ABSTRACT
Department of Biochemistry, Punjab Agricultural University, Ludhiana, Punjab, India-141004; E-mail: sachdeeksha@gmail.com
8.1 Introduction ................................................................................. 208 8.2 Generations of Biofuels ............................................................... 209
8.2.1 First Generation Biofuels ................................................. 209 8.2.2 Second Generation Biofuels ............................................. 209 8.2.3 Third Generation Biofuels ................................................ 209 8.2.4 Fourth Generation Biofuels .............................................. 210
8.3 Sources of Biodiesel or Feedstock ............................................... 210 8.3.1 Biodiesel from Waste Cooking Oil (WCO) ..................... 210
8.4 Chemical Nature of Biodiesel ...................................................... 212 8.5 Synthesis of Biodiesel by Trans-Esterification ............................ 213 8.6 Factors Affecting Rate of Reaction .............................................. 213 8.7 Catalysis of Transesterification .................................................... 214
8.7.1 Base or Acid Catalysis ..................................................... 214 8.7.2 Enzymatic Catalysis ......................................................... 214
8.8 Microbial Synthesis of Biodiesel ................................................. 214 8.9 Blends ............................................................................................ 215
8.10 Benefits of Biodiesel .................................................................. 215 8.11 Other Uses of Biodiesel ............................................................. 216 8.12 Energy Balance Ratio................................................................. 217 8.13 Challenges .................................................................................. 217 8.14 Conclusion ................................................................................. 218 Keywords .............................................................................................. 218 References ............................................................................................. 218
8.1 INTRODUCTION
Bioenergy is an energy source derived from organic matter or biomass. It can be as low-tech as burning wood on an open fire or as high-tech as developing advanced production methods for biofuels. The unifying factor with all bioenergy sources, however, is that the carbon they contain (and emit when used) comes from plants, and those plants obtain their carbon from the atmosphere. Hence, bioenergy is considered to be renewable.
