​Production and Characterization of Biodiesel from Fatty Residues of Capra hircus

India has more than 1,176 slaughterhouses and 75 modern abattoirs; from hundreds of illegal slaughterhouses, slaughterhouses produce a massive amount of solid waste released into the environment. Livestock waste is a significant source of greenhouse gas, pollution, pathogens and odour. 40% of global methane is produced by agriculture and livestock by-products, followed by 18% from waste disposal globally (EPA, 1998). The globe’s meat production from pork, beef and poultry is 42.7%, 23.9% and 33.4%, respectively, including non-edible organs. These non-edible organs are a great energy source because they produce different valuable products such as fat, collagen, keratin etc. The visceral organs of Pila globosa were used to produce biodiesel as an alternative fuel source (Deshpande Sadhana et al., 2015). In recent years, there has been rising interest in biodiesel for its use as a chemical addition or substitute to petroleum-based diesel fuel (Anildo Cunha et al., 2013). Biodiesel is one of the essential sustainable alternate bioenergy source (Karmakar Anindita et al., 2017). In recent years, bioenergy has drawn attention as a sustainable energy source because of growing energy needs, rising oil costs, the pursuit of clean, renewable energy sources and boosting farm income in developed countries (Vignesh et al., 2013). Among the bio-fuels, biodiesel seems to be at the forefront because of its environmental credentials, such as renewability, biodegradability and clean combustion behavior (Tau Dong et al., 2016). Fatty acids are the primary component of lipids and play a crucial role in a biological system. Fatty acids can exist as accessible and bound forms, such as cholesterols and phospholipids (Benjamins et al., 2012). The fatty residues are extracted by using ethanol. The sugarcane industry waste was utilized to produce ethanol (Sing et al., 2012). The vegetable oil is used to produce biodiesel and it analyzes with the help of FT-IR spectroscopic techniques and compared with the standard value (Lawan et al., 2019; Holcapek et al., 1999).

Collection and separation of waste organ sample
 
The 250 gm waste organs, including fatty residues of Capra hircus, were brought locally from a meat shop. The sample is collected from Mulund East and is identified in the Department of Zoology, KET’S V.G. Vaze College (Autonomous), Mumbai. The collected samples (stomach, skin, fat bodies etc.) were washed with fresh water to remove sand and external debris. The cleaned sample was stored in the refrigerator at 4°C and used to extract fat (Anandganesh, 2016). Further experimentation processes were conducted in the Department of Zoology, Vidya Pratishthan’s Arts, Science and Commerce College, Baramati. The present work was carried out during the year 2021-22.
       
Extraction of fat residues
 
Some traditional methods such as the Soxhlet method, Floch, Bligh and Dyer with particular combinations of organic solvents are used for the oil extraction. The Soxhlet apparatus mainly consists of three compartments: a flask, extraction chamber and condenser (Hewavitharana et al., 2020). First, the visceral organs, including fat bodies, were chopped into small pieces using a fine blade. Next, the chopped pieces of the 250 gm sample were placed in a porous thimble for fat extraction. Finally, add the 200 ml of ethyl alcohol to a 500 ml round bottom flask of the soxhlet apparatus (Benjamin et al., 2019). The alcoholic fat sample was collected within 24 hours through the Soxhlet apparatus.
 
Recovery of solvent from sample by rotary evaporators
 
Extracted fat samples separated extracted fat and solvent through a rotary evaporator (Nor et al., 2018). After separation, the solvent is collected in a separate chamber and the mass of the fat sample remains measured and carried for the Purification. The 38 gm of fat sample and 98 ml of ethyl alcohol were reutilized with the help of an evaporator.
 
Analysis of fatty residues by FT-IR spectrophotometer
 
The extracted fat sample was analyzed with the help of Fourier Transform Infrared Spectroscopy (FT-IR) spectroscopic techniques (Rohman et al., 2011). The different graphical peak values were compared with the help of traditional values as described in Table 1.
 

 
Trans-esterification reaction for the production of crude biodiesel
 
A pre-treatment is needed for producing biodiesel from animal fat because it contains a high amount of free fatty acid (FFA) and water, reducing biodiesel yield (Gebremariam et al., 2018). Biodiesel is produced through a trans-esterification reaction. Different catalysts are available for biodiesel production (Fidel et al., 2020). Those most typically used trans-esterification reactions are alkalis (sodium hydroxide, sodium methoxide, potassium hydroxide, potassium methoxide, sodium amide, sodium hydride, potassium amide and potassium hydride), acids (sulfuric acid, phosphoric acid, hydrochloric acid or organic sulfonic acid), heterogeneous catalysts like enzymes (lipases) and complex catalysts like silicates, zirconias, nanocatalysts, etc. (Fidel et al., 2020). Sodium and potassium hydroxides run pretty well and methoxides perform better but are more expensive (Atabani et al., 2012). For trans-esterification of refined sunflower oil treated with ethanol using potassium hydroxide (Kumar et al., 2014). So, we prefer the 0.96% wt. Potassium hydroxides as the catalyst. So, for the trans-esterification reaction, 36 gm. animal fats are treated with 100 ml ethyl alcohol in the presence of potassium hydroxide and produce the two compounds respectively, 32 ml biodiesel and 65 ml glycerol. After the trans-esterification reactions, a prepared sample that is added into the separating funnel and separates the biodiesel and glycerol sample later is stored in the laboratory.
 
