ABSTRACT
Since the middle of the nineteenth century, fossil fuels have been the main energy source consumed by humanity. In the beginning, coal was rst mined and consumed at an industrial level as a result of the First Industrial Revolution, from 1760 to around 1840, in Great Britain and around Europe. Petroleum or crude oil was also consumed during this period; however, it was not until the Second Industrial Revolution and the advent of the internal combustion engine that oil started to be produced and consumed at industrial levels. As of 2012, the U.S. Energy Information Administration (EIA) projected that the highest consumed energy source, in the United States, was petroleum (36%), followed by natural gas (26%), coal (18%), renewable energy (9%), and nuclear electric power (8%) (EIA, 2013). As fossil fuels are formed from fossilized remains of organisms over long geological periods
CONTENTS
18.1 Introduction ........................................................................................................................ 371 18.2 Microalgae........................................................................................................................... 373
18.2.1 Microalgal Diversity .............................................................................................. 373 18.2.2 Cell Wall .................................................................................................................. 374
18.2.2.1 Chloroplasts ............................................................................................. 375 18.2.2.2 Cellular Division ..................................................................................... 376 18.2.2.3 Growth Modes and Metabolism ........................................................... 377
18.3 Microalgae and Biofuel ..................................................................................................... 378 18.3.1 Biofuel Generalities................................................................................................ 378 18.3.2 Lipid Metabolism ................................................................................................... 379
18.3.2.1 Photosynthetic Efciency ....................................................................... 379 18.3.2.2 TAG Synthesis ..........................................................................................380 18.3.2.3 Lipid Accumulation ................................................................................ 381
18.3.3 Algal Culture and Genetic Manipulation ..........................................................383 18.4 Microalgae and Biohydrogen Production ......................................................................385
