The effects of enzyme loading on the extent of transesterification were determined. Immobilized lipase loading in the range of 3-10 g was conducted in these trans­esterification studies of Jatropha oil with ethanol. 50 mg free lipase corresponds to

2.6 g of immobilized beads in these reactions. Other reaction parameters remained the same as mentioned in the optimization section.

Figure 12.7c shows the effect of immobilized lipase on transesterification of crude J. curcas oil. A maximum yield of 78% was obtained with 5.2 g of immobi­lized lipase. Higher enzyme loading resulted in a decrease in biodiesel yield.

There is an untapped potential of palm lignocellulosic biomass (EFB, palm shell, mesocarp fibre) for power generation—either as biomass to solid (BTS), biomass to liquid (BTL) or biomass to gas (BTG).

Palm lignocellulosic biomass consists of lignin, cellulose, hemicellulose and ash in different chemical compositions (Table 1.3) (Loh et al. 2012) which determine the types of second-generation biofuels to be produced. For example, cellulose and hemi — cellulose can be converted into liquid biofuels (bioethanol, bio-oil, synthetic diesel) whereas lignin as biochar fuel. Lignin is a complex polymer of phenylpropane units, which are cross-linked to each other with a variety of different chemical bonds to provide cell wall mechanical strength. Cellulose is a long chain glucose molecule

linking primarily with p (1-4) glycosidic bond. The presence of hemicelluloses in bundles in the cellulose molecule can enhance the stability of the cell wall. Hemicellulose consists of branched polymers such as xylose, arabinose, galactose and mannose. It also cross-links with lignin creating a complex web of bonds. Cellulose and hemicellulose are made up of a majority of monomer glucose and xylose, respec­tively; thus, these sugars can be extracted for further use (Saka et al. 2008).

As a rule of thumb, an oil palm contains 10% oil and the remaining 90% palm biomass. Based on this, the oil palm industry generates up to 80 million tonnes dry biomass a year. As oil palm biomass has caloric value (Table 1.4) comparable to commercial fossil fuels, their potential use as fuels is tremendous in terms of barrel of oil equivalent derived.

However, most of the oil palm biomass is currently mulched or returned back to the field as biofertiliser to improve soil fertility (MPOB 2010). There are also many other competitive uses (especially for EFB and POME) including fibre processing into mat­tress, furniture-based manufacturing, pulp and paper making, cement manufacturing etc., besides being used for power generation (as boiler fuel) in palm oil mills.

Replanting of palm oil trees (mostly after 25 years of planting) contributes to the generation of huge amount of OPW in the form of palm trunks (OPTs). After replanting, the bole length of felled OPT may range between 7 and 13 m with a diameter of 45-65 cm taken at breast height (Abdul Khalil et al. 2010). After every replanting of palm oil trees throughout year, ~37 million tonnes of OPT is generated in Malaysia alone (Yusoff 2006). However, only about 40% are used for making plywood. The remaining 60% are discarded as OPWs which comprise core logs (50%) and veneers offcuts (10%) (Abdul Khalil et al. 2010). These materials could be utilised as feedstock for biofuel production and other value-added bio-products.

OPT comprises long vascular bundles which are surrounded by parenchyma tis­sues with numerous fibrous strands and vascular bundles. About 53.87% (dry weight) of OPT constitutes extractable fibre bundles, whilst the bark and parenchyma tissues form about 14% and 32% of the dry weight of the OPT, respectively (Abdul Khalil et al. 2010). These cells and tissues are packed with large quantities of holo­cellulose (about 45% cellulose and 25% hemicellulose), lignin (about 18%) and other extractives (about 10%) which can be fractionated, isolated and purified for value-added products. The sugar contents in OPT are about 35-48% glucose, 11-16% xylose, 0.50-0.63% galactose, 1.00-1.37% arabinose, 0.50-0.95% man­nose and 0.20-0.023% rhamnose (Halimahton and Abdul 1990).

Other chemical constituents of OPT include fatty acid (<2%), 3% crude protein, 43.80% carbon, 6.20% hydrogen, 0.44% nitrogen, 42.65% oxygen, 0.09% sulphur and 6.87% ash (all at dry weights). OPT has an average density of 370 kg/m3, moisture content of 55-83% and heating value of 19.26 MJ/kg (Nipattummakula et al. 2012).

