Characterization of a newly isolated green microalga Scenedesmus sp. as a potential source of biodiesel

Abstract

An oil-producing microalga SP-01 belonging to the genus Scenedesmus was shown to be able to grow on a media containing 5 to 30 g L -1 NaCl. Under mixotrophic condition, the maximum cell dry weight of 3.1 g L -1 and specific growth rate of 0.034 h -1 were obtained at 0.5 g L -1 NaNO 3 and 6 g L -1 acetate. The effects of salinity on the biomass, lipid, and carotenoid productions of the alga SP-01 in mixotrophic mode were investigated. The biomass productivity increased with increasing NaNO 3 concentrations, and addition of NaCl resulted in a higher biomass while NaNO 3 was present. The maximum lipid content was obtained while no NaNO 3 and NaCl was added, and the lipid content decreased with increasing NaNO 3 concentrations or addition of NaCl. The maximum lipid productivities of 67.44 to 68.44 mg L -1 day -1 were obtained while NaNO 3 and NaCl were not added or while 20 g L -1 NaCl and 0.13 g L -1 NaNO 3 were added. The algal lipid was mainly composed of C16 and C18 fatty acids accounting for more than 90% of total fatty acids. Furthermore, lutein and astaxanthin were the main carotenoids.

Nitrogen Deficiency-Dependent Abiotic Stress Enhances Carotenoid Production in Indigenous Green Microalga Scenedesmus rubescens KNUA042, for Use as a Potential Resource of High Value Products

“…In addition, in comparison to the combined effects of N limitation (130 mg L −1 NaNO 3 ), high salinity (343 mM NaCl), and high light intensity (200 µmol m −2 s −1 ) on Scenedesmus sp. in a similar study, lipid productivity and lipid content of S. rubescens KNUA042 cells in the present study were higher [47]. Similarly, in H. pluvialis, combinations of three stress factors (high light intensity + salinity, high light intensity + iron, or salinity + iron) also produced a sustained increase in by-products.…”

“…These results are similar to the maximum yield of 41% obtained for Scenedesmus sp. SP-1 grown in culture media supplemented with 130 mg L −1 NaNO 3 [47]. The lipid content in the S. rubescens KNUA042 cells in our study was higher than the moderate lipid content of 10%-39% obtained from other Scenedesmus species [48].…”

“…Cultivation of the algal strain S. rubescens KNUA042 under a combination of high salinity and N deficiency conditions could further enhance the production of carotenoids such as astaxanthin, canthaxanthin, and lutein relative to TSC cultivation under single stress (only N deficiency) (Figure 6). In Scenedesmus sp., the combination of N-deficiency-dependent light intensity and high salinity seems to increase the production of astaxanthin and canthaxanthin [47]. Coupling several environmental stresses in a single culture condition could become a novel strategy for improving high-value metabolite production; however, the dependency of metabolic pathways on stress type in various algal strains is a complicated development and one that is not yet well-understood [72].…”

A Review of Algae-Based Produced Water Treatment for Biomass and Biofuel Production

“…Other research has corroborated that Scenedesmus sp. can grow optimally at salinities between 0 and 10,000 mg L −1 , with growth possible but inhibited between 10,000 and 30,000 mg L −1 [52]. These research findings indicate that some freshwater algae such as the C. reinhardtii, S. rotundus, and Scenedesmus sp.…”

“…Furthermore, the species level classification of algal sequences under the classification Plantae from the slime sample, indicated that 70% of plastid sequences belonged to the species S. rotundus. This alga is known to be found in a wide range of sub-tropical and desert locations, which indicates the climate (i.e., elongated periods of desiccation and tropical rainfall) experienced by this microalgal species at the PW treatment plant [52][53][54][55][56]. The salinity of the PW treatment plant at the time of sampling was between 5021 and 7294 mg L −1 , which typically is in the range of moderately saline water.…”