**2. Non-edible biomass sources**

### **2.1. Date palm seeds**

The date (*Phoenix dactylifera*) has always played an important role in the economy and social life of the people of arid and semiarid regions of the world. *Phoenix dactylifera* (date or date palm), a flowering plant species in the palm family Arecaceae, is one of the member of the genus *Phoenix*, widely cultivated for its edible fruit. Dates have been a staple diet in the Middle East for thousands of years. Date seeds, considered as waste product, are either discarded or used as fodder for domestic farm animals. Egypt is considered the first rank in the production of date as shown in Table 1. The total world production of date fruits was about 6.64 million tons in 2007 [1], with Egypt, Iran, Kingdom of Saudi Arabia, UAE and Pakistan being the main producing countries. Habib and Ibrahim [2] found that, the relative percentage of date seeds to the date fruits ranges 6.10%–11.47%. The same author also estimated the annual world production of date seeds at about 697,000 tons in 2007. Date seeds are commonly considered as a waste product (Figure 1) that is either discarded or used in animal feed. However, date seeds have been shown to possess extractable high value added components [3]. Date seeds, which are low cost agriculture by-products, can be used for production of activated carbon.

**Figure 1: Date palm seeds pictures. Figure 1.** Date palm seeds pictures.

production of fatty acid methyl esters (biodiesel).

In an attempt to make use of this costless date seeds for biodiesel production, Shanab et al [4] found that the oil content (extracted with petroleum ether) in the four date seed cultivars ranged between 3.31% and 4.48% as recorded in Table 2. In an attempt to make use of this costless date seeds for biodiesel production, Shanab et al [4] found that the oil content (extracted with petroleum ether) in the four date seed cultivars ranged between 3.31% and 4.48% as recorded in Table 2.

Ramly showed the highest oil content (4.48%) followed in descending order by Amhat (3.88%) Ramly showed the highest oil content (4.48%) followed in descending order by Amhat (3.88%) then Sewy (3.34%) and Haiany (3.31%).

then Sewy (3.34%) and Haiany (3.31%). It is evident from these results and previous investigations that, date seeds do not provide high It is evident from these results and previous investigations that, date seeds do not provide high yield of oil [2], but the oil may serve as a potential source of some important phytochemicals [3].

yield of oil [2], but the oil may serve as a potential source of some important phytochemicals [3]. Transesterification of the extracted date seed oils by Methanol/KOH mixture led to the Transesterification of the extracted date seed oils by Methanol/KOH mixture led to the production of fatty acid methyl esters (biodiesel).

**Iodine value** (IV) is a measure of unsaturation degree. The obtained results revealed that date seed cultivars showed different iodine values (mg I2/g), which ranged between 90.4 mg/g in

These variable contents may be due to high content of saturated fatty acids in their oils, which

Shalaby and El-Gendy [5] reported that waste cooking oil and its methyl esters have low iodine values (~ 62, 60 mg I2/100g oil). Also, JUS [6] illustrated that, methyl esters used as biodiesel fuel must have an iodine value less than 120 mg I2/100g of the oil sample (JUS EN 14214). This means that the iodine values of the produced biodiesel from date seed oils in this study (75.3–

**Physico-chemical properties of produced biodiesel from date palm seeds** 

Sewy, 88.5 in Amhat, 86.3 in Haiany and 75.3 mg/g in Ramly (Table 3).

was confirmed by the GC analysis of the four date seed cultivars.

5

### *2.1.1. Physico-chemical properties of produced biodiesel from date palm seeds*

**2. Non-edible biomass sources**

**Figure 1: Date palm seeds pictures.** 

**Figure 1.** Date palm seeds pictures.

then Sewy (3.34%) and Haiany (3.31%).

then Sewy (3.34%) and Haiany (3.31%).

between 3.31% and 4.48% as recorded in Table 2.

ranged between 3.31% and 4.48% as recorded in Table 2.

production of fatty acid methyl esters (biodiesel).

production of fatty acid methyl esters (biodiesel).