Raw materials for fatty acid methyl ester (FAME) synthesis cover from edible and nonedible oils to animal fats and tallows. Recently, microalgae have also attracted researchers’ attention on utilizing them as biodiesel feedstock. The availability of feedstocks for producing biodiesel depends on the geographical locations and agri­cultural laws of the country. Soybean is the major biodiesel feedstock in the United States, canola is the major source in Canada, and rapeseed oil is the main feedstock to produce biodiesel in Europe. Conversely, palm oil and Jatropha are more adapt­able for tropical climate region.

Feedstocks usually consist of a mixture of saturated and unsaturated fatty acid chains. These components have different physical and chemical properties, which may affect the characteristics on the biodiesel. Saturated fatty acid compounds in biodiesel enhance the oxidative stability as double bond presence in the chains of fatty acids leads to autoxidation and causes the biodiesel to deteriorate. On the other hand, unsaturated fatty acids are preferable for biodiesel application at low — temperature surroundings but poor oxidative stability.

Oils derived from crops and plants such as soybean, canola, rapeseed, and cot­tonseed are mostly used as feedstocks for commercial biodiesel production. These raw materials are more preferable than others because the pretreatment step is eliminated as their low FFA content.

However, large-scale production of biodiesel using these feedstocks can cause increased worldwide food and commodity prices. Furthermore, large amount of raw materials required for the production resulted in inadequate supply for food indus­try. The issue about fueling vehicles with crops instead of feeding the community has been around since they are utilizing vegetable oil as the feedstock. Also, there has been growing concerns over the availability of resources and the amount of land required for the plantation. The increasing demand for energy crops may lead to deforestation in order to make more land available for cultivation and plantation purposes.

Fats and tallow obtained from animals offer an economic advantage because they are available at cheaper price than edible crops. This lower-cost source of lipid can improve the economics of biodiesel production. However, the high amount of satu­rated fat limits the application of this type of feedstock, especially in cold climates. In addition, complex processes of animal fats including removing contaminants in animal fat feedstocks (i. e., gums, water) and rendering the animal by-products to a certain standard hindered their utilization as biodiesel feedstock in a larger-scale production.

The use of nonedible sources is becoming widely recognized in an effort to reduce the dependency on vegetable oils. These feedstocks are not suitable for human consumption or food sources, therefore eliminating the problem regarding inadequate food supply. Among raw materials considered as nonedible are castor, waste cooking oil, Jatropha curcas, Pongamia pinnata, and rubber seed. The big­gest hurdle for these feedstocks in commercial biodiesel production is their free fatty acid content, which can affect the transesterification, especially the one involv­ing base catalyst. A two-step process involving esterification of FFA, followed by transesterification of triglycerides into biodiesel, can be applied to overcome the setback. But this feedstock refining step further increases the production costs as a result of extra equipments, additional time, and chemicals.

Microalgae have attracted considerable attention from researches as an alterna­tive nonfood biodiesel feedstock. They commonly double their biomass within 24 h and the oil content can exceed 80% by weight of dry biomass (Chisti 2007). These advantages, coupled with the high lipid content, have made microalgae as the prom­ising feedstock for sustainable biodiesel synthesis. Microalgae also have the benefit of requiring less land area for cultivation compared to other feedstocks if it was to meet half of the US transport fuel needs. The land area required for various crops to meet the demand is shown in Table 9.1. Microalgae with 70% oil in biomass clearly indicate that it is feasible for using them as biodiesel feedstock in terms of land area required and also oil yield.

Nevertheless, scaling up of microalgae cultivation for large-scale production remains a challenge nowadays. Growing microalgae in raceway ponds reduce the operating cost but are vulnerable to contamination by other microorganisms. Photo­bioreactors allow better control of the growing conditions. Moreover, the high capi­tal cost hinders the progress of biodiesel from microalgae industry, especially the

high feedstock cost itself. The price and yield from algal biodiesel production will help to determine how well it will perform in the competitive marketplace.

