Isolation and Characterization of a Marine Microalga for Biofuel Production with Astaxanthin as a Co-Product

Abstract

Microalgae have been considered as a promising biomass for biofuel production, but freshwater resource consumption during the scaled-up cultivation are still a challenge. Obtaining robust marine strains capable of producing triacylglycerols and high value-added metabolites are critical for overcoming the limitations of water resources and economical feasibility. In this study, a marine microalga with lipid and astaxanthin accumulation capability was isolated from Bohai Bay, China. The alga was named as Coelastrum sp. HA-1 based on its morphological and molecular identification. The major characteristics of HA-1 and the effects of nitrogen on its lipid and astaxanthin accumulations were investigated. Results indicated that the highest biomass, lipid and astaxanthin yields achieved were 50.9 g m , respectively, after cultivation for 24 days. The fatty acids of HA-1, identified in their majority as oleic acid (56.6%) and palmitic acid (25.9%), are desirable biofuel feedstocks. In addition, this alga can be harvested with simple sedimentation, achieving 98.2% removal efficiency after settling for 24 h. These results suggest that Coelastrum sp. HA-1 has several desirable key features that make it a potential candidate for biofuel production.

Nutrient Deprivation-Associated Changes in Green Microalga Coelastrum sp. TISTR 9501RE Enhanced Potent Antioxidant Carotenoids

“…The results (Figure S1) showed that the growth, albeit being unsurprisingly suppressed, could still reach OD 730 at around 1.0. Compared to other studies [44], this level of cell mass was at an acceptable level. Prior to the induction condition, the algal colonies on the BG11 agar exhibited a dull-shiny texture, olive green color, and circular shape.…”

“…Coelastrum sp. HA-1, an isolated microalga from Bohai Bay, China, was cultivated under nitrogen-limiting conditions and it produced astaxanthin at a level of 6.36 mg/g dried cell weight [44]. The cultivation of Coelastrum cf.…”

“…The induction condition was a drastic reduction of the nutrient contents, which could also be viewed as a practical advantage in a real production process (cost reduction). Notably, in contrast to the aforementioned studies [44,45], this study serves as the first example of this genus, where the carotenoid profile is characterized by both HPLC-PDA (photodiode array detection) and LC-MS. Molecular identification of this microalgal strain, its growth profiles, and the carotenoid identifications and quantifications are discussed herein.…”

Hydroxyl radical-aided thermal pretreatment of algal biomass for enhanced biodegradability

“…The carbohydrate in algal biomass was quantitatively analyzed according to the NREL Laboratory Analytical Procedures [ 28 ] for biomass using a two-step acid method [ 24 ]. Approximately 1 g (dry basis) of the samples was dispensed into 200 mL Erlenmeyer flasks.…”

“…The overall crystallinity of the macroalgae subjected to the new pretreatment was examined through XRD on a Bruker D8 Advance Diffractometer with Cu Kα radiation ( λ = 0.1541 nm) at 30 kV and 30 mA [ 24 ]. The samples were scanned, and the intensity was recorded in the 2 θ range of 10°–80°.…”