The date (*Phoenix dactylifera*) has always played an important role in the economy and social life of the people of arid and semiarid regions of the world. *Phoenix dactylifera* (date or date palm), a flowering plant species in the palm family Arecaceae, is one of the member of the genus *Phoenix*, widely cultivated for its edible fruit. Dates have been a staple diet in the Middle East for thousands of years. Date seeds, considered as waste product, are either discarded or used as fodder for domestic farm animals. Egypt is considered the first rank in the production of date as shown in Table 1. The total world production of date fruits was about 6.64 million tons in 2007 [1], with Egypt, Iran, Kingdom of Saudi Arabia, UAE and Pakistan being the main producing countries. Habib and Ibrahim [2] found that, the relative percentage of date seeds to the date fruits ranges 6.10%–11.47%. The same author also estimated the annual world production of date seeds at about 697,000 tons in 2007. Date seeds are commonly considered as a waste product (Figure 1) that is either discarded or used in animal feed. However, date seeds have been shown to possess extractable high value added components [3]. Date seeds, which are low cost agriculture by-products, can be used for production of activated carbon.

5

In an attempt to make use of this costless date seeds for biodiesel production, Shanab et al [4] found that the oil content (extracted with petroleum ether) in the four date seed cultivars ranged

In an attempt to make use of this costless date seeds for biodiesel production, Shanab et al [4] found that the oil content (extracted with petroleum ether) in the four date seed cultivars

Ramly showed the highest oil content (4.48%) followed in descending order by Amhat (3.88%)

Ramly showed the highest oil content (4.48%) followed in descending order by Amhat (3.88%)

It is evident from these results and previous investigations that, date seeds do not provide high yield of oil [2], but the oil may serve as a potential source of some important phytochemicals [3]. Transesterification of the extracted date seed oils by Methanol/KOH mixture led to the

It is evident from these results and previous investigations that, date seeds do not provide high yield of oil [2], but the oil may serve as a potential source of some important phytochemicals [3]. Transesterification of the extracted date seed oils by Methanol/KOH mixture led to the

**Iodine value** (IV) is a measure of unsaturation degree. The obtained results revealed that date seed cultivars showed different iodine values (mg I2/g), which ranged between 90.4 mg/g in

These variable contents may be due to high content of saturated fatty acids in their oils, which

Shalaby and El-Gendy [5] reported that waste cooking oil and its methyl esters have low iodine values (~ 62, 60 mg I2/100g oil). Also, JUS [6] illustrated that, methyl esters used as biodiesel fuel must have an iodine value less than 120 mg I2/100g of the oil sample (JUS EN 14214). This means that the iodine values of the produced biodiesel from date seed oils in this study (75.3–

**Physico-chemical properties of produced biodiesel from date palm seeds** 

Sewy, 88.5 in Amhat, 86.3 in Haiany and 75.3 mg/g in Ramly (Table 3).

was confirmed by the GC analysis of the four date seed cultivars.

**2.1. Date palm seeds**

4 Biofuels - Status and Perspective

**Iodine value** (IV) is a measure of unsaturation degree. The obtained results revealed that date seed cultivars showed different iodine values (mg I2/g), which ranged between 90.4 mg/g in Sewy, 88.5 in Amhat, 86.3 in Haiany and 75.3 mg/g in Ramly (Table 3).

These variable contents may be due to high content of saturated fatty acids in their oils, which was confirmed by the GC analysis of the four date seed cultivars.

Shalaby and El-Gendy [5] reported that waste cooking oil and its methyl esters have low iodine values (~ 62, 60 mg I2/100g oil). Also, JUS [6] illustrated that, methyl esters used as biodiesel fuel must have an iodine value less than 120 mg I2/100g of the oil sample (JUS EN 14214). This means that the iodine values of the produced biodiesel from date seed oils in this study (75.3–90.4 mg I2/g) as well as from *Phoenix canariensis* seed oil (76.66 mg I2/g) were due to the high contents of saturated fatty acids leading to low or even no oxida‐ tion tendency in these oils [7].

The low Acid values (AV) recorded in the four cultivars of date seed oils ranged 0.5–0.92 mgKOH/g, and these results indicated that these oils can be stored for longer periods without deterioration, which seems in conformity with the results reported by Ojeh [8].

Acid value of biodiesel was shown to be higher than that of standard petrodiesel, but it meets the standard limits of EN 14215 and D-6751, indicating that the free fatty acids content will not cause operational problems such as corrosion and pump plugging caused by corrosion and deposit formation.

