Characterization of a newly isolated cyanobacterium Trichocoleus desertorum BERC08 as a potential feedstock for the algal biorefinery

Cyanobacteria have numerous biotechnological applications in the environment, industry, pharmaceutics, food, feed, and energy which is why future cascading biorefineries are believed to employ cyanobacteria as their feedstock. The present study evaluated the potential of a newly isolated cyanobacterium for its applications in the multiproduct biorefinery. Based on morphology and the gene sequence of 23S rRNA, the strain was identified as Trichocoleus desertorum. Various abiotic growth factors including light, pH, and nutrients were optimized to achieve enhanced biomass production using various wastewaters as low-cost growth media. Accordingly, a 2.24-fold to 6.97-fold higher biomass production (gL(-1)) and biomass productivity of 0.86 gL(-1)d(-1) with a CO2 fixation rate of 1.576 gL(-1)d(-1) was achieved when cultured in synthetic wastewater. Besides, the impact of wastewater cultivation was studied on the biosynthesis of valuable metabolites including proteins, carbohydrates, lipids, and pigments. Accordingly, the lipid content of the wastewater-cultivated strain was increased from 24 to 30%, and protein content was increased from 27 to 46%. The lipids were trans-esterified to biodiesel which was turned out to be good quality biodiesel, as revealed through GC-MS analysis. Additionally, the wastewater-cultivated strain produced 117.35 mgg(-1) (11.73 % of the total dried biomass) of phycobilin in response to nutrient manipulation, where phycocyanin was shown to be the most prominent pigment with a yield of 94.7 mgg(-1), which covered 80% of the total pigments. These remarkable features reflected the promising potential of this strain to be employed as a feedstock in the multiproduct biorefinery.

Automated summary

This study evaluated the potential of a newly isolated cyanobacterium for its applications in multiproduct biorefinery. By optimizing growth conditions and using wastewater as a low-cost growth medium, the strain showed enhanced biomass production, increased protein and lipid content, and efficient biosynthesis of valuable pigments.