Microbial Bioresources for Biofuels Production: Fundamentals and Applications

Biofuel production is increasingly aroused by new market demands, increased societal pressure on sustainability, and increasingly restrictive action by environmental agencies and legislations. Within the already known and consolidated technologies to produce biofuels from plant biomass (first-generation), there is growing interest in the use of microbial biomass, whose use through different techniques gives rise to second, third, and fourth-generation biofuels. The development of biofuel production technologies from microbial resources play an important economic and environmental role, specifically regarding the bioeconomy and the concepts of biorefinery and circular economy, due to its easy integration into existing industrial systems. Considering the use of different microorganisms (bacteria, yeast, fungi, and microalgae) and classes of molecules produced by them for production of liquid and gaseous biofuels, it is presented the fundamentals of biological, chemical, and thermochemical conversion of microbial-derived molecules such as carbohydrates, lipids, proteins, and/or microbial biomasses to ethanol (2nd, 3rd, and 4th generation), biodiesel, bio-oil, biogas, and biohydrogen.