Variable saponification values (SV) in the studied four date seed cultivars (185.4–202.3 mgKOH/g) of the *P. canariensis* seed oil (191.28) indicated the presence of low molecular weight triacylglycerols, which are in conformity with those reported by Eskin *et al*., [9] and Oomah *et al*., [10] who declared that their saponification values are similar to values of canola oil and raspberry seed oil.

More or less similar higher heating values (HHV, Table 4) of the produced fatty acid methyl esters (39.84 kg/g–40.50 kg/g) indicated that they have nearly similar stability values due to their low polyunsaturated fatty acids contents in their oils, which were clearly observed in the GC analysis of fatty acid methyl esters (Table 5).

Infrared spectrum (IR) of the produced biodiesel showed the presence of ester group (-C-O-) at bands 1027, 1165 and 1745, as well as the absence of the hydroxyl peak, which can be correlated to the transesterification process of date seed oil (Figure 2).

These results were concomitant with those reported by Shalaby and El-Gendy (2012) on waste cooking oil methyl ester.

Fatty acid composition of the esterified products using gas chromatography (GC) revealed the presence of eight saturated fatty acids (C8:0–C18:0) in the three date seed cultivars: Amhat, Ramly and Haiany, while cultivar Sewy has only seven saturated fatty acids as recorded in Table 5.

The highest percentage of saturated fatty acids was shown in Amhat cultivar (79.517%) followed in descending order by those of Haiany (68.135%), Sewy (45.764%) and Ramly (20.986%).

The fatty acids caprylic (C8:0) and capric (C10:0) constituted the largest percentage of saturated fatty acids in the studied date seeds. Ramly cultivar was the only date seed containing Arachidic fatty acid (C20:0) of 0.441%.

The recorded unsaturated fatty acids were oleic (C18:1) and Linoleic (C18:2), which were present in variable relative percentages in only three of the four date seed cultivars (24.64% in Ramly to 0.573% in Sewy), while linoleic acid was absent in Amhat cultivar (Oleic represented by 1.88%).

Ramly recorded the most pronounced content of unsaturated fatty acids (20.99% Oleic + 3.65% Linoleic), and the least percentage of saturated fatty acids (20.986%).

Our results go parallel with those published by Nehdi *et al*. [11] on date palm seeds and seed oils.

Yong and Salimon [12] reported that liquid oils with high oleic fatty acid content (as Ramly oil) normally have good flavor and frying stability.

Oleic acid is important in nervous cell construction and can be changed in the organism into a set of compounds close to prostaglandin, which have an important role at the vessel level and for blood coagulation [13]. So, Ramly can be of importance in this concern.

**Figure 2.** Infrared spectrum of Fatty acid methyl ester (FAME) of date palm seed.

A Review of Selected Non-Edible Biomass Sources as Feedstock for Biodiesel Production http://dx.doi.org/10.5772/59178 7


**Table 1.** Total date production by different countries and continents [1].

The highest percentage of saturated fatty acids was shown in Amhat cultivar (79.517%) followed in descending order by those of Haiany (68.135%), Sewy (45.764%) and Ramly

The fatty acids caprylic (C8:0) and capric (C10:0) constituted the largest percentage of saturated fatty acids in the studied date seeds. Ramly cultivar was the only date seed containing

The recorded unsaturated fatty acids were oleic (C18:1) and Linoleic (C18:2), which were present in variable relative percentages in only three of the four date seed cultivars (24.64% in Ramly to 0.573% in Sewy), while linoleic acid was absent in Amhat cultivar (Oleic represented by

Ramly recorded the most pronounced content of unsaturated fatty acids (20.99% Oleic + 3.65%

Our results go parallel with those published by Nehdi *et al*. [11] on date palm seeds and seed

Yong and Salimon [12] reported that liquid oils with high oleic fatty acid content (as Ramly

Oleic acid is important in nervous cell construction and can be changed in the organism into a set of compounds close to prostaglandin, which have an important role at the vessel level

and for blood coagulation [13]. So, Ramly can be of importance in this concern.

**Figure 2.** Infrared spectrum of Fatty acid methyl ester (FAME) of date palm seed.

Linoleic), and the least percentage of saturated fatty acids (20.986%).

oil) normally have good flavor and frying stability.

