Suitability of Biofuels Production on Commercial Scale from Various Feedstocks: A Critical Review

Abstract

The growing demand for energy resources and the increase in greenhouse gas (GHG) emissions has given biofuels a lot of attention. Liquid biofuels can be a significant alternative for the transport sector. Generally, biofuels are categorized into four generations based on the feedstock. This review reports the availability, economic feasibility, and potential of biofuel feedstock in global scenario. Feedstock for first-generation biofuel comprises edible resources impacting the food supply. Second generation biofuels are based on different residual materials and nonedible fuel crops. Cost and technological limita-tions for commercialization hinders this option. Microalgae are the feedstock for third generation biofuels providing the highest yield compared to the other two generations. A scale-up to commercial level is not possible as this requires further development. Genetically modified microorganisms are used as a feedstock for fourth generation biofuel production with the highest possible yield. Third and fourth generation biofuels have potential to replace fossil fuels. This review recommends certain suggestions for sustainable biofuel production.

Process Systems Engineering Approach for the Sustainable Design of Cyanobacteria-Based Integrated Biorefineries and Their Heat Exchanger Network

“…Even though this generation is more promising than the first-generation case, it still has disadvantages like the cost of raw materials and their density, the variable composition of lignocellulosic biomass, generation of inhibitors during presaccharification treatment, end-product inhibition, osmotic and oxidative stress 6 and not yet being economically feasible. 7 Biofuels produced from algae biomass are considered third-generation but are not yet commercially produced due to the high production costs, leading to the need to improve production rates and separation processes efficiency. 8 As algae produce other commercial products, like pigments, bioplastics, and pharmaceuticals, among others, research efforts have been made to study the cultivation of algae alongside the production of value-added compounds under an integrated biorefinery approach.…”

“…On the other hand, the second case involves hydrolysis processes to obtain sugars that are then fermented into ethanol. Even though this generation is more promising than the first-generation case, it still has disadvantages like the cost of raw materials and their density, the variable composition of lignocellulosic biomass, generation of inhibitors during presaccharification treatment, end-product inhibition, osmotic and oxidative stress and not yet being economically feasible . Biofuels produced from algae biomass are considered third-generation but are not yet commercially produced due to the high production costs, leading to the need to improve production rates and separation processes efficiency .…”

Application of adaptive laboratory evolution to improve the tolerance of Rhodotorula strain to methanol in crude glycerol and development of an effective method for cell lysis

“…[ 3 ] Now microbial lipids that are obtained from oleaginous microorganisms become ideal feedstock for the third and fourth generation biodiesel production. [ 4 ] To cut the production cost of biodiesel, researchers are working on producing microbial lipids in economical ways. One way is to develop microorganisms with high lipogenesis capability by using multiple technics, such as mutagenesis, metabolic engineering, and synthetic biological methods.…”

Continuous Fatty Acid Decarboxylation using an Immobilized Photodecarboxylase in a Membrane Reactor

“…[1,2] Nevertheless, the molecular structure disparities between traditional biofuels (such as bioethanol and fatty acid methyl esters) and fossil fuels (i. e. alkanes) hinder their compatibility with commonly utilized engines. [3] In recent years, enzymatic generation of alkane biofuel from renewable fatty acids (for example, from microorganisms and non-edible oils) has emerged in the field of bioenergy. [4][5][6] Fatty acid photodecarboxylase (FAP), membrane-associated proteins isolated from algal chloroplasts that can convert fatty acids into C1-shortened alkane biofuels when stimulated by blue light, have emerged as a participant in the development of a new generation of biofuel.…”