Due to increasing power demand and the utilisation of natural resources in growing countries, the use of biomass and biofuels is emerging. The role of thermophilic ligninolytic bacterial enzymes in the biomass-to-biofuel conversion process is discussed in this chapter. Various elements of biomass feedstocks, compositions, and viabilities of lignocellulosic biomass are illustrated. The lignocellulosic biomass pre-treatment methods, inhibitors during the pre-treatment process, hydrolysis methods, and bacteria production processes have been explained. The processes for isolation, screening, and maintenance of cellulolytic bacteria are exemplified through suitable schematics. The utilization of agro-waste in the ethanal and biofuel production processes is also exemplified.
TopIntroduction
Industries, residences, services, and transportation use more energy overall on a daily basis. India is now the fourth-largest energy consumer in the world, thanks to growing primary energy consumption. Biomass-based fuels have the potential to produce energy that is clean, carbon-neutral, and sustainable. Given its biodegradability, low toxicity, and ability to mix well with gasoline, biofuel is being looked at as a potential replacement for fossil fuels. The world's crude oil reserves are limited, and they are depleting considerably more quickly than in the past. A mesoscale biorefinery sector may be supported by the biofuel industry, which could also hold down the growth of agriculture and forestry and cut greenhouse gas emissions by an estimated 86 percent compared to gasoline.
Biofuels cover a wide range of feedstocks, conversion methods, and applications. About 51,000 million litres of ethanol have been produced worldwide, with the USA and Brazil ranking as the top two producers (Abualigah et al., 2022). The most plentiful bioresources are thought to be wood and agricultural waste, often known as lignocellulosic biomass, which are created by photosynthesis using solar energy and atmospheric CO2. Crystalline celluloses make up 40–50% of lignocellulosic biomass, and obstinate lignin makes up 10–25% of it. It can be used as a powerful raw material for several biofuel generations and is generated on an annual basis in the range of 10-20 tonnes.
A fuel made from biomass is known as a “biofuel” and can be either solid, gaseous, or liquid. Examples of liquid biofuels include biodiesel, plant oils, methanol, and ethanol. It is mostly made up of timber, forestry products, animals, aquatic vegetation, and agricultural products. With 34 billion litres produced, the United States has maintained its position as the world's top producer of ethanol. Brazil's overall bioethanol production increased from 18 billion litres to 27 billion litres. Numerous other nations, like China, Thailand, Germany, France, Spain, and Sweden, are also carrying out sizable national biofuels’ programmes. A key fuel source for long-term use is ethanol. In addition to the necessary herbicides and fertilisers for production, it requires extremely little water. Organic resources, such as plant and animal waste, are used to make biofuels. The most necessary source to obtain the end product as a fuel is living things that can use CO2. Organic resources utilised in their natural state, such as wood chips, fuelwood, and pellets, are considered primary biofuels. Bioethanol, biodiesel, biobutanol, biogas, and biohydrogen are examples of secondary biofuels that are produced by the processing of biomass. They are divided into first, second, third, and fourth generation biofuel categories depending on the production process and type of feedstock used.
Fermentation is used to create bioethanol from source materials that include significant amounts of sugar and starch. The ethical dilemma of “food vs fuel” is linked to biofuels made from food crops.
Lignocellulosic biomass, non-food crops, agricultural waste, and energy crops are used to make second-generation biofuels. Algal biomass biofuels, also referred to as algae fuel, are categorised as third-generation biofuels. Crop leftovers are common feedstocks that are utilised all over the world to produce biofuels. Biofuel is a renewable energy source that reduces the need for fossil fuels. It is created using renewable plant-based energy sources like algae, hydrocarbons, and other alternative types of energy(Khan et al., 2022). When compared to traditional fuels, biofuels like biogas, bioethanol, and biodiesel can offer sources of fuel that are environmentally benign. Crops offset the CO2 emitted by vehicles because plants take up CO2 as they grow. They discuss issues including rural unemployment and energy-related problems.
Their growth and output have an impact on the policies that affect numerous industries involved in the nation's socioeconomic elements. Utilizing biofuels leads to better combustion, which reduces hydrocarbon emissions. New renewable energy sources are being developed by some nations, such as the manufacturing of cellulosic ethanol. Compared to other fuels, bioethanol has attracted increased attention as a clean and renewable fuel. Since fuel crops absorb carbon dioxide, using bioethanol will cut greenhouse gas emissions while also improving air quality. By blending bioethanol with gasoline, we may prevent over-dependence on countries that produce most of the world's oil while also extending the useful life of depleting non-renewable resources.