IJERD – International Journal of Environmental and Rural Development (2015) 6-2

Research article
erd

The Study of Greenhouse Gas Emissions of Ethanol
Production from Agro-industrial Fruit Residues
SOMPORN PLEANJAI*
Rajamangala University of Technology Thanyaburi, Pathumthani, Thailand
Email: somporn_p@rmutt.ac.th

PONGSRI SIWARASAK
Rajamangala University of Technology Thanyaburi, Pathumthani, Thailand
Received 3 March 2015

Accepted 15 May 2015(*Corresponding Author)

Abstract Nowadays, bio-ethanol is playing an important role as an alternative fuel forpassenger cars in Thailand. The use of biofuel can reduce greenhouse gas (GHG) emissions
because it is derived from plant materials. This study aimed to analyze greenhouse gas (GHG)
emissions of ethanol production from agro-industrial fruit residues based on a life cycle
approach. The results showed that the life cycle GHG emissions of ethanol production were
found to be 123.10 kg CO2-eq/kg of anhydrous ethanol. The main source of GHG emission was
the electricity used in the process stage (97.83%) and the second was materials and reagentsused in the stage (2.64%). It showed major energy consumption came from the conversionprocess to produce ethanol. Another encouraging result is that 1 kg non-pretreated pineapple
peel waste inputs could produce 525 g of ethanol fuel; or it is was estimated to be 52-53% ofethanol production. Therefore, agro-industrial fruit residues can be feedstock for ethanol
production in Tropical countries.
Keywords LCA, GHG, ethanol, pineapple peel waste

INTRODUCTION
Biofuels are important because they replace petroleum fuels. The emissions of greenhouse gases(GHGs), in particular carbon dioxide (CO2), are expected to reduce when fossil fuels are replaced with
biofuels; because the latter are derived from plant materials. Bioethanol is by far the most widely usedbiofuel for transportation worldwide. Ethanol utilization for sustainable energy in this decade is desired
especially ethanol produced from agricultural waste. The reason is, in the sense of economy andenvironmental prevention, it can reduce greenhouse effects. There are studies on ethanol production
from agricultural waste such as sweet sorghum bagasse, cassava waste, rice straws, and pineapple peelwaste, which are renewable and interesting resources (Itelima et al., 2013; Nigam, 1999; Siwarasak etal., 2006; Siwarasak et al., 2012; and Wang et al., 2012). Ethanol production is an alternative energythat can solve environmental impact and a value added form of solid-waste for agricultural industries,
particularly in Thailand. The bioconversion of cellulose and hemicelluloses to monomeric sugars, forexample, carbohydrates with 5 and 6 carbons are harder to accomplish than the conversion of starch,presently used for bioethanol production (Ohgren et al., 2006). There are several options for alignocelluloses-to-bioethanol process, which is chosen. However, a few data on an environmental
analysis of bioethanol production from agro-industrial fruit residues have been reported. The cassava
waste and rice straws are high potential raw materials to produce ethanol from fermentation. Moreover,pineapple peel is a potential raw material to produce ethanol due to its containing an appreciable
amount of insoluble fiber-rich fraction, which primary consists of cellulose, pectin substances,hemicelluloses, and notable proportions of lignin (Huang et al., 2011). According to Thai Office ofⒸISERD48

IJERD – International Journal of Environmental and Rural Development (2015) 6-2

Agricultural Economics, Thai pineapple products in 2011 were increased by 25.41% compared to theprevious year (OIE, 2012). The products mostly included fresh pineapples and processed pineapple
products. Canned pineapple processing industry is one of the highest potential industries in Thailand,
due to its geography of locating in monsoon region. The skins, cores, and ends of a pineapple are notdiscarded in pineapple canneries but instead used to make a number of products such as vinegar,alcohol, and animal food. Thailand is ranked as the top of the pineapple exporting countries with amarket share of 40-50% (Eapsirimetee et al., 2013). Table 1 shows the 2015 forecasting of farm crop
perennial trees and fruit trees in the whole kingdom including harvested areas, productions, and yieldof pineapple (OAE, 2015). Furthermore, an analysis of supply or productivity of pineapple in Thailand
is also reported in the table. Pineapple peel, a by-product of the pineapple processing industry, accountfor 29-40% (w/w) of total pineapple weight (Choonut et al., 2014). From Table 1, this implies a highpotential of using pineapple peel for ethanol production.
Table 1 Forecasting of farm crop perennial trees, fruit trees and pineapple productivity in
ThailandPineapples
Harvested areas (rais)
Productions (tons)
Yield (kgs/rai)