J. curcas or physic nut belongs to Euphorbiaceae family with around 175 known species. Some of the oil-yielding types are Jatropha pohliana, Jatropha gossypifo — lia, Jatropha multifida, and J. curcas. Among these, J. curcas has attained much significance in several ways. Linnaeus was the first one to name the plant as Jatropha curcas Linnaeus (J. curcas L.). The genus name “Jatropha” is derived from the Greek words jatr’os (doctor) and troph’e (food) which encloses its medicinal uses. The plant is a native of tropical America but now flourishes in many tropical and subtropical parts of the world especially Africa and Asia. The first commercial application of this “wonderful plant” was reported from Lisbon where Jatropha oil, imported from Cape Verde, was used for producing soap and lighting of lamps (Abdulla et al. 2011; Nelson et al. 1996; Linnaeus 1753). Synonyms of J. curcas L. according to Dehgan and Webster (1979) and Schultze-Motel (1986) are Curcas purgans Medik., Ricinus americanus Miller., Castiglionia lobata Ruiz & Pavon., Jatropha edulis Cerv., J. acerifolia Salisb., Ricinus jarak Thunb., Curcas adansoni Endl., Curcas indica A. Rich., Jatropha yucatanensis Briq., and Curcas curcas (L.) Britton & Millsp.

J. curcas L. is a small perennial tree or can also be termed as a large shrub with a normal height of 3-5 m. Under favorable conditions, the tree can attain a height of 8 or 10 m. The plant has a soft wood, articulated growth, straight trunk, and thick branchlets. The branches of J. curcas L. contain latex. The leaves are smooth with 4-6 lobes and measures around 10-15 cm by length and width. The plant develops a tap root with initially four narrow lateral roots. The tap root being deep can hold the soil against landslides whereas the lateral roots help in prevention and control of soil erosion. These roots help the plant to even grow on the rock crevices with less water. The average life expectancy of this plant is around 50 years. Ideal flowering occurs during the rainy season. But J. curcas L. flowers are seen almost throughout the year in humid regions and under irrigated zones of the earth. The flowers on terminal inflorescence are unisexual, monoecious, and greenish yellow in color. Male to female flower ratio ranges from 13:1 to 29:1, and this is seen to decrease as the age of the plant increases. The fruits obtained after pollination are green and ellipsoidal in nature. The black seeds inside contain toxins such as phor — bol esters and trypsin inhibitors making it as nonedible. The decorticated seeds contain 40-60% of oil which can be mainly used for lighting, as lubricant, for mak­ing soaps, and above all mainly for biodiesel production (Divakara et al. 2010; Achten et al. 2008).

Three different fermentation media were used to investigate their effects on yeast growth thus affecting the production of ethanol. From Fig. 13.9, Yeast Peptone Dextrose (YPD) broth gives highest ethanol percentage of 9.58% v/v in fermented medium. It was followed by Yeast Extract Peptone (YP) broth which produced 4.70% v/v of ethanol. Lastly, fermentation in water produced much lower ethanol percentage of 1.27% v/v.

Yeast Peptone Dextrose (YPD) broth was used as the fermentation medium to produce the highest percent of ethanol (9.58% v/v). This is because YPD broth provided a complete medium for yeast cultivation and was the most recommended broth for the rapid growth of yeasts, particularly S. cerevisiae. Yeast Peptone Dextrose (YPD) broth contains 1% (mass/volume) yeast extract, 2% peptone and 2% dextrose (d-glucose). Yeast extract and peptone provide carbon, nitrogen, amino acids, essential minerals, vitamins and trace elements to promote growth while dex­trose is the energy source for yeast growth at the primary state.

Figure 13.10 proved that YPD broth has the highest glucose concentration before fermentation (8.10 mg/mL) because of the presence of addition glucose in the fermentation broth. The large reduction of glucose concentration after fermen­tation (i. e. 6.14 mg/mL) showed that there was high utilisation of glucose by yeast. Eventually, yeast converted the high glucose concentration into more ethanol per­centage. The production of ethanol highly depends on the yeast growth. YPD pro­vided a complete fermentation medium that allowed yeasts to multiply exponentially and grow healthy. As a result, they metabolise and turn available sugar into ethanol actively which result in the highest ethanol percentage in the fermented medium. However, the introduction of glucose in the YPD broth affected the utilisation of the targeted carbohydrate and sugars from seaweed as the source for the ethanol fermentation.

