Chapter 4 - Energy plants (crops): potential natural and future designer plants

Abstract

Plants (both lower plants belonging to cyanobacteria and algae and higher plants belonging to angiosperms and gymnosperms) supplement various industries such as agroforestry, food, and municipal waste and can themselves be served as feedstock for various types of renewable biofuels, as well as function as an inexpensive manufacturing platform to provide a multiplicity of items. Although all plants may operate as a potential staple for producing energy and chemicals, some essential characteristics such as short life cycle, higher growth rate, ability to grow under various stress conditions, and above all, no competition exhibited with food crops for space are especially expected from plants designated as energy plants (crops). Also, plants with higher oil (oleaginous) and hydrocarbon (petroplants) contents are considered energy plants. Certain food crops that are grown for use in biofuel production (e.g., sugarcane in Brazil and corn in the United States) or certain other crops that produce large volumes of residues (e.g., wheat and rice straw, sugarcane bagasse, maize stover and cobs, and sorghum stalks) are considered as food as well as energy crops (plants). Although these natural energy plants are important feedstock for various types of biofuels, they have certain inherent constraints that have so far thwarted their large-scale application and the consequent commercialization of biofuel technology. Some important constraints are the recalcitrance of lignocellulosic biomass and the low contents of oil and hydrocarbons in oleaginous and petroplants, respectively. These have prompted the application of genetic approaches to remove these constraints and tailor these plants (designer plants) in such a way that facilitates the rapid commercialization of plant-based biorefinery technologies.