Isolation, Identification and Biotechnological Applications of a Novel, Robust, Free-living Chlorococcum (Oophila) amblystomatis Strain Isolated from a Local Pond

Abstract

Bioprospection of novel autochthonous strains is key to the successful industrial-scale production of microalgal biomass. A novel Chlorococcum strain was recently isolated from a pond inside the industrial production facility of Allmicroalgae (Leiria, Portugal). Phylogenetic analysis based on 18S ribosomal ribonucleic acid (rRNA) gene sequences suggests that this isolate is a novel, free-living Oophila amblystomatis strain. However, as our phylogenetic data strongly suggests that the aforementioned taxon belongs to the genus Chlorococcum, it is here proposed to rename this species as Chlorococcum amblystomatis. In order to characterize the biotechnological potential of this novel isolate, growth performance and biochemical composition were evaluated from the pilot (2.5-m3) to industrial (10-m3) scale. The highest maximum areal productivity (36.56 g·m−2·day−1) was reached in a 10-m3 tubular photobioreactor (PBR), as compared to that obtained in a 2.5-m3 PBR (26.75 g·m−2·day−1). Chlorococcum amblystomatis displayed high protein content (48%–56% dry weight (DW)) and moderate levels of total lipids (18%–31% DW), carbohydrates (6%–18% DW) and ashes (9%–16% DW). Furthermore, the lipid profile was dominated by polyunsaturated fatty acids (PUFAs). The highest pigment contents were obtained in the 2.5-m3 PBR, where total chlorophylls accounted for 40.24 mg·g−1 DW, followed by lutein with 5.37 mg·g−1 DW. Overall, this free-living Chlorococcum amblystomatis strain shows great potential for nutritional applications, coupling a promising growth performance with a high protein content as well as relevant amounts of PUFAs, chlorophyll, and carotenoids.

Diversity and substrate-specificity of green algae and other micro-eukaryotes colonizing amphibian clutches in Germany, revealed by DNA metabarcoding

“…An exploratory analysis of all sequences of the 18S rRNA gene from previous studies targeting Oophila (Correia et al 2020;Kim et al 2014;Muto et al 2017;Nema et al 2019) confirmed that strains assigned to Oophila in these studies belong to two distinct clades within Chlorophyta (Dataset 1; Online Resource 4, Fig. S9).…”

“…Therefore, it is likely that "Clade B" algae are more difficult to culture than (many) "Clade A" algae, and the latter are, therefore, more successfully isolated and cultured (or have a high likelihood to contaminate other isolates, even if present in only very minor proportion in a sample). Two other recent studies are in agreement with this hypothesis: firstly, the DNA metabarcoding study of Jurga et al (2020) only found "Clade B" sequences in numerous North American salamander clutches studied; and secondly, Correia et al (2020) obtained a free-living "Clade A" isolate from a pond in Portugal, which they specifically characterize as robust and with promising growth performance even at industrial scale.…”

Polar lipidomic profile shows Chlorococcum amblystomatis as a promising source of value-added lipids

“…Milli-Q water (Synergy, Millipore Corporation, Billerica, MA, USA) was used. Phospholipid internal standards 1,2-dimyristoyl- sn -glycero-3-phosphocholine (dMPC), 1,2-dimyristoyl- sn -glycero-3-phosphoethanolamine (dMPE), 1,2-dimyristoyl- sn -glycero-3-phospho-(10-rac-glycerol) (dMPG), 1,2-dimyristoyl- sn -glycero-3-phospho- l -serine (dMPS), 1,2-dipalmitoyl- sn -glycero-3-phosphatidylinositol (dPPI), N-palmitoyl-D- erythro -sphingosylphosphorylcholine (SM), 1-nonadecanoyl-2-hydroxy- sn -glycero-3-phosphocholine (LPC) were purchased from Avanti Polar Lipids, Inc. (Alabaster, AL), according to the methodology previously described 34 , 35 . DPPH • was purchased from Aldrich (Milwaukee, WI).…”

“…The polar lipidome was determined according to the methodology previously described 34 , 35 . The dried samples were dissolved in CH 2 Cl 2 to a final concentration of 1 ug uL -1 .…”

“…Chlorococcum sp. has been described as a useful tool in carbon sequestration, lipid flocculation in wastewater 30 and carotenoid production 31 , a good source for the production of biodiesel 32 and useful for the food industry 33 , 34 . The production of lutein from Chlorococcum citriforme has already been patented 35 .…”