Ranganathan Rajkumar and Zahira Yaakob

Department of Chemical and Process Engineering University of Kebangsaan, Bangi, Malaysia

CONTENTS

2.1 Taxonomy……………………………………………………………………………………………………. 7

2.1.1 General Characteristics…………………………………………………………………….. 7

2.2 Morphological Identification………………………………………………………………………… 8

2.3 Molecular Identification……………………………………………………………………………….. 9

2.4 Habitats………………………………………………………………………………………………………. 12

2.4.1 Freshwater………………………………………………………………………………………. 12

2.4.2 Marine…………………………………………………………………………………………… 13

References…………………………………………………………………………………………………………… 14

2.1 TAXONOMY

Algae are a diverse group of organisms that can perform photosynthesis efficiently. On the basis of morphology and size, algae can be subdivided and are classified into two main categories: macroalgae and microalgae. Macroalgae consist of mul­tiple cells that organize into structures resembling the roots, stems, and leaves of higher plants (e. g., kelp). Microalgae are an extremely diverse group of primary producers present in almost all ecosystems on Earth, ranging from marine, fresh­water, desert sands, and hot springs, to snow and ice (Guschina and Harwood, 2006). They are colonial or single-celled organisms that have garnered increasing amounts of attention and interest for industrial purposes. They are categorized into divisions based on various characteristics such as morphological features, pig­mentation, the chemical nature of photosynthetic storage products, and the orga­nization of photosynthetic membranes. The four most important algal groups in terms of abundance are green algae (Chlorophyceae), diatoms (Bacillariophyceae), blue-green algae (Cyanophyceae), and golden algae (Chrysophyceae) (Khan et al., 2009). According to estimations reported by Cardozo et al. (2007), they include between 200,000 and 800,000 species, of which about only 35,000 species have been described.