were collected for analysis at 0, 24, 48,and 72 hours. Then, 10% (v/v) of S. cerevisiae and 1% (v/v) yeast extract was added. Finally, the samples were incubated at 30°C with shaking at 150 rpm for 24 hours and collected for analysis at 0, 24, 48, 72 and 96 hours to analyze reducing sugar and ethanol concentration.

2.4 Ethanol production from OPF hydrolysates mixed with OPF juice

Ethanol production from OPF cellulose hydrolysates mixed with OPF juiced at 10%, 20%, 30%, 40% and 50% v/v, respectively, instead of 1% yeast extract addition. 10% (v/v) yeast inoculum was added and incubated at 30 °C with shaking at 150 rpm for 24 hours and incubated for 96 hours. Liquid solution was analyzed for reducing sugar and ethanol concentration.

2.5 Analytical methods

The reducing sugar concentration was estimated using 3,5-dinitrosalicylic acid (DNS) method [7]. The chemical compositions of the residues resulted from pretreatment analyzed by Karlsson method [8]. FTIR spectroscopic investigations evidenced the capacity of different absorption bands to characterize the ordering degree of the cellulosic polymers [9]. The ethanol and sugar was analyzed HPLC and ebulliometer.

3. Results and Discussion

3.1 Chemical composition of OPF

The composition of initial raw OPF was contain of 41.9% of cellulose, 36.0% of hemicellulose and 22.0% of lignin. Cellulose containing in treated OPF at 20% solids presoaking in 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 was contain of 37, 42 and 49% of cellulose, respectively. Chemical pretreatment with 2% NaOH in H2O2 presoaking was the best pretreatment with 82.11% of total solids recovery and containing of cellulose (49.93%), hemicelluloses (30.07%) and lignin (20.00%) (Table1).

Table 1. Chemical composition of raw oil palm frond (OPF) and treated OPF

Composition

Treatment Cellulose (%) Hemi- cellulose (%) Lignin (%)

2% (v/v) H2SO4 treated OPF 37.2 32.7 30.0

2%(w/v) NaOH treated OPF 42.3 29.7 28.0

2% (w/v) NaOH in H2O2 treated OPF 49.9 30.1 20.0

raw OPF 41.9 36.1 22.0

3.2 Effects of the enzyme hydrolysis and ethanol production of treated OPF

The solid fraction from pretreated OPF with 2% H2SO4, 2% NaOH and 2% NaOH in H2O2 was hydrolyzed by cellulase enzyme 123 FPU (Cellic CTec2, Novozymes) at a concentration of OPF 15% w/w for 72 hours. The result showed that pretreated OPF with 2% NaOH in H2O2 treated OPF was the better enzyme hydrolysis and gave the maximum sugar concentration of 56.9 g/L (Fig.1). Enzymatic hydrolysis of 2% H2SO4 and 2% NaOH treated OPF by cellulase enzyme was 45.72 and 55.73 g/l, respectively, with enzyme digestion ability of 37.5 % (Table 2).

H2S01 20g treated OPF —Ш— NaOH 20g treated OPF -*-NaOHтН202 20g treated OPF -X- avicel —'— raw OPF 120.0 -1-

0 24 48 72 96 120 144 168 192

Incubation time (h)

Fig 1. Sugar concentration during enzymatic hydrolysis of treated OPF and yeast fermentation. Table 2. Enzyme digestion efficiency of raw OPF and treated OPF

Condition_Sugar concentration (g/L)_Enzyme digestion (%)

2%(v/v) H2SO4 treated OPF 45.73 30.18

2%(w/v) NaOH treated OPF 55.74 36.79

2%(w/v) NaOH in H2O2 treated OPF 56.95 37.59

raw OPF 32.44 21.41

Fig 2. Ethanol production by Saccharomyces cerevisiae from treated OPF hydrolysis

CH2OH CH OI i CH2OH

H h— O , H k— O 1 H A— O

J./H NJN. J/h i/H \JN.

