*5.1.2.1.5 Neem (*Azadirachta indica*)*

Neem (*Azadirachta indica)* tree belongs toMeliaceae family and is a multipurpose evergreen tree which can be grown in almost all kind of soils such as saline, clay,

**Figure 19.** *Karanja (*Pongamia Pinnata*) [93].* *Feasibility of Biodiesel Production in Pakistan DOI: http://dx.doi.org/10.5772/intechopen.101967*

**Figure 20.** *Neem (*Azadirachta indica*).*

alkaline, shallow soils, stony, dry, and even on solid having high calcareous soil. Neem is native to Pakistan, India, Srilanka, Malaysia, Burma, Japan, Indonesia and tropical regions of Australia. It can survive in arid, semi-arid climate with maximum temperature of 49°C and rainfall as low as 250 mm. The seeds of the neem contain 20–50 wt% oil of green to brown colored. In Pakistan neem plant is widely spread in Khyber Pakhtunkhwa, Punjab and Sindh. These trees were planted as part of a project initiated by the Sindh Government in 2008, in response to the Ex-President of Pakistan Asif Ali Zardari's directives to encourage the planting of Neem trees in the province. The Sindh government has set aside Rs.7 billion to plant 10,000 Neem trees on both sides of the National Highway and the Superhighway [96].

Muthu et al. [97] produced the neem methyl ester from the neem oil in the presence of catalysts by two steps process of esterfication and Transesterification. Sulfated Zirconia was used as solid acid catalyst for esterfication, while alkali catalyst i.e., KOH was used for Transesterification. Optimum conversion of free fatty acid was achieved with 1 wt% of sulfated zirconia (acid) catalyst, at 65°C temperature, 9:1 methanol/oil ratio and 2 h reaction time. The acid value of the raw oil was reduced by 94% (24.76 mg KOH/g) which show the successful conversion. The authors noted that when the pretreated oil was transesterified in the presence of KOH, 95% conversion efficiency was achieved (**Figure 20**).

## **5.2 Microalgae for biodiesel production**

Microalgae are eukaryotic or prokaryotic photosynthetic micro-organism that can grow rapidly and live in harsh conditions due to their unicellular or simple multicellular structure [98]. Examples of eukaryotic micro-organisms are green algae i.e., chlorophytaand diatoms i.e., bacillariophyta and prokaryotic micro-organisms are cyanobacteria. Microalgae are present in all existing ecosystem of the earth, not only in aquatic but also terrestrial ecosystem that lives in a wide range of environmental conditions [99]. Interestingly, it is observed in small ponds and ditches in the villages and towns become fully green within a week during the rainy season in Pakistan. Although in Pakistan, the cultivation of oleaginous microalgae is in its infancy, however several species of algae are reported in the literature that can further process or cultivated for the production of oil [100]. Microalgae can provide feedstock for several types of renewable fuels such as methane, biodiesel, ethanol and hydrogen. Biodiesel produced from algae contains no sulfur, reduce emissions of particulate matter, hydrocarbons, CO and SOx. However, NOx emissions may be higher in some types of engine.

Furthermore, a Pakistani researcher at Japan's Mie University claims that the country could benefit from using its 27–28 million acre saline lands for algal farming, which would create jobs and benefit the rural community [101]. Four algae strains suitable for cultivation in Pakistan's deserts have been identified by other researchers. Other researchers have identified four strains of algae that are suitable for cultivation in Pakistan's deserts and produce acceptable lipid yields, i.e. 40% by weight *Haematococcus pluvialis, Microcoleus vaginatus, Chlamydomona sperigranulata*, *Synechocystis* [102]*.*

To produce biodiesel, researchers at the National University of Sciences and Technology (NUST) cultivated Chlorella vulgaris in a closed photo-bioreactor (20 L) in a controlled environment and characterized its properties. At 5000 and 9000 psi and 50 and 80°C, the highest biodiesel yield (more than 99%) was achieved. The biodiesel produced was found to be of ASTM D6751 quality [102].

#### **5.3 Waste cooking oil as feedstock of biodiesel**

The term waste cooking oil (WCO) refers to vegetable oil that has been used in production of food and no longer viable for its intended use. Sources of waste cooking oil are domestic, industrial and commercial products [103]. Waste cooking oils are problematic waste streams that need to manage properly because if WCO is disposed improperly, down streams of the kitchen, the oil solidifies and cause blockages of sewer pipes [98, 104]. Degraded waste cooking oil gets into sewage system and causes corrosion to metal and concrete elements [105]. Thus, the waste cooking oil can be used as an effective feedstock for the biodiesel production via Transesterification [99].

In Pakistan, waste cooking oil sources include hotel chains, confectioneries, restaurants and domestic cooking. Pakistan is basically an agricultural country and has diverse ecological conditions, so the people mainly depend upon the agricultural products. Plants and crops that yield edible oils for cooking purposes are cultivated on extensive scale in the country. These oils are used in local shops, hotels, huts and every home of Pakistan [80]. Pakistani people use meat of cows, buffaloes, camels, goats, poultry on large scale and use fats for cooking purposes. These all are the major sources for collection of waste cooking oil.

#### **5.4 Waste animal fats**

Animal fats and vegetable oils are of two types of biological lipid materials that are made up of mainly triacylglycerides (TAGs) and less diacyglycerides DAG and monoacylglycerides (MAGs) [106]. Fats and oil have similar physical properties and chemical structures such as hydrophobicity, water-insolubility and solubility in nonpolar organic solvents. However, the high fatty acids content in fats and their different distributions make it different from oil. Oils are generally liquid at room temperature while fats and greases are solids due to their high content of saturated fatty acids (SFA). Different waste animal fats such as tallow (mutton tallow from sheep and beef tallow from domestic cattle), pork lard (rendered pork fat), chicken fats and grease. Since, many animal meat processing facilities, rendering companies of collecting and processing of animal mortalities, large food service and processing facilities create large amount of waste animal fats (WAFs), that will be a great opportunity to produce biodiesel from these very cheap raw material [107]. The use of these waste animal fats as a feedstock for biodiesel production will eliminate the need of their disposal.