2013
532,947
2,067,908
3,880

Year
2014
479,072
1,748,222
3,649

2015
476,433
1,702,735
3,574

Quantity±-2,639-45,487-75

Percent±-0.55
-2.60
-2.06

OBJECTIVES
The aim of this study was to investigate the impact of bioethanol production by fermentation fromagro-industrial fruit residues with Trichoderma reesei RT-P1 and Saccharomyces cerevisiae RT-P2 tothe environment and to promote the use of indigenous and renewable sources for transportation fuels.
Life cycle assessment (LCA) was carried out to determine the GHG emissions performance.
Bioethanol from pineapple peel wastes in Thailand was considered in the analysis.
METHODOLOGYLife cycle assessment (LCA) was used as an environmental assessment tool to identify and evaluate
the GHG emissions of bioethanol production from agro-industrial fruit residues (pineapple peel wastes).
LCA methodology used in this study was based on ISO 14040 framework, which consisted of foursteps: goal and scope definition, inventory analysis, impact assessment, and interpretation (Lee andInaba, 2004). The life cycle inventory analysis and impact assessment were carried out based on ISO
14040 for all stages involved in the production of 1 kg of 99.5% ethanol (anhydrous ethanol) frompineapple peel wastes which included transportation and bioethanol conversion, but not cultivation andharvesting. The functional unit (FU) of this study was 1 kg of 99.5% ethanol production. The systemboundary is shown in Fig. 1. Most of input-output data were collected as primary data at the actual
sites in Thailand. These collected data included raw materials used, energy consumption, utilities, andwaste generated within the system boundary. The secondary data were used in this study as necessary
from literatures, calculation, etc. The analyses focused on the three most important GHGs of bioenergy
systems including i.e. carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), with the global
warming potential factors of 1, 25, 298 kg CO2-eq/kg substance, respectively (IPCC, 2007).

ⒸISERD49

IJERD – International Journal of Environmental and Rural Development (2015) 6-2

Pineapple peel
wastesTransport

Chemical substances
EnzymeWater
Electricity

Bioethanol
conversion

Emission to-air-water-soil

Bioethanol

Fig.1 Product system boundary of this study

Fig.1 Product system boundary of this study
Preparation of Raw Materials and Transportation
In this study, pineapple peel waste was tendered by United Winery and Distillery Company limited,
Nakhon Chai Si, Nakhon Pathom province, Thailand. Pickup Trucks with load 560 kg transported
pineapple peel wastes from the factory to Chemical Engineering Laboratory. The laboratory is locatedin Rajamangala University of Technology Thanyaburi, Pathumthani province, Thailand. The transportdistance was 200 km (round trip). The data were collected at the sites. Diesel fuel consumption was
24.5 L per 200 km (Table 2). The samples were dried before performing the experiment.
Bioethanol Conversion
Based on the optimal fermentation conditions obtained from analysis results of orthogonal experiment,
the verification of ethanol conversion was obtained from fermentation by using crude enzyme powder.
Crude enzyme powder was produced from co-culture of Trichoderma reesei RT-P1 andSaccharomyces cerevisiae RT-P2. The ethanol fermentation was carried out in 250 mL shaking flasks
at 120 rpm, by using 8% dried weight of pineapple peels in 100 mL liquid medium for 1 to 5 days
cultivation at initial pH 5 at room temperature (30 oC). Samples were collected daily for analysis ofethanol and reduced sugar concentration. Ethanol concentrations were estimated by the dichromate
colorimetric method (Williams and Reese, 1950), and the reduced sugar concentrations were estimatedto be 3, 5-dinitrosalicyclic acid (Miller, 1959). Three replications were done in this experiment.
RESULTS AND DISCUSSION
Ethanol batch fermentation from pineapple peels wastes with the crude enzyme powder was analyzed.
The results of batch fermentation are shown in Fig. 2. From the figure, ethanol concentration wasinitially around 8 g/L for batch fermentation. Ethanol values increased to 42 g/L on day 4. ThenEthanol concentration decreased to about 18 g/L on day 5. The more increasing ethanol led the moredecrease of sugar due to the enzyme hydrolysis done by cellulose of the crude enzyme powder duringits exponential growth and the decrease of sugar converted to ethanol (Lever et al., 2010; Mamma et al.,1996). In addition, direct energy and material inputs in the ethanol production system are summarizedin Table 2, which the GHG emissions per kg of 99.5% ethanol production were calculated. The
calculated emission results are presented in Fig.3, representing 123.10 kg CO2-eq/kg ethanol. The
assessment reveals that there were wide ranges of GHG emissions depending on the productionⒸISERD50

IJERD – International Journal of Environmental and Rural Development (2015) 6-2504540353025201510504540353025201510g/L Reducing sugar

g/L Ethanol

environment such as type of fuel used in transportation, water consumption, materials and reagents andelectricity used in the ethanol production.