C-H stretching

OH-stretching \

Cellulose structure

C-O-C stretching CH2 bending

P-1,4-glycosidic

Fig 3. FTIR spectra of avicel (control), 2% NaOH treated OPF (A) and 2% NaOH in H2O2 treated OPF (B)

Ethanol production from cellulose hydrolysate of 2% (w/v) NaOH in H2O2 pretreated OPF by S. cerevisiae gave high amount of ethanol concentration of 17.2 g/l. Ethanol production from NaOH in H2O2 treated OPF was higher than 2% H2SO4 treated OPF and 2% NaOH treated OPF with ethanol concentration of 14.5 and 15.0 g/L (Fig 2). FTIR also shown high cellulose fraction of 2% NaOH in H2O2 treated OPF when compared with raw OPF (Fig.3). FT-IR spectroscopy has been extensively used in cellulose research, since it presents a relatively easy method of obtaining direct information on chemical changes that occur during various chemical treatments. The broad band in the 3600-3100 cm-1 region, which is due to the OH-stretching vibration, gives considerable information concerning the hydrogen bonds. The shift of the band from 2900 cm-1, corresponding to the C-H stretching vibration. In addition, the FTIR absorption band at 1430 cm-1, assigned to a symmetric CH2 bending vibration, decreases. The FTIR absorption band at 1030 cm-1, assigned to C-O-C stretching and 898 cm-1 assigned to P-1,4-glycosidic [7]. The FTIR analyses of oil palm frond was pretreated by 2% sulfuric acid, 2% sodium hydroxide and 2% sodium hydroxide in hydrogen peroxide, all samples are characterized by the structure of cellulose after pretreatment with the cellulose structure is the same, compared with controls.

3.3 Effects of OPF juice addition to OPF hydrolysates on ethanol production

The result showed that ethanol production using OPF hydrolysates and mixed with OPF juice was not significant different with OPF hydrolysates alone. But can reduced the addition of yeast extract could be reduction of production cost in large scale. Production of ethanol from OPF hydrolysates and mixed OPF juice at 20% v/v and followed by S. cerevisiae fermentation gave maximum ethanol production of 17.5 g/L. Ethanol production from OPF hydrolysates and mixed with OPF juice at 10%, 30%,40 and 50% was

15, 13,12 and 12g/L, respectively. The mass and energy balance were used for assessing the energy output of OPF in the SSF process (Fig. 4) of OPF can produce to total ethanol and methane were 47.7 g ethanol (SAP = 13g/L-ethanol, SSF = 17.20 g/L ethanol, Hydrolyses and mixed the juice squeezed = 17.5 g/L ethanol).

Table 3. Ethanol production using treated OPF hydrolysates and mixed OPF juice

Material_Concentration of juice squeezed of oil palm frond (%)_Ethanol (g/L)

10 15.0

20 17.5

Oil palm frond 30 13.0

40 12.0

50 12.0

10 32.0

20 40.0

Avicel (control) 30 37.5

40 32.5

50 35.0

Raw OPF 10 13.0

juice squeezed of oil palm frond 50 13.0

juice squeezed of oil palm frond 100 13.5

-Cellulose 41.94%

- Hemicelluloses 36.06%

- Lignin 22%

17.50g'I ethanol

Fig 4. Mass and energy balance of the ethanol from OPF

4. Conclusion

OPF treated with 2% (w/v) sodium hydroxide in hydrogen peroxide had high cellulose content and also better enzyme with sugar concentration of 56.9 g/L in 15% TS hydrolysis. The fermentation of cellulose hydrolysate by Saccharomyces cerevisiae gave maximum ethanol about 17.2 g/L. Ethanol production from OPF hydrolysates mixed OPF juice squeezed at 20% v/v was 17.5 g/L. The chemical pretreated using sodium hydroxide in hydrogen was an efficient pretreatment method of OPF for its ethanol production.

Acknowledgements

Would like to thank Agricultural Research Development Agency (Public Organization) and Thailand Institute of Scientific and Technological Research, for the financial support.

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