Estimation of crude biodiesel
 
After the completion of the trans-esterification reaction, extracted samples were analyzed with the help of the FT-IR spectroscopic technique and determining the different functional groups, wavelength and intensity to confirm crude biodiesel (Holcapek et al., 1999).

Accounts of samples obtained are maintained after different steps of extraction
 
In the present study, the fat content was extracted from the waste organs of Capra hircus in ethyl alcohol solvent through the Soxhlet apparatus method (Benjamin et al., 2019). The 38 gm of fat residues were produced using 250 gm of waste organs of Capra hircus. Then, we purified the extracted sample and got 38 gm of fatty residues and 98 ml of ethyl alcohol recovered with the help of evaporators. The 36 gm of fatty residues after extraction were preceded by biodiesel production through trans-esterification reaction. For the production of biodiesel, use 0.96% wt. KOH as the catalyst and 36 gm of fatty residues and 100 ml ethyl alcohol and got the two compounds respectively 32 ml of crude biodiesel and 65 ml of glycerin. Both of the samples were separated through a separating funnel. The extracted crude biodiesel is analyzed with the help of FT-IR Spectro photometer.
       
The percentage of extracted samples was calculated and represented in Fig 1. The 15.20% fat and 49% ethyl alcohol (Solvent) were removed through the separation process. The 23.18% crude biodiesel and 71.01% glycerin content were obtained through the trans-esterification reaction.
 

 
Characterization of fat sample of Capra hircus
 
Fatty acids are an essential component of lipids in living organisms, including plants, animals and different microorganisms. Therefore, the extracted fatty residues were analyzed with the help of FT-IR spectroscopic method (Fig 2). The fourier transform Infrared Spectroscopy (FT-IR) can mainly represent the information on lipid structure and functional group (Xu et al., 2016).
 

       
The Spectra of the fat content of Capra hircus in Fig 2 recorded the different wavelength peaks. Many functional groups were recorded in FT-IR spectra of fatty residues of Capra hircus. It includes 3552.28 cm^-1, 2974.23 cm^-1, 2927.94 cm^-1, 2895.15 cm^-1, 1647.21 cm^-1, 1381.03 cm^-1, 1350.17 cm^-1, 1327.03 cm^-1, 1274.95 cm^-1, 1085.92 cm^-1 and 879.54 to 439.77 cm^-1 respectively. The wavelength 3552.28 cm^-1 represents the strong peak of the functional group Carboxylic acid OH stretch. The range of peak value 3552.28 to 2974.23 cm^-1 was recognized as -C=CH (Cis double bond stretching) can be correlated with monounsaturated fatty acid (MUFA) (Rohman et al., 2011). The 2974.23- 2927.94 cm^-1 and 2895.15 cm^-1 wavelengths represented the -C-H Stretch and -C-H aldehydic functional groups, respectively (Table 1). The weak peak was recorded in the sample, including 1647.21 cm^-1, 1381.03 cm^-1, 1350.17 cm^-1, 1327.03 cm^-1 and 1274.95 cm^-1 representing the functional groups; for example, C=C alkene, CH₃ bend, C-O-C stretch and NO₂ Stretch (Asmatula et al., 2019).
 
Characterization of crude biodiesel sample
 
The biodiesel sample was analyzed using the FT-IR spectroscopy technique to monitor the trans-esterification reaction. The spectrum of blends of biodiesel is displayed in Fig 3. Many peaks of wavelength were recorded by FT-IR in biodiesel sample including 3408.22 cm^-1, 2954.95 cm^-1, 1742.72 cm^-1, 1463.97-1097.50 cm^-1 and 719.41-449.41 cm^-1. The most strong peak in the spectrum, the C=O ester stretch at 1741.72 cm^-1, is recorded. These peak values represent biodiesel’s presence in the extracted sample (Ault et al., 2012).


       
However, the weak peaks at 3408.22 cm^-1 are representing the Alcohol OH stretch in the given sample. The other different functional groups were recorded from the FT-IR Spectrum of crude biodiesel.

We concluded that the slaughterhouse waste organs could be used to commercialize fat content and crude biodiesel. The Soxhlet apparatus produced fat content in ethyl alcohol as a cheap solvent. The animal fat was used for trans-esterification reaction to produce two actual contents: crude biodiesel and glycerin. Finally, we concluded that Fourier Transform Infrared Spectroscopy (FT-IR) can be used to analyze animal fat at frequency regions from 4000 cm^-1-700 cm-1 and crude biodiesel peak represented the functional group C=O ester stretches at 1742.72 cm^-1 are confirmed. Present research work utilizes the rapid and cheap method to produce animal fat and biodiesel content.

We thank Dr. B.B. Sharma, Advisor,  Kelkar Education Trust, Mumbai,  Principal Prof. (Dr.) Preeta Nilesh, KET’s V.G. Vaze College of Arts, Science and Commerce (Autonomous), Mumbai, Dr. S.S. Barve, Dy. Director, Scientific Research Center, Mumbai and Principal Dr. Bharat Shinde, Vidya Pratishthan’s Arts, Science and Commerce College, Baramati, Pune, for the encouragement and providing facilities.

None.