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Rajak, et al.

interest. These challenges highlight the urgent need for and catalysts, such as acidic, alkaline, or biochemical
sustainable alternative energy sources, such as biofuels catalysts, as shown in Figure 1. Methanol is commonly
and biodiesel. At present, fossil fuels account for 80% used due to its affordability, short chain structure,
1,2
of the world’s primary energy consumption, with 58% rapid rate of reaction, and ease of combining with the
of that energy utilized exclusively for transportation. 3,4 resulting media. The catalyst assists in neutralizing
17
There are several advantages to producing biodiesel the molecules of glycerol and fatty acid methyl esters
through lipase catalysis, including easier product (FAME) throughout the transesterification procedure,
separation, reduced effluent generation, and fewer which occurs at temperatures between 60°C and 80°C.
adverse reactions. Free fatty acids (FFAs) and fatty The resulting products are subsequently isolated for
5,6
acid alkyl esters may be processed more easily using purification. Acidic substances, bases, biological
immobilized lipase under moderate reaction conditions, catalysts, or catalysts made from biomass and bio-
unlike traditional homogeneous alkaline catalysis, waste can all accelerate the transformation of fatty acids
which is ineffective at high FFA concentrations. 7,8 during this procedure. 18,19
However, lipases can have several drawbacks, such The manufacturing of biodiesel on a commercial
as slower reaction rates and the potential for enzyme basis frequently uses homogeneous base catalysts,
inactivation caused by high methanol content. 9 such as phosphoric acid, potassium hydroxide (KOH),
The widespread availability of fossil fuels highlights and sodium hydroxide (NaOH). These catalysts offer
the urgent need for alternative, green energy sources. several benefits, including high catalytic activity, quick
20
Natural gas, syngas, hydrogen, and biofuels are notable, response rates, easy availability, low cost, and mild
environmentally benign, and sustainable substitutes. working conditions. Nevertheless, they are extremely
The United States (US), Brazil, the European Union vulnerable to water and FFAs. The reaction may
(EU), and several Asian countries are major participants therefore result in soap and copious volumes of effluent,
in the global biofuel industry. 10,11 Renewable energy raising the cost of manufacturing and operation. In
21
sources and biodiesel contribute to economic growth addition, these considerations reduce the environmental
by generating employment, income, tax revenue, and sustainability of homogeneous base catalysts. 22
expenditures on facilities and infrastructure. Using For processing high FFA raw materials, including
12
alternative fuels, particularly in the transportation animal fats, leftover cooking oil, and most basic
industry, can lessen reliance on crude oil supplies while vegetable oils, homogeneous acid catalysts, such
enhancing the country’s agricultural potential. as sulfuric acid (H SO ), hydrochloric acid, and
2
4
The advantages of alternative fuels outweigh phosphoric acid are more efficient than homogeneous
the disadvantages of fossil fuels. These advantages base catalysts. These catalysts have several advantages,
include non-toxicity, biodegradability, high energy including the capacity to catalyze parallel procedures
efficiency, and reductions in carbon dioxide, sulfur, for transesterification and esterification without
fine particulates, and nitrogen oxide emissions. 13-15 producing soap by-products, along with resistance to
The energy required to produce biodiesel, for instance, water and FFA sensitivity. 23,24 However, a key obstacle
is thought to be between 40% and 90% less than the to commercialization is their slower reaction rate (about
fossil fuels. Additional biochemical advantages include 4,000 times slower) than base catalysts. In addition,
1
high lubricity, low viscosity, a high cetane number, a their extremely acidic and corrosive nature complicates
high flash point, and reduced sulfur dioxide and carbon handling and may compromise the lifespan of the
monoxide emissions. equipment.
Biodiesel is produced by transesterifying triglycerides Biodiesel and biofuel production is usually expensive,
from processed edible or non-edible oils using alcohols, with raw material and processing costs significantly
such as methanol, ethanol, butanol, or amyl alcohol determining the price. Consequently, it is crucial to
25
16

Figure 1. General method for preparing biodiesel

Volume 22 Issue 5 (2025) 2 doi: 10.36922/AJWEP025130095