Bioenergy Crops: Recent Advances and Future Outlook

Abstract

Fossil fuels have solved our energy problems since the beginning of the industrial revolution that started in the eighteenth century. However, from past few decades, the world has seen an unprecedented and uncontrolled use of fossil fuels. In the current era, we heavily rely on fossil fuels for energy demands. It is undeniably true that fossil fuels hold the credit of shaping our world, but on the cost of environmental and related hazards. The negative environmental impacts of fossil usage are now being realized, and the search for alternative energy sources has begun. Bioenergy crops are one such energy source that could positively impact the environment to reduce the level of carbon dioxide, emission of greenhouse gases and soil erosion. The biofuel generation using fast growing and photosynthetically efficient bioenergy crops is emerging as a reliable alternative to fossil fuels. Bioenergy plants increase soil carbon and fix atmospheric carbon. In addition, bioenergy crops (miscanthus, sorghum and poplar) could also be used for the phytoremediation of heavy metal-contaminated soils. The bioenergy crops include specific plants that are grown and maintained at lower costs for biofuel production. The bioenergy crops are classified into five types namely, first-, second- and third-generation bioenergy crops, dedicated energy crops and halophytes. The first-generation bioenergy crops include corn, sorghum, rapeseed and sugarcane, whereas the second-generation bioenergy crops are comprised of switchgrass, miscanthus, alfalfa, reed canary grass, Napier grass and other plants. The third-generation bioenergy crops contain boreal plants, crassulacean acid metabolism (CAM) plants, eucalyptus and microalgae. Bioenergy halophytes are comprised of the genera Acacia, Eucalyptus, Casuarina, Melaleuca, Prosopis, Rhizophora and Tamarix. The dedicated energy crops include perennial herbaceous and woody plant species as giant miscanthus, switchgrass, jatropha and algae.