500123reducing sugar

45day

ethanol

Fig. 2 Ethanol and reducing sugar in batch fermentation (SD 3%)
Table 2 Direct material and energy-related input/output associated with ethanol production
systemSegment
Ethanol conversion
pineapple peel waste
EnzymeCaHPO4
MgSO4
Urea
K2PO4
Sugar
WaterElectricityTransportationDiesel used for transport
Ethanol product

Unit

Inputggggggg
LkWh

1000.00
750.0012.50
12.50
100.00187.50375.0012.50
112.70km/L

8.16

Output525.00

The results of this study showed higher ethanol yield than other studies. For example, themaximum yield of bioethanol (9.69g/L) with no hydrogen production by S.cerevisiae with 36 % ofcellulose was achieved from pineapple peel after pretreatment with water and heat at 100 0C for 4 h.
(Choonut et al., 2014). The fermented broth using S. cerevisiae TISTR 5048 with 20.44 % of cellulose
gave the highest percentage of bioethanol yield which was 65 % (Niwaswong et al., 2014). Otherstudies, lignocellulosic ethanol production could alternatively be done from agricultural wastes such as
corn stover, sugarcane bagasse and rice straw (Kadam and McMilland, 2003; Kadam et al., 2000; andKim and Dale, 2004). Lignocellulosic materials represented a promising option as a feedstock forethanol production by considering output/input energy ratios, great availability both in tropical andtemperate climate countries, low cost (primary related to their transport), and ethanol yields (Sánchezand Cardona, 2008). Furthermore, it was found pineapple peel waste is quite simple, uncomplicated,and low cost as it can be applicable in the ethanol production industries.

ⒸISERD51

IJERD – International Journal of Environmental and Rural Development (2015) 6-2Fig. 3 GHG emissions from ethanol production
In Thailand, with its agriculture-based economy, employs 20% of available agricultural residues
through agricultural wastes and by-products. Moreover, there is potential to produce 3.1-8.6 million
liters/day of ethanol (Kumar et al., 2013). However, the great production of ethanol from industrial
fruit residues can entail serious economic and environmental consequences. The greenhouse gas
reduction of ethanol with respect to conventional gasoline, on a well to wheel basis, is about 13% when
ethanol is derived from grain; and up to 90% for sugarcane-based ethanol (Quadrelli and Peterson,2007).
CONCLUSION
The maximum ethanol production was obtained from fermentation crude enzyme powder, which wasproduced from co-culture of Trichoderma reesei RT-P1 and Saccharomyces cerevisiae RT-P2. Ethanol
values increased on day 4 with the use of 8% dried weight of pineapple peels in 100 mL liquid medium
for cultivation at initial pH 5 at room temperature (30oC). Among all processes in the ethanol
production system, ethanol conversion created the highest amount of GHG emissions (electricity used),
up to 97.8% of the total emissions. Materials and reagents used created 2.1% of the total GHG
emissions. The other processes, which were transportation (diesel used) and water consumption createdless than 1% of the total GHG emissions. Another encouraging result was 1 kg of non-pretreatedpineapple peel waste input could produce 525 g of ethanol fuel, or it is estimated to be 52-53% ofethanol production. In this study, pineapple peel was proved as one of the potential raw materials forbioethanol production. Therefore, agro-industrial fruit residues can be used as feedstock for ethanol
production in tropical countries.
ACKNOWLEDGEMENTS
Financial support by the Thailand Research Fund under the Faculty of Science and Technology,
Rajamangala University of Technology Thanyaburi (Grant annual/2011)is gratefully acknowledged.
REFERENCES
Choonut, A., Saejong, M. and Sangkharak, K. 2014. The Production of ethanol and hydrogen from pineapple peel
by Saccharomyces cerevisiae and Enterrobacter aerogenes. Energy Procedia, 52, 242-249.
ⒸISERD52

