Muhammad Daud Hammasa, S. Hut. MSi.: Februari 2010

REDUCING ENERGY DEPENDENCE IN INDONESIA USING BIOENERGY FROM LIGNOCELLULOCE BIOMASS

Muhammad Daud, S. Hut.

Due to ascent of population and economic growth, energy consumption in the world has increased significantly. According to Prihandana, et al. (2007), demand of energy in the world is supposed will arise by 1,7% until 2030. While, particularly in Asian region, energy will arise by 2,8%. Bigness of energy growth in Asian region is caused by economic and industrial development rapidly particularly in China and India and other developing countries such as Indonesia.
However, increasing of fossil fuels have caused descent of world fuels reserve, so that it can cause this fuels becoming more scarce and theirs price will be increasing dramaticantly. Also, the benefits of liquids derived from fossil fuels carry with them a serious problem. The release of carbon dioxide from vehicle and other industries is one of the largest contributors to the potensial for global warming. But important progress in research and development aimed at obtaining liquid fuels from bomass has evidenced that major potential problems can be attenuated. Development of alternative energy such as biofuels become important to reduce this problems.
There are many resources which can be processed into biofuels in Indonesia that is biodiesel which can be produced from Jatropha curcas, Elais guineensis, Callophyllum inophyllum and also bioethanol such as cana sugar, and molasses. Bioethanol with concentration 99,5% is called Fuel Grade Ethanol (FGE). It currently can be blended typically at 10% levels with gasoline and also called gasohol (Prihandana, et al., 2007).
Utilization bioethanol as a transportation fuel and as a gasoline supplement have been proved more environmental friendly concerns. Biothanol is a clean-burning, high octane fuel that can be readily substituted for gasoline and its combustion result in significant reductions of toxic emissions such as formaldehyde, benzene and 1,3 butadiene, blends ethanol with gasoline increase the octane of the mixture and they reduce carbon monoxide emissions by 10-30%. When ethanol is produced from renewable sources such as biomass it can both decrease urban air pollution and reduce the accumulation of carbon dioxide, on of green house gases. Thus, replacement of gasoline with ethanol, derived from renewable biomass feedstocks that sequester CO2 during growth, is expected to reduce CO2 emissions by 90-100%. (Bruce and Palfreyman, 1998). Besides that, development of biofuels in Indonesia is expected to assure availability of new and renewable energy resources, can increase economic value of forest and also can reduce of proverty and unemployment in Indonesia.
Now, bioethanol production in Indonesia is focused to sugar crops including sugar cane and sugar beets and also starch crops, including wheat, potatoes and sweet potatoes. Current production of fuel etanol is often base on excess agricultural production and it is generally recognized that this volume is too small in comparison with the anticipated levels of production required for total conversión of transportation fuel markets from gasoline to ethanol. It is also apparent that there is the potential for competition with food production for both the sugar and starch feed stock and that prime agricultural lands normally required to produce the foodstuffs should not be diverted for fuel production. Therefore, bioconversion of lignocellulosics biomass into bioethanol is very important to be developed in Indonesia because this resources is more economic. Biomass resources obtainable from lignocellulosic materials such agricultural and forestry residues, municipal solid waste, and various industrial wastes that are not now well utilized, and that often present disposal problems. Theese residues can be derived easily in Indonesian. Also, we could grow woody and herbaceous energy crops and employ underutilized land to support indigenous production of such forms of biomass. Besides renewable, this biofules, also can reduce gases emission which potentially can cause global warming (Bruce and Palfreyman, 1998; Smith, et al., 2003; Samejima, 2008).
More recently research into bioethanol production from lignocellulosics biomass (Ingram, et al., 1997; Bousaid et al., 1998; Spagnuolo, et al., 1999; Smith, et al., 2003; Samejima, 2008). Some of lignocellulosics biomass that have been investigated is bagasse (Martinez, et al., 2000), straw (Neureiter, et al., 2002) and wood (Bousaid, et al., 1998; Stenberg, et al., 2000). Lignocellulosic biomass is typically composed of a complx mixture of three polymers that is cellulose, hemicelluloses and lignin and a small amount of other compounds that are loosely termed extractives. Although this biomass is more economic than sugar and starch but the fermentation of sugars derived from lignocellulosic feedstocks has proven to be more of a process design and operating challenge than traditional sugar or starch based processes. (Bruce and Palfreyman, 1998; Miyafuji, et al., 2003). Therefore, bioconversion lignocellosic biomass into ethanol is needed optimalization of process of bioethanol production especially in pretreatment, saccharification, fermentation, and distillation (Smith, et al., 2003, Samejima, 2008).
Beside optimalization of process of bioethanol production. It is important to produce bioethanol with low in cost. Some of methods to minimize of production cost are production bioethanol by simultaneous sccharification and fermentation (SSF) (Wyman, 1996) or using lignocellulosics biomass that more economic, abundant and can be planted easily. It is also important to increase yield of ethanol with converting both celluloses and hemicelluloses into ethanol.
The evaluation and identification of yeasts for SSF application has generally taken a two-pronged approach. Many investigators concentrated on the identification of thermotolerant and ethanol-tolerant yeast strains which could ferment only glucose, while other groups tried to identify and isolate cellobiose-fermenting yeast strains which could be applied specifically to SSFs of cellulosic subtrates. It is also possible to mix the cultures of cellobiose-fermenting yeast and ethanol tolerant, gulocose-fermenting yeasts and gain supplementation with β-glucosidase and ethanol tolerance at the same time. An ideal yeast should of course be able to ferment cellobiose and sugars obtained from cellulosic biomass or even cellulolytic itself. Several microorganisms have known and often proposed as the best microrganism for SSF of cellulosic hydrolysates are Saccharomyces cereviciae, Schizosaccharomyces sp., Candida sp., and Kluyveromyces sp. with added enzimes from Trichoderma reesei and Aspergillus niger (Sadler, 1993). Several yeast which can produce the enzymes for SSF does not seem to exist in nature, but could constructed by genetic engineering techniques. Some of microorganisms could be and potential to SSF in Indonesia are Aspergillus niger Trichoderma viride and Trichoderma reesei
Some of biomass that have potential to be developed in Indonesia are bamboos and engineered wood waste. Bamboo is one of local commodity that has been known local community. It is easily to be planted and also have high level of production per a year with harvesting time relatively short in time that is 4-5 year. Dransfield and Widjaja (1995) have been investigated anatomical and chemical components in bamboos. As the result, bamboos are contain 50% of pharechyme cell, 40% of fiber dan 10% vascular bundle and sieve tubes. In the other hand, according to Fatriasari and Hermiati (2008), bamboos contain holocelluloses (cellulose and hemicelluloses) is range 73,32-83,80%. Engineered wood wastes such as saw dusts also are potentially to be converted into ethanol. Sanusi (1993) has investigated that wastes from wood industry can attain 45,66% including 8,93% of wood wastes, 14,48% of chips and 22,25% of slabs.
Evaluation and economical optimalization of bioethanol are depend on the many factor such as materials, isolate. Due to interdependent of subprocess steps strongly, so it has been extremely difficult to identify the relative technical or economic merits of each of subprocess variation and their subsequent influence on the final production cost of ethanol.

Muhammad Daud Hammasa, S. Hut. MSi.

Minggu, 28 Februari 2010

REDUCING ENERGY DEPENDENCE IN INDONESIA USING BIOENERGY FROM LIGNOCELLULOCE BIOMASS

ANALISIS KONSUMSI DAN PENAWARAN ENERGI DAN TREND PENGEMBANGAN BIOENERGI DI INDONESIA