■ After Fermentation

Fig. 13.10 Glucose concentration in different fermentation media before and after fermentation

To improve the utilisation of targeted carbohydrate from seaweed, Yeast Extract Peptone (YP) broth was used as the fermentation medium. This medium has dex­trose removed to allow the use of other carbohydrates. Thus, only targeted carbohy­drate and sugar from seaweed can be utilised by the yeast and turn it into ethanol. Fig. 13.10 showed that the reducing sugar concentration in YP broth before fermen­tation was 4.53 mg/mL, which is the second highest concentration. This reducing sugar solely comes from the extracted and hydrolysed seaweed because no addi­tional glucose was added in YP broth. The reducing sugar concentration in YP broth after fermentation was the lowest (0.99 mg/mL). This showed the effective utilisa­tion of available sugar from the seaweed into the ethanol during the fermentation.

From Fig. 13.9, the fermentation with YP broth gave the second highest ethanol percentage (4.70% v/v) because the addition of yeast extract and peptone promotes faster growth of yeast (Alpha Biosciences Inc. 2010). The yeast extract provides all the amino acids necessary for yeast growth and allows faster growth. Yeast extract supplies vitamin B-complexes, which stimulate the growth of yeasts, while peptone provides carbon, nitrogen, minerals, vitamins, trace ingredients and other essential growth nutrients for yeast (Sherman 1991). Yeasts multiply quickly and produce high percentage of ethanol.

Water was used as the control fermentation medium, and it produced the lowest ethanol percentage which was 1.27% v/v (Fig. 13.9). Yeast, S. cerevisiae, can grow in E. cottonii slurry. However, the yeast growth was very slow. As a result, percent­age of ethanol produced is low. The available sugar from seaweed was not fully utilised and turned into ethanol. As shown in Fig. 13.10, the concentrations of glu­cose before fermentation was 4.19 mg/mL and after fermentation (3.31 mg/mL). The low utilisation of glucose and low conversion into ethanol during the fermenta­tion may be caused by the slow yeast growth in the water medium as there are no additional nutrients and supplements provided for the yeast to grow at a higher rate.

It can also mean that E. cottonii slurry alone was not suitable as the fermentation medium for high ethanol production. This result also means that E. cottonii is not a good candidate for high ethanol production.

POIC Lahad Datu has many strengths and advantages to attract investment which

are described as follows:

• Government backed. Owned and supported by the State Government of Sabah. Strong federal and state government financial support to develop the basic infra­structure, i. e., the industrial land, port, and electricity.

• Availability of raw materials. A lot of palm oil and palm biomass are produced nearby and currently there is very limited value adding.

• Strategic project location. Located at the center of the oil palm growing belt, with a deep (20 m draft) and sheltered harbor, near town center and Lahad Datu sea port and airport.

• Market access. Situated at a strategic location to the Southeast Asian market.

The expansion of the palm oil industry coupled with the high population growth resulting in high demand for pulp (for tissue and papermaking) has ended up in the research for more sustainable OPW conversion methods into these value-added products. Through various processes, pulp has been produced from the fibres of OPF (Wanrosli et al. 2007; Zainuddin et al. 2011), EFB (Martm-Sampedro et al. 2012 ; Jimenez et al. 2009; Rodriguez et al. 2008) and OPT (Sun and Tomkinson 2001). Sun and Tomkinson (2001) have reported that about 93.6% of the total lignin (with a purity of 98.8%) in OPT can be recovered from the supernatants of the black liquor of the OPT fibre after isolation of the polysaccharide degradation.

The appropriate morphological characteristics of OPF (compared to those of wood) such as higher rigidity index (83.16 pm), thick cell wall (3.97 pm), lower lignin content, high fibre diameter (19.6 pm), high lumen width (11.66 pm) and coarseness (0.098 mg/m) make it a good source of pulping material (Mohammad Izzuddin Bin 2008) . The lower lignin content makes it easier to be chemically pulped, whilst the cell wall thickness gives it a sheet of higher bulk (making its sheets not to collapse easily) and lower interfibre bonding potential compared to those of hardwood like aspen (Law and Jiang 2001) and eucalyptus (Alcaide et al. 1990).