IJERD – International Journal of Environmental and Rural Development (2015) 6-2

Eapsirimetee, P., Suthikarnnarunai, N. and Harnhiran, S. 2013. Balancing canned pineapple supply chain inThailand. European Journal of Business and Management, 5 (4), 32-39.
Huang, Y.I., Chow, C.J. and Fang, Y.J. 2011. Preparation and physical properties of fiber-rich fraction frompineapple peels as a potential ingredient. J. Food Drug Anal., 19, 318-323.
IPCC. 2007. Working group III report “mitigation of climate change”, Fourth assessment report. Cambridge
University Press.
Itelima, J., Onwuliri, F., Onwuliri, E., Onyimba, I. and Oforji, S. 2013. Bio-Ethanol production from banana,plantation and pineapple peels by simultaneous saccharification and fermentation process. International
Journal of Environmental Science Development, 4 (2), 213-216.
Lee, K. and Inaba, A. 2004. Life cycle assessment best practices of ISO 14040 Series. Asia-Pacific Economic
Co-operation, Singapore, 1-5.
Lever, M., Ho, G. and Cord-Ruwisch, R. 2010. Ethanol from lignocelluloses using crude unprocessed cellulose
from solid-state fermentation. Bioresource Technology, 101, 7083-7087.
Kadam, K.L. and McMillan, J. 2003. Availability of corn stover as a sustainable feedstock for bioethanol
production. Bioresource Technology, 88, 17-25.
Kadam, K.L., Forrest, L.H. and Jacobson, W.A. 2000. Rice straw as a lignocellulosic resource: Collection,processing, transportation, and environmental aspect. Biomass and Bioenergy, 18, 369-389.
Kim, S. and Dale, B.E. 2004. Global potential bioethanol production from waste crops and crop residues.
Biomass and Bioenergy, 26, 361-375.
Kumar, S., Salam, A. P., Shrestha, P. and Ackom, E. K. 2013. An assessment of Thailand’s biofuel development.
Sustainability, 5, 1577-1597.
Mamma, D., Koullas, D., Fountoukidis, G., Kekos, D., Macris, B.J. and Koukios, E. 1996. Bioethanol from sweetsorghum: Simultaneous saccharification and fermentation of carbohydrates by a mixed microbial culture.
Process Biochemistry, 31 (4), 377-381.
Miller, G.L. 1959. Use of dinitrosalicylic acid and reagent for determination of reducing sugar. AnalyticalChemistry, 31, 426-427.
Nigam, J.M. 1999. Continuous ethanol production from pineapple cannery waste. J. Biotecthnol., 72, 197-202.
Niwaswong, C., Chaiyamate, P., Chotikosaikanon, P., and Ruangviriyachai, C. 2014. Simple and enhanced
production of lignocellulosic ethanol by diluted acid hydrolysis process of pineapple peel (Ananas comosus)
waste. African Journal of Biotechnology, 13 (38), 3928-3934.
OAE. 2015. Division of Agricultural Forecasting. Office Agricultural Economics (OAE). Forecasting resulting ofimportant
plant’sjournal(March2015)[Online].
Available:
http://www2.oae.go.th/
forecast/17_MAR2558/Eng/all/wh_e_02.htm
OIE. 2012. Office of Industrial Economics Team. Office of Industrial Economics (OIE). Industrial government(21 January 2012). [Online]. Available: http://www.oie.go.th
Ohgren, K., Bengtsson, O., Gorwa-Grauslund, M.F., Galbe, M., Hahn-Hagerdal, B., and Zacchi, G. 2006.
Simultaneous saccharification and co-fermentation of glucose and xylose in steam-presented corn stover athigh fiber content with Saccharomyces cerevisiae TMB3400. J. Biotechnol., 126: 488-98.
Quadrelli, R. and Peterson, S. The energy-climate change: Recent trends in CO2 emissions from fuel combustion.
Energ. Policy, 35, 5938-5952.
Sánchez, Ơ.J. and Cardona, C.A. 2008. Trends in biotechnological production of fuel ethanol from different
feedstocks. Bioresource Technology, 99, 5270-5295.
Siwarasak, P., Srinophakun, P. and Chatmanop, J. 2006. The study on growth kinetics of Trichoderma reesei inbatch fermentation of cassava waste and rice straws. J. Eng. RMUTT., 8 (2), 94-99.
Siwarasak, P., Pajantagate, P. and Prasertlertrat, K. 2012. Use of Trichoderma reesei RT-P1 crude enzyme
powder for ethanol fermentation of sweet sorghum fresh stalks. Biores. Technol., 107, 200-204.
Wang, W., Zhuang, X., Yuan, Z., Yu, Q., Qi, W., Wang, Q. and Tan, X. 2012. High consistency enzymaticsaccharification of sweet sorghum bagasse pretreated with liquid hot water. Biores. Technol., 108, 252-257.
Williams, M.B. and Reese, D. 1950. Colorimetric determination of ethyl alcohol. Analytical Chemistry 22, 14631582.

ⒸISERD53