Isolation of a novel strain of Cyanobacterium sp. with good adaptation to extreme alkalinity and high polysaccharide yield

• Published in: Journal of oceanology and limnology 2021-05, Vol.39 (3), p.1131-1142
• Main Authors: Chen, Zishuo, Li, Tao, Yang, Bingjie, Jin, Xuejie, Wu, Hualian, Wu, Jiayi, Lu, Yandu, Xiang, Wenzhou
• Format: Article
• Language: English
• Subjects: Adaptation; Algae; Alkalinity; Aquaculture and Fisheries; Aquatic plants; Bicarbonates; Biochemical composition; Biological contamination; Biomass; Carbohydrates; Carbon; Carbon sources; Chlorophyll; Chlorophyll a; Contamination; Cyanobacteria; Cyanobacterium; Dry weight; Earth and Environmental Science; Earth Sciences; Environmental conditions; Exopolysaccharides; Laboratories; Limnology; Moisture absorption; Morphology; Oceanography; Phycocyanin; Phytoplankton; Polysaccharides; Ponds; Saccharides; Salinity; Science; Sodium; Sodium bicarbonate
• ISSN: 2096-5508; 2523-3521
• DOI: 10.1007/s00343-020-0113-7

The use of high alkaline medium is a feasible way to provide carbon source and prevent biological contamination for the outdoor cultivation of alkaliphilic microalgae and cyanobacteria. A novel cyanobacterial strain was isolated from the open pond of a marine green alga ( Picochlorum sp. SCSIO-45015, Sanya, Hainan) and identified as Cyanobacterium sp. SCSIO-45682. The effects of initial sodium bicarbonate (NaHCO 3 ) concentrations on the growth and biochemical composition of Cyanobacterium sp. SCSIO-45682 were investigated. The results demonstrated that Cyanobacterium sp. SCSIO-45682 had good adaptation to 16.8 g/L NaHCO 3 (the same concentration of NaHCO 3 used in Zarrouk medium for Spirulina ). Moreover, the yields of biomass, polysaccharide, chlorophyll a (chl a ), and phycocyanin increased under high NaHCO 3 concentrations. The maximum final biomass concentration of 2.5 g/L was observed at 8.4 g/L NaHCO 3 , while the highest intracellular total saccharide content of 49.2% of dry weight (DW) and exopolysaccharide (EPS) concentration of 93 mg/L were achieved at the NaHCO 3 concentration of 16.8 g/L. The crude protein content declined under high NaHCO 3 concentrations, which provide a possible explanation for the accumulation of polysaccharide. This study shows a good potential of alkaliphilic Cyanobacterium sp. SCSIO-45682 as a polysaccharide feedstock.