(20.986%).

6 Biofuels - Status and Perspective

1.88%).

oils.

Arachidic fatty acid (C20:0) of 0.441%.


**Table 2.** Oil contents, Biodiesel and glycerol (%) in different date seed cultivars [4].


**Table 3.** Some chemical properties of methyl esters of date seed [4].

#### 8 Biofuels - Status and Perspective


**Table 4.** Higher heating value (HHV) and cetane number (CN) of fatty acid methyl esters of date seed cultivars [4].


\*Rt : Retention time; SFA: Saturated fatty acids; USFA: Unsaturated fatty acids

**Table 5.** Fatty acids content in different commercial date seeds cultivars [4].

### **2.2. Non-edible plants (e.g., Jatropha)**

Jatropha is a genus of flowering plants in the spurge family, Euphorbiaceae. Jatropha is a drought-resistant perennial, growing well in marginal/poor soil and considered as one of the best candidates for future biodiesel production. Jatropha the wonder plant produces seeds (Figure 3) with an oil content of around 27%–40%. The oil can be combusted as fuel without being refined. It burns with clear smoke-free flame, tested successfully as fuel for simple diesel engine. Oil contains also insecticide. It can also be used as a bio-pesticide and for medicinal purposes. It is found to be growing in many parts of the country, is rugged in nature, can survive with minimum inputs, and is easy to propagate, and these growth conditions give this plant the big chance for selection as biofuel sources. inputs, and is easy to propagate, and these growth conditions give this plant the big chance for selection as biofuel sources.

**Figure 3.** Pictures of Jatropha tree and seeds.

**Species HHV (Kj/g) CN**

**Table 4.** Higher heating value (HHV) and cetane number (CN) of fatty acid methyl esters of date seed cultivars [4].

**C8:0 7.3** 50.77 - - 47.35 **C10: 0 11.16** 28.37 - 57.06 26.88 **C11:0 13.36** 5.44 1.07 - 8.9 **C12:0 15.51** 2.77 1.55 9.69 4.82 **C13:0 17.51** 5.93 22.9 14.9 5.9 **C14:0 19.61** 2.62 4.52 10.38 4.72 **C15:0 21.45** 0.97 4.61 3.08 2.7 **C16:0 23.27** 0.79 7.63 2.48 0.39 **C17:0 24.9** - 1.50 1.10 - **C18:0 26.63** - 0.85 - 0.37 **C18:1 27.16** 2.31 45.9 1.04 1.22 **C18:2 28.06** - 7.98 0.19 0.48 **C18:3 29.28** - - - - **C20:0 29.76** - 0.96 - -

**SFA** 97.69 46.12 98.77 98.3 **USFA** 2.31 53.88 1.23 1.7 **SFA/USFA ratio** 42.3/1 0.85/1 80.3/1 57.8/1

Jatropha is a genus of flowering plants in the spurge family, Euphorbiaceae. Jatropha is a drought-resistant perennial, growing well in marginal/poor soil and considered as one of the best candidates for future biodiesel production. Jatropha the wonder plant produces seeds (Figure 3) with an oil content of around 27%–40%. The oil can be combusted as fuel without

: Retention time; SFA: Saturated fatty acids; USFA: Unsaturated fatty acids

**Table 5.** Fatty acids content in different commercial date seeds cultivars [4].

**2.2. Non-edible plants (e.g., Jatropha)**

**Relative % of Fatty acids in different Date seeds Amhat Ramly Sewy Haiany**

**Amhat** 40.50 60.52 **Ramly** 40.14 55.42 **Siwy** 40.18 57.03 **Haiany** 39.84 54.61

**Fatty acids RT**

8 Biofuels - Status and Perspective

\*Rt

**Figure 4.** Jatropha oil extraction method. (http://www.aumkiipure.com/oil-extraction.html)

11 The suitability of a particular oil type from Jatropha species depends on its chemical and physical properties and the plant origin. The fatty acids composition is very important for

**Figure 5.** Jatropha biodiesel extraction methods (http://www.aumkiipure.com/oil-extraction.html).

physical and chemical properties of produced biodiesel. The fatty acid composition of jatropha oil has been reported in Table 6. The Gas Chromatographic analysis of the fatty acid compo‐ sitions of the oils showed oleic acid to be significantly higher (p < 0.05) than linoleic, palmitic, stearic and myristic acids.

