Читать книгу Biomolecular Engineering Solutions for Renewable Specialty Chemicals - Группа авторов - Страница 54

The increase in energy demand globally is affecting environment due to global warming and depletion of nonrenewable energy sources. Conventional fossil fuel sources such as petrol, diesel, natural gas, and coal, which were considered to be the primary sources earlier are getting exhausted due to extensive uses (Kumar et al., 2017). A 37% surge in fuel demand by 2040 has been estimated due to the rapid increase in demand (Joshi et al., 2017). Besides this the petroleum‐based fuel upon burning releases greenhouse gases. This requires a renewable substitute of petroleum‐based fuels. Biofuels are the renewable energy source produced by photosynthetic organisms utilizing Earth’s biggest fuel source, the Sun as the carbon source. Harvesting solar energy via photosynthesis is one of nature’s noteworthy achievements that could also be a solution for the future worldwide economy. Earlier biofuels were produced from plants known as the first generation of biofuels. They are mainly generated from wheat, barley, corn, oilseed, sunflower, etc. the plants, which are rich in carbohydrates and oils. Biofuels produced by them compete with agriculture croplands leading to crisis in food production for human beings (Surriya et al., 2015). Additionally, harvesting of plants take full season and then processing the complex sugars from plants to simpler sugars that can be used by microorganisms limits the production of biofuel (Voloshin et al., 2019). Second generation of biofuels solves the problem of utilizing croplands as they are based on agricultural waste, forest dregs, waste wood residues, and organic waste materials. Biofuels from algae are considered to be third‐generation biofuels. Microalgae and cellulolytic bacteria are fast growing and can fix CO₂ (Dragone et al., 2010). Fourth‐generation biofuels use genetically modified organisms such as algae and cyanobacteria and metabolic engineering to produce biofuels (Dutta et al., 2014). Bioethanol, biodiesel, biogas, biohydrogen, etc. come under biofuel.