Bioprospecting for fast growing and biomass characterization of oleaginous microalgae from South–Eastern Buenos Aires, Argentina

Isolation and Characterization of Native Microalgae from the Peruvian Amazon with Potential for Biodiesel Production

“…In contrast, all cultures displayed a lag phase pattern in their growth profile under −N medium (Figure 2). These findings corroborate the results obtained by other researchers, who demonstrate that the specific growth rate is directly proportional to the initial nitrate concentration [46,59,64,65], because the reduction or cessation of microalgae cell division is due to nitrogen limitation [66], which is a key nutrient for protein and nucleic acids de novo biosynthesis; consequently, causing an arrest in the early part of the microalgae cell cycle [67,68]. In accordance with these reports, Li et al [69] showed that nitrogen deficiency induced, in the green microalgae Micractinium pusillum, a downregulation in the expression of genes involved in cell growth and cell cycle regulation.…”

“…and total carbohydrate content (from 11.9% in Acutodesmus obliquus to 96.3% in Chlorella lewinii), but showed a decreased in total protein levels (from 24.2% in Acutodesmus obliquus to 54.5% in Chlorella lewinii) in comparison to +N cultures (Figure 3). These results are in accordance with well-documented results obtained by other researchers with several microalgae species of the genera Acutodesmus, Ankistrodesmus, Botryococcus, Chlamydomonas, Chlorella, Desmodesmus, Dunaliella, Haematococcus, Neochloris, Phaeodactylum, Pseudokirchneriella and Scenedesmus [46,50,58,59,64,[75][76][77][78][79][80]. Nevertheless, the accumulation of total lipid induced by nitrogen deficiency is not correlated with lipid productivity, but rather is due to a decline and stopping of the microalgae specific growth rate [75].…”

“…strain NAN001). These percentage values in total lipid content are similar to several microalgae species of these genera isolated and characterized by other researchers worldwide [20,45,46,[48][49][50]57]. Furthermore, it is important to emphasize that lipid content is dependent on the different growth phases.…”

“…For example, the ITS2 rDNA region is thought to be an excellent marker for molecular phylogenetics studies in lower taxonomic levels, due to being highly divergent and fast-evolving, which can discriminate among closely-related organisms, which otherwise display almost identical sequences [43,44]. For this reason, the molecular identification based in phylogenetic analysis of ITS2 rDNA gene sequences is commonly used to identify and/or delineate species [20,45,46]. To realize phylogenetic analysis, genomic DNA of each isolate strain was purified and used for PCR amplification of ITS2 rDNA.…”

“…Overall, the identification of native microalgae strains presented a good correspondence between morphological characters and sequence-based phylogenetic analysis. Microalgae species of these genera were also isolated from different countries of the world, such as Brazil [47], Argentina [46], United States [48], India [20], Egypt [49], Taiwan [50], South Korea [45] and China [51]. Some of these microalgae genera, such as Ankistrodesmus, Chlorella, Desmodesmus and Scenedesmus, were used in large-scale biodiesel production using photobioreactors and raceway pond systems [52,53].…”