Also, medically, it is used for different diseases due to its antioxidant, anticancer and antibac‐ terial activities. These activities may be due to the presence of various active ingredients including phenolic compounds and flavonoid groups.


**Table 6.** Fatty acid profile of jatropha oil

Oils extracted (Figure 4) from jatropha seeds as one of non-edible crops are potential feed‐ stock's for biodiesel production. From all non-edible oil plants, jatropha, karanja, mahua and castor oils are the most often used in biodiesel production (Figure 5). In many countries, edible oils are not produced in enough amounts to meet the nutrition requirements for human use and must be imported. Hence, the price of biodiesel produced from edible oils is much higher than that of petrodiesel. Therefore, non-edible oils from plants like jatropha, karanja, neem, mahua and other plants (Figure 6) are the only possibility for biodiesel production.

**Figure 6.** Selected non-edible fruits bearing plants.

physical and chemical properties of produced biodiesel. The fatty acid composition of jatropha oil has been reported in Table 6. The Gas Chromatographic analysis of the fatty acid compo‐ sitions of the oils showed oleic acid to be significantly higher (p < 0.05) than linoleic, palmitic,

**Figure 5.** Jatropha biodiesel extraction methods (http://www.aumkiipure.com/oil-extraction.html).

Also, medically, it is used for different diseases due to its antioxidant, anticancer and antibac‐ terial activities. These activities may be due to the presence of various active ingredients

**Fatty acids Formula Structure Wt%** Myristic C12H28O2 14:0 0.5-1.4 Palmitic C16H32O2 16:0 12-7.0 Stearic C18H36O2 18:0 5.0-9.7 Oleic C18H34O2 18:1 37-63 linoleic C18H32O2 18:2 19-41

Oils extracted (Figure 4) from jatropha seeds as one of non-edible crops are potential feed‐ stock's for biodiesel production. From all non-edible oil plants, jatropha, karanja, mahua and castor oils are the most often used in biodiesel production (Figure 5). In many countries, edible

stearic and myristic acids.

10 Biofuels - Status and Perspective

**Table 6.** Fatty acid profile of jatropha oil

including phenolic compounds and flavonoid groups.

### **2.3. Agricultural residues as biomass sources**

From the different economy sectors, there is different industrial, agricultural, forestry, municipal residues. Of these residues (Figure 7), agricultural residues produced in large quantities every year. Wheat, Rice, sugar cane, maize, soybeans and groundnuts are just a few examples of crops that generate considerable amounts of residues. These biomass residues are an important source of energy both for domestic as well as industrial purposes. Juninger et al. [14] mentioned that, if only all process-based agricultural residues alone would be used, they could contribute between 25% and 40% of the total primary commercial energy production in various Southeast Asian countries

Until now, bagasse and rice husk are considered the two major biomass resources being used for power generation (approx. 15–17 and 5.0 Mio t/year, respectively). Moreover, forest residues and wood wastes represent a large potential resource for energy production; the primary advantage of using forest residues for power generation is that an existing collection of infrastructure is already set up to harvest wood in many areas.

**Figure 7.** The major expected biomass sources for biofuel production (http://i2.wp.com/www.bioenergyconsult.com/ wpontent/uploads/2012/04/biomass\_resources1.jpg).

### **2.4. Waste cooking oils**

Recycling of waste cooking oils is increasingly being carried out to produce biofuel (Figures 8 and 9). Opportunities for businesses and consumers to recycle used cooking oil ("yellow grease") have increased due to the price of waste cooking oils (WCO), which is 2–3 times cheaper than virgin vegetable oils. A significant advantage is that, biofuels derived from waste cooking oil typically burn clean, have low carbon content and do not produce carbon monox‐ ide. This helps communities to reduce their carbon footprints (there was on average of a decrease of 14% for CO2, 17.1% for CO and 22.5% for smoke density when using biodiesel from recycling of waste cooking oils.). The recycling of cooking oil also provides a form of revenue for restaurants, which are sometimes compensated by cooking oil recyclers for their used deep fryer oil. However, the optimum conditions for biodiesel production (methanol/oils ratio and concentration of catalyst) are inconsistent. They strongly depend on the properties of WCO.

