2.1 Microalgae. The term microalgae refer to the microscopic algae and the oxygenic photosynthetic bacteria, i.e. the cyanobacteria, formerly known as Cyanophyceae (Richmond 2004). The word algae represent a large group of different organisms from different phylogenetic groups, representing many taxonomic divisions. In general algae can be referred to as plant-like organisms that are usually photosynthetic and aquatic, but do not have true roots, stems, leaves, vascular tissue and have simple reproductive structures.(Christi,Y.2007). They are distributed worldwide in the sea, in freshwater and in wastewater. There are many kinds or types of microalgae:
• Green algae. With 7500 species they form one of the largest groups of …show more content…
In general, lower oil strains grow faster than high oil strains (Vasudevan and Briggs, 2008). Microalgae containing 30% oil grow 30 times faster than those containing 80% oil (Becker, 1994). Another challenge is that microalgae usually accumulate oil under stress conditions with slow growth rate. Hu et al. (2008) reported that neutral lipids content, mainly in the form of triacylglycerol (ATG), double or triple increased when the cells were subjected to unfavorable culture conditions. The nitrogen limitation also could increase the oil content in Neochloris oleoabundans (Li et al., 2008) and five Chlorella strains including Chlorella vulgaris, Chlorella emersonii, Chlorella protothecoides, Chlorella sorokiniana and Chlorella minutissima (Illman et al., 2000). So, the ability of microalgae to thrive in extreme conditions should be taken into account for seeking efficient strains to biodiesel …show more content…
In the case of microalgae, the carbon source can be CO₂ and the energy comes from sunlight. As microalgae grow in aqueous suspensions, the manipulation and control of culture condition makes their cultivation feasible, thus productivity is limited mostly by the available of light. Responses by algal cells to nutrients and cultivation environments can be used to manipulate the processes to favour the production of algal biomass. (Benemann, 2002).
The conversion of light energy into chemical energy involves a two-step process known as the dark reaction and light reactions. Dark reaction is the process of carbon fixation reaction that can occur in the presence or absence of light, while light reactions needs illumination for the reaction to occur. The conversion of energy occurs the following reaction (Ho et al,
• Green algae. With 7500 species they form one of the largest groups of …show more content…
In general, lower oil strains grow faster than high oil strains (Vasudevan and Briggs, 2008). Microalgae containing 30% oil grow 30 times faster than those containing 80% oil (Becker, 1994). Another challenge is that microalgae usually accumulate oil under stress conditions with slow growth rate. Hu et al. (2008) reported that neutral lipids content, mainly in the form of triacylglycerol (ATG), double or triple increased when the cells were subjected to unfavorable culture conditions. The nitrogen limitation also could increase the oil content in Neochloris oleoabundans (Li et al., 2008) and five Chlorella strains including Chlorella vulgaris, Chlorella emersonii, Chlorella protothecoides, Chlorella sorokiniana and Chlorella minutissima (Illman et al., 2000). So, the ability of microalgae to thrive in extreme conditions should be taken into account for seeking efficient strains to biodiesel …show more content…
In the case of microalgae, the carbon source can be CO₂ and the energy comes from sunlight. As microalgae grow in aqueous suspensions, the manipulation and control of culture condition makes their cultivation feasible, thus productivity is limited mostly by the available of light. Responses by algal cells to nutrients and cultivation environments can be used to manipulate the processes to favour the production of algal biomass. (Benemann, 2002).
The conversion of light energy into chemical energy involves a two-step process known as the dark reaction and light reactions. Dark reaction is the process of carbon fixation reaction that can occur in the presence or absence of light, while light reactions needs illumination for the reaction to occur. The conversion of energy occurs the following reaction (Ho et al,