World Journal of Environmental Biosciences
World Journal of Environmental Biosciences
2023 Volume 12 Issue 3

Extraction of Alcohols From Non-Edible Agricultural Weed, Lignocellulouic Feedstock - Alternanthera caracasana


Shree Raksha Yadav Malthesh1, Raghu Ram Achar2, Archer Ann Cathrine3, Kalya Tulasidas Vadiraj1*


1Department of Environmental Science, JSS Academy of Higher Education & Research, Mysore 570015 –India.

2Department of Biochemistry, JSS Academy of Higher Education & Research, Mysore 570015 –India.

3Department of Microbiology, JSS Academy of Higher Education & Research, Mysore 570015 –India.


Since natural resources for fossil fuels are getting harder to find, bioethanol has become one of the most promising and attractive liquid fuels. Bioethanol, which can be made from lignocellulosic materials, is getting more and more attention because it is easy to get, cheap, environmentally friendly, and beneficial. Bioethanol is the perfect fuel substitute in our view. Bioethanol is a cleaner-burning fuel with the potential to match gasoline's performance in internal combustion engines. Accordingly, a study was performed on Alternanthera caracasana as a possible source of bioethanol because of its availability and abundance in nature. It is commonly called Khaki weed and in very few cases this is used as a feedstock in animal husbandry and poultry. A. caracasana can be easily used to extract lignocellulosic material because of its abundance and non-usability. This lignocellulosic material can be subjected to fermentation for the production of bioethanol. The extracted bioethanol was characterized with FTIR and GC-MS for purity and percentage.

Keywords: Biofuel, Bioethanol, Fermentation, Alternanthera  caracasana



Environmentally sustainable energy sources are desperately needed because of the quickly expanding industrialization. The majority of the world's wealth is derived from nonrenewable fossil resources including natural gas, coal, and oil. They are employed in the production of fuel, power, and other things (Sarkar et al., 2012). With an increase in population, modes of transportation, and technological development, fossil fuel use rises, resulting in a depletion of natural raw materials. This circumstance causes to hike. In addition, greenhouse gases, which change the climate and worsen air pollution, are produced by fossil fuels. We now need to look for alternative energy sources due to factors such as the daily increase in global energy consumption, global warming, the depletion of fossil fuel resources, and the rising expense of fuels derived from petroleum. These sources need to be affordable, productive, and efficient while emitting fewer pollutants or having no adverse impacts (Nigam & Singh, 2011; Lhawang et al., 2021; Sirigeri et al., 2022). As a biofuel, plant biomass can be regarded as a good alternative fuel source. Due to its advantages of being easily available, affordable, and advantageous for the environment, bioethanol, which may be produced from lignocellulosic biomass, is growing in popularity (Chiaramonti, 2007).

Bioethanol can be used as a clean fuel in cars in the following forms: E85 (85 percent ethanol and 15 percent gasoline), E100 (100 percent ethanol with or without a fuel additive), and oxy-diesel (usually an 80/10 mixture of diesel, ethanol, and additives and blending agents). Additionally, if it is continuously generated in large quantities, ethanol can be utilized to generate energy. In contrast to the United States, where corn is mostly used to make ethanol, sugarcane molasses is used as the main raw material in India (Krishnan et al., 2020).

One can categorize biofuels as first- or second-generation (Agarwal, 2007). Second-generation biofuels are often produced from lignocellulosic biomass, which includes grasses, wood, and stems.

Under research are numerous second-generation biofuels, including biohydrogen, bioethanol, and mixed alcohols (Agarwal, 2007). "First-generation" bioethanol is produced through the fermentation of raw sugars, whereas "second-generation" bioethanol is produced through the use of raw lignocellulosic materials. Preliminary research is being done on the "third generation" of algae-based bioethanol (Rajeswari et al., 2022). In addition, cellulose plant material represents an untapped supply of fermentable sugars for a major application, particularly as non-food agricultural by-products like rice and wheat straw, bagasse, rice husk, etc.

Lignocellulosic Biomass (LB) like wood (soft and hardwood), agricultural by-products (Corn, wheat, and rice straw), grass, and waste, are captivating and durable alternatives. It is also utilized to produce bio-alcohol because it is available in large quantities. In addition, it is less expensive compared to food ingredients (based on sugar and starch). 442 billion liters of bio-alcohol can be produced annually using LB. The production of biofuels from lignocellulosic raw materials has the potential to replace approximately 30% of conventional fuels currently consumed by the United States (Hashim et al., 2022).

 Furthermore, second-generation ethanol is created from lignocellulosic feedstock, In this study, the main goal is to identify the non-edible plant for the synthesis of bioethanol and the objective was the extraction of bioethanol through a fermentation process (Devi et al., 2022). The study examined the plant A.caracasana as well as extracted bioethanol by fermentation using S. cerevisiae.

A.caracasana is a lignocellulosic plant with a high growth rate such plants can generate bioethanol that can be used as fuel for vehicles. The characteristic feature of this plant is rapid growth is essential to fulfilling the demand for daily usage of fuel. Lignin degradation is a crucial process in the extraction of bioethanol. Since A.caracasana is not a source of food for the human population, the extraction of bioethanol from it will not interrupt the production of food. Furthermore, the use of ethanol as an automobile fuel will benefit the environment by cutting emissions.

It is possible to reduce food consumption by producing bioethanol from lignocellulosic biomass such as A.caracasana, which is abundant. A.caracasana sugar concentration enables it to create ethanol. Having a high sugar content in plants means that bioethanol production has a lot of capability. Different pretreatment methods can be utilized in the conversion of sugar to ethanol, such as hydrolysis. A larger sugar extraction can be achieved using these pretreatment procedures, which break down hemicellulose and lignin. physical pretreatment is a typical pretreatment method that is both simple and effective at breaking down lignin. Fermentation follows the pretreatment of the pretreated material. During the fermentation process, sugar is transformed into ethanol (Krishnan et al., 2020).


Bioethanol fuel contributes significantly to environmental protection since it slows global warming and conserves fossil fuels. It is an alcohol produced from carbohydrates by fermentation. Producing bioethanol from biomass or waste is one method for reducing both crude oil use and environmental pollution. Additionally, lignocellulosic biomasses, such as maize, sugar, molasses, etc., derived from edible sources like trees and grasses are used to produce ethanol feedstocks. Both bioethanol and ethanol have the same physical and chemical properties, but they are made from different materials. In its pure state, bioethanol is indeed a clear, odorless, colorless liquid. It freezes at 112°C and boils at 78°C (Lau et al., 2009) (Figure 1).



Figure 1. Production of bioethanol fuel schematic representation (Haq et al., 2016)




Alternanthera Caracasana commonly known as the khaki weed was chosen as a raw material in this work because it is the most widely grown weed in southern states. Since this weed directly does not compete with the food market, it makes A.caracasana a good choice for bioethanol production. A.caracasana consists of cellulose, hemicellulose, lignin, organic compounds, and some trace compounds; it is a flowering plant species of the family Amaranthaceae it is called a tough weed in some places. A.caracasana weed – Samples were collected in and around the JSS AHER campus in December 2021 (Figure 2).