The processes of such oils and fats pose a significant challenge because of their disposal problems and possible contamination of the water and other resources.

Using Gc analysis of biodiesel produced from waste cooking oil, 60% of the fatty acids were found to be monounsaturated (C18:1). Polyunsaturated fatty acids were found to be approx‐ imately 26% (C18:2, C18:3). However, 8% fatty acids were saturated. (Palmitic acid and stearic acid were the major saturated fatty acids) as reported by Chhetri et al. [15].

**Figure 8.** Biodiesel production from waste cooking oils.

**Figure 7.** The major expected biomass sources for biofuel production (http://i2.wp.com/www.bioenergyconsult.com/

Recycling of waste cooking oils is increasingly being carried out to produce biofuel (Figures 8 and 9). Opportunities for businesses and consumers to recycle used cooking oil ("yellow grease") have increased due to the price of waste cooking oils (WCO), which is 2–3 times cheaper than virgin vegetable oils. A significant advantage is that, biofuels derived from waste cooking oil typically burn clean, have low carbon content and do not produce carbon monox‐ ide. This helps communities to reduce their carbon footprints (there was on average of a decrease of 14% for CO2, 17.1% for CO and 22.5% for smoke density when using biodiesel from recycling of waste cooking oils.). The recycling of cooking oil also provides a form of revenue for restaurants, which are sometimes compensated by cooking oil recyclers for their used deep fryer oil. However, the optimum conditions for biodiesel production (methanol/oils ratio and concentration of catalyst) are inconsistent. They strongly depend on the properties

The processes of such oils and fats pose a significant challenge because of their disposal

problems and possible contamination of the water and other resources.

wpontent/uploads/2012/04/biomass\_resources1.jpg).

**2.4. Waste cooking oils**

12 Biofuels - Status and Perspective

of WCO.

The chemical properties of waste cooking oil and produced biodiesel are very important factors for using the biodiesel in industrial sector. From these properties; Acid value (AV) refers to the content of free acids in the sample, which have an influence on fuel aging. It is measured in terms of the quantity of KOH required to neutralise sample. Predojevic [7]reported that, the base catalyzed reaction is reported to be very sensitive to the content of free fatty acids, which should not exceed a certain limit recommended to avoid deactivation of the catalyst, formation of soaps and emulsion. Sharma *et al*. [16] found that, AV of the feedstock for alkaline transes‐ terification has to be reduced to less than 2 mg KOH/g (1%), while only few examples of transesterification with feedstock acid value of up to 4.0 mg KOH/g (2%) were found. The authors also reported that, the limit of free fatty acids is a bit relaxed and the value a little beyond 1% (i.e. 2 mg KOH/g) when using waste cooking oil as feedstock for biodiesel pro‐ duction. In addition, the acid value of WCO feed stocks was 5 mg KOH/g oil. From this result it could be concluded that the used WCO had values above the recommended (2 mg KOH/g). However, this value did not turn out to be limiting for the efficiency of the applied two-stage process, as it will be discussed along with the obtained product yield and purity later. Furthermore, The AV of the produced Fatty acids methyl ester (FAME) was 0.48 mg KOH/g oil. The recorded acid value of the produced biodiesel is higher than that of standard petro‐ diesel, but it meets the standard limits of biodiesel EN14215 and biodiesel D-6751, indicating that the free fatty acid content will not cause operational problems, such as corrosion and pump plugging, caused by corrosion and deposit formation [5].

**Figure 9.** The processes for biodiesel and glycerin production from waste cooking oils

### **2.5. Algae (especially microalgae)**

Microalgae are photosynthetic microorganisms that are able to rapidly generate biomass from solar energy, CO2 and nutrients in bodies of water. This biomass consists of important primary metabolites such as sugars, oils and lipids, for which process path-ways exist for the produc‐ tion of high-value products including human and animal feed supplements, transport fuels, industrial chemicals and pharmaceuticals. Algae are capable of producing 30 times the amount of oils and lipids per unit area of land as compared to terrestrial oilseed crops (microalgae are capable of producing much higher amount oil per unit area of land, compared to many terrestrial oilseed crops, such as soybean, coconut and palm [17].

