Biotechnology is a major interdisciplinary science, combining biology, chemistry, and engineering and incorporating and integrating knowledge from the areas of microbiology, genetics, chemistry, biochemistry, and biochemical engineering. The key word in this context

is biotransformation.

The application of biotechnology to marine organisms and processes is an area of signif­icant industrial importance with ramifications in many areas, including human health, the environment, energy, food, chemicals, materials, and bioindicators. Some areas of interest re­lated to marine biotechnology include the understanding of genetic, nutritional, and environ­mental factors that control the production of primary and secondary metabolites, based on new or optimized products. Furthermore, there has been an emphasis on the identification of bioactive compounds and their mechanisms of action for application in the medical and chemical industry; there are also bioremediation strategies for application in damaged areas and the development of bioprocesses for sustainable industrial technologies (Zaborsky, 1999).

The cultivation of microalgae as part of biotechnology has received researcher attention. The growth conditions and the bioreactors for cultivation have been thoroughly studied (Borowitzka, 1999). The principle behind cultivation of microalgae for the production of bio­mass is the use of photosynthesis (Vonshak, 1997), which involves using solar energy and converting it into chemical energy.

Microalgae are photosynthetic prokaryotic or eukaryotic microorganisms that grow rapidly and have the ability to live in different environments due to their unicellular or simple multicellular structure. Examples of prokaryotic microalgae are the cyanobacteria; green al­gae and diatoms are examples of eukaryotics (Mata et al., 2010).

Cyanobacteria differentiate into vegetative, akinete, and heterocyst cells. The functions of vegetative, akinete, and heterocyst cells are their ability to carry oxygen in photosynthesis, resistance to climactic conditions, and potential for nitrogen fixation, respectively. Green algae have a defined nucleus, cell wall, chloroplasts containing chlorophyll and other pig­ments, pirenoide, and a dense region containing starch granules, stigma, and scourge.

Microalgae exist in various ecosystems, both aquatic and terrestrial. More than 50,000 species are known and about 30,000 are studied (Mata et al., 2010). The main advantages of microalgae cultivation as a biomass source are (Vonshak, 1997):

• They are biological systems with high capacity to capture sunlight to produce organic

compounds via photosynthesis.

• When subjected to physical and chemical stress, they are induced to produce high concentrations of specific compounds, such as proteins, lipids, carbohydrates, polymers, and pigments.

• They have a simple cellular division cycle without a sexual type stage, enabling them to complete their development cycle in a few hours. This enables more rapid development in production processes compared with other organisms.

• They develop in various environmental conditions of water, temperature, salinity, and light.