Effect of silicate limitation on growth, cell composition, and lipid production of three native diatoms to Southwest Texas desert

To understand the potential of Nitzschia spp. in the biofuels industry, growth characteristics and fatty acid composition of three strains of Nitzschia grown at five silicate concentrations were investigated. The algae were grown in two stages with temperatures and light: dark cycles designed to mimic spring/fall conditions in the southern United States. First, cells were grown on Si concentrations ranging from 0.2 to 10.6 mol m(-3). Second, they were grown for four more days with half of the initial medium replaced by a Si-free medium. Growth rates ranged from 0.16 to 0.30 day(-1) in Si media and 0.07-0.39 day(-1) in Si-free media. The total lipid content in the Si-free media ranged from 26.6 to 255 mg g(-1) AFDW. In all cases, the fatty acid distribution was similar between strains, with palmitic acid (16:0) and palmitoleic acid (16:1) dominant. The results show that lipid production of native Nitzschia is strain-specific, and all three strains are potential candidates for the biofuel industry.