Many microalgae are exceedingly rich in oil, which can be converted to biodiesel using existing technology (Figure 10). More than 50% of their biomass as lipids, sometimes even up to 80%, and oil levels of 20%–50% are quite common [18]. Lipids production and biodiesel extraction from algae depend on algal species and extraction solvent system[19].

A Review of Selected Non-Edible Biomass Sources as Feedstock for Biodiesel Production http://dx.doi.org/10.5772/59178 15

**Figure 10.** Process for conversion of algal oils to biodiesel. (http://refuelingthefuture.yolasite.com/third-generation-bio‐ fuels.php)

#### *2.5.1. The benefits of Algae over previous generations*


Furthermore, The AV of the produced Fatty acids methyl ester (FAME) was 0.48 mg KOH/g oil. The recorded acid value of the produced biodiesel is higher than that of standard petro‐ diesel, but it meets the standard limits of biodiesel EN14215 and biodiesel D-6751, indicating that the free fatty acid content will not cause operational problems, such as corrosion and pump

plugging, caused by corrosion and deposit formation [5].

14 Biofuels - Status and Perspective

**Figure 9.** The processes for biodiesel and glycerin production from waste cooking oils

terrestrial oilseed crops, such as soybean, coconut and palm [17].

from algae depend on algal species and extraction solvent system[19].

Microalgae are photosynthetic microorganisms that are able to rapidly generate biomass from solar energy, CO2 and nutrients in bodies of water. This biomass consists of important primary metabolites such as sugars, oils and lipids, for which process path-ways exist for the produc‐ tion of high-value products including human and animal feed supplements, transport fuels, industrial chemicals and pharmaceuticals. Algae are capable of producing 30 times the amount of oils and lipids per unit area of land as compared to terrestrial oilseed crops (microalgae are capable of producing much higher amount oil per unit area of land, compared to many

Many microalgae are exceedingly rich in oil, which can be converted to biodiesel using existing technology (Figure 10). More than 50% of their biomass as lipids, sometimes even up to 80%, and oil levels of 20%–50% are quite common [18]. Lipids production and biodiesel extraction

**2.5. Algae (especially microalgae)**


**•** Algae can be cultivated in different wastewater sources. This can be used as an alternative water treatment method. This method is cost effective. It requires a low amount of energy. It reduces sludge, and in the end, it cleans the water and produces algae for biofuel use.

Results in Table 7 show the lipid amounts extracted from eight algal species (5 macro and 3 microalgae) by the two extraction methods described in the experimental section. The red macroalga *Jania rubens* produced 2.8% lipid when extracted using hexane: ether (1:1, v/v) system whereas the recovery was doubled (4.4%) using the extraction system based on chloroform / methanol (2:1, v/v). No significant difference in the total lipid content was obtained from the red algae *Galaxaura* and *Gelidium* using both systems for extraction (2.4, 3.1 and 2.5, 3.0, respectively). The red seaweed *Asparagopsistaxiformis* and the green *Ulva* produced 1.2-fold increase in extracted lipid percentage and the brown macroalga *Colpomenia sinuosa*, produced a 1.52-fold increase in lipids when extracted by chloroform / methanol (2:1, v/v) system, as illustrated clearly in Tables 1 and 2. Moreover, the microalga *Dictyochloropsis splendida* showed 2.4 % of total lipid when extracted with hexane / ether (1:1, v/v) system, but on using chloroform/methanol (2:1, v/v) as extraction mixture, the percentage of total lipids increased 5.2 times to reach 12.5 % showing at the same time the highest biodiesel production (8.75 %) of the eight algal species used in this investigation. The cyanbacterium *Spirulina platensis* produced a 3-fold increase in lipid content using the chloroform/methanol-based method (Tables 8 and 9).


A Review of Selected Non-Edible Biomass Sources as Feedstock for Biodiesel Production http://dx.doi.org/10.5772/59178 17


**•** Algae can be cultivated in different wastewater sources. This can be used as an alternative water treatment method. This method is cost effective. It requires a low amount of energy. It reduces sludge, and in the end, it cleans the water and produces algae for biofuel use.