EFB can also be chemically pulped to produce high purity unbleached cellulose pulp by water pre-hydrolysis treatment and soda pulping (Wanrosli et al. 2003; Leha et al. 2008). Recently, an effective patented method of producing recycled bleached mechanised pulp (RBMP) from EFB has been developed by 1 Green Enviro Sdn Bhd (a company in Malaysia). This method is capable of producing pulp from EFB at a cost of US$2.70 per metric tonne compared to the cost of producing it from 20% softwood pulp and 80% old corrugating cartonnes (US$307.50 per metric tonne). It has also been reported by the Malaysian Timber Council (MTC) that for every 5 tonnes of EFB produced, about 1 tonne of pulp could be obtained from it.

Reactive distillation (RD) is the process in which chemical reaction and distillation separation are carried out simultaneously within the same apparatus. The conver­sion can be increased far beyond the equilibrium due to the continuous removal of products from the reactive zone. This technique exploits the concept of fractional distillation column, where different products are withdrawn from stages of different temperature. This approach can potentially reduce capital investment and operation costs, especially for the process involving equilibrium reaction such as transesteri­fication. Among the advantages offered by this method are its tendency to eliminate formation of azeotropes in the mixture, simplify the subsequent processing, avoid using excess of reactants to meet stoichiometric feed conditions, and efficient con­trol of the reaction temperature (Estrada-Villagrana et al. 2006).

Reactive distillation method is suitable for homogeneous catalysis of biodiesel production. He et al. (2005) conducted a comprehensive study on biodiesel synthesis from canola oil using a continuous-flow reactive distillation (RD) reactor system. The catalyst was either potassium hydroxide or potassium methoxide (KOCH3). The use of KOCH3 resulted in higher product yield and productivity, and KOH leads to higher formation of soap compared to the other catalyst. The methanol circula­tion modes also influenced the output. Refluxing the methanol back into the column leads to better product yield and productivity but also resulted in higher soap forma­tion. Optimization of operating conditions reached 96.6% yield and 98.3% conver­sion of biodiesel, with only 0.48 wt% of soap produced.

Esterification process based on catalytic reactive distillation was carried out by Kiss et al. (2007) using metal oxides catalysts, such as niobic acid, sulfated zirconia, sulfated titania, and sulfated tin oxide. Based on the esterification of fatty acids, sulfated zirconia was determined as the most active catalyst, coupled with good thermal stability and selectivity of the product. Furthermore, the catalyst does not suffer deactivation due to leaching of sulfate group even when water is present.

Later, biodiesel production under reactive distillation conditions was simulated using AspenTech AspenOne 2004 software. The distillation column has 14 stages. The fatty acid is fed above the reactive zone, while methanol is fed below the reac­tion zone. Lower reflux ratio is essential to shift the reaction equilibrium towards the products. The residence time in the column is about 10 min, which is much lower than conventional processes.

The transesterification of waste cooking oil was done in a reactive distillation column and heteropolyacid, H3PW12O40-6H2O, was used as the catalyst (Noshadi et al. 2012). Response surface methodology (RSM) was applied in the study to find the optimum operating conditions for production of FAME. Increase in inlet feed temperature, total feed flow, and molar ratio of methanol to oil enhanced biodiesel yield. The same trend was also observed with the increased of reboiler duty; how­ever, increasing the reboiler duty from 1.25 to 1.5 kW decreases the FAME yield due to vaporization of methanol in the column. The highest predicted FAME yield from the study can be achieved using total feed flow of 116.23 mol/h, feed tempera­ture (29.9°C), reboiler duty (1.3 kW), and methanol to oil ratio of 67.9:1. The actual FAME yield at optimum conditions did not differ much to the predicted FAME yield, i. e., 93.94% and 93.98%, respectively.

The stability of immobilized hybrid lipase was studied in a number of ways as men­tioned below. The stability study of immobilized lipase is very important before its application in biodiesel production.