Results in Table 7 show the lipid amounts extracted from eight algal species (5 macro and 3 microalgae) by the two extraction methods described in the experimental section. The red macroalga *Jania rubens* produced 2.8% lipid when extracted using hexane: ether (1:1, v/v) system whereas the recovery was doubled (4.4%) using the extraction system based on chloroform / methanol (2:1, v/v). No significant difference in the total lipid content was obtained from the red algae *Galaxaura* and *Gelidium* using both systems for extraction (2.4, 3.1 and 2.5, 3.0, respectively). The red seaweed *Asparagopsistaxiformis* and the green *Ulva* produced 1.2-fold increase in extracted lipid percentage and the brown macroalga *Colpomenia sinuosa*, produced a 1.52-fold increase in lipids when extracted by chloroform / methanol (2:1, v/v) system, as illustrated clearly in Tables 1 and 2. Moreover, the microalga *Dictyochloropsis splendida* showed 2.4 % of total lipid when extracted with hexane / ether (1:1, v/v) system, but on using chloroform/methanol (2:1, v/v) as extraction mixture, the percentage of total lipids increased 5.2 times to reach 12.5 % showing at the same time the highest biodiesel production (8.75 %) of the eight algal species used in this investigation. The cyanbacterium *Spirulina platensis* produced a 3-fold increase in lipid content using the chloroform/methanol-based

*Jania rubens* 4.4±0.12 2.8±0.04

*Galaxaura oblongata* 2.5±0.09 2.4±0.01

*Gelidium latifolium* 3.0±0.0 3.1±0.02

**Chloroform/ methanol (2:1, v/v)**

**Hexane/ether (1:1, v/v)**

method (Tables 8 and 9).

16 Biofuels - Status and Perspective

**Algal species Algal pictures**

Each value is presented as mean of triplet treatments, LSD: Least different significantly at P ≤ 0.05 according to Duncan's multiple range test

**Table 7.** Comparison between lipid percentages (%) produced by eight algal species using hexane/ether (1:1, v/v) and chloroform/methanol (2:1, v/v) extraction systems [21].

The obtained results illustrated in Table 8 revealed that the solvent mixture hexane/ether were not the most suitable system for lipid biodiesel extraction from algae because these solvents were unable to extract polar lipids. On the contrary chloroform/methanol system extracted greater percentage of lipid (non-polar and polar lipids) and gave place to higher biodiesel yields by transesterification. The lowest biodiesel production was observed in the red seaweed *J. rubens* (0.25%) followed in ascending order by *Gelidium latifolium* (1.3%), *Galaxaura oblonga‐ ta* (2.06%) and A. taxiformis (3.64%). While the green macroalga Ulva lactuca and the brown seaweed Colpomenia sinuosa produced comparable biodiesel percentages (3.8 and 3.1%, respectively), the greatest yield of biodiesel was achieved by the green microalgae *D. splen‐ dida* (8.75%) followed in descending order by the cyanbacterium *S. platensis* (7.5%) as illustrated in Table 2. Using chloroform/methanol (2:1, v/v) solvent system, we are able to produce not only biodiesel in large percentage but also a sediment containing glycerin and pigments. The produced biodiesel have slightly alkaline pH values ranging 7.5–8.5 in all preparations. Our results concerning the green microalga *D. splendida* (produced 12.5% lipids) agreed with those obtained by Hossain and Salleh [20] who reported that the green filamentous alga Oedogoni‐ um sp produced higher lipid.


Each value is presented as mean of triplet treatments, LSD: Least different significantly at P ≤ 0.05 according to Duncan's multiple range test.

**Table 8.** Total lipid, biodiesel, sediments percentage and biodiesel colour of different algal species using the extraction solvent system Chloroform/methanol (2:1, v/v) (Afify et al., 2010).

### **3. Conclusion**

From this chapter we conclude that non-edible biomass can be used as a suitable and cheap feedstock for producing biodiesel. Most of non-edible biomass has a considerable amount of low-chain fatty acids, which gives special features to biodiesel. The most important advantages of the current biomass are production of biodiesel with high cetane number, low viscosity. These factors can increase engine's output and decrease pollution compared with other biodiesel fuels. The present experimental results support that methyl ester of non-edible biomass can be successfully used as a biodiesel in the internal combustion engine.
