Exopolysaccharide production in Anabaena sp. PCC 7120 under different CaCl2 regimes

Abstract

Influence of various levels of CaCl (0, 1, 10 and 100 mM) on exopolysaccharide production has been investigated in the cyanobacterium 7120. At the concentration of 1 mM CaCl, growth was found to be stimulatory while 100 mM was sub lethal for the cyanobacterial cells. Estimation of EPS content revealed that EPS production depends on the concentration of calcium ions in the immediate environment with maximum being at10 mM CaCl. A possible involvement of gene in the process of EPS production was also revealed through qRT-PCR. Further, FTIR-spectra marked the presence of aliphatic alkyl-group, primary amine-group, and polysaccharides along with shift in major absorption peaks suggesting that calcium levels in the external environment regulate the composition of EPS produced by 7120. Thus, both quantity and composition of EPS is affected under different calcium chloride concentrations presenting possibilities of EPS with novel unexplored features that may offer biotechnological applications.

Exploring the Valuable Carotenoids for the Large-Scale Production by Marine Microorganisms

“…Several wild-types, as well as genetically-engineered species of Nostoc , have been used to investigate the production of exopolysaccharides, such as polyhydroxyalkanoates [ 123 ], and the production of hydrogen [ 124 ]. Moreover, several species of Anabaena have also been reported to serve as attractive sources for the production of exopolysaccharides [ 125 ] and carotenoids as feedstock for biodiesel [ 126 ]. However, the production of rare carotenoids from Nostoc and Anabaena , as well as the processes for the large-scale production of their biomass have not yet developed completely.…”

Co‐production of bioethanol and commercially important exopolysaccharides from the marine cyanobacterium Synechococcus elongatus BDU 10144 in a novel low‐cost seawater‐fertilizer‐based medium

“…It turns out that EPS is denser and rigid, resulting in aggregates with a small rod‐like shape and even meshwork in some spots. EPS extracted from filamentous species does not exhibit a condensed crisscross pattern which may be due to the fact that the test organism is single‐celled compared to those extracted from filamentous species 83 . Indeed, the structure, composition and viscosity of EPS are influenced by a variety of factors, including the culture medium's composition, carbon and nitrogen sources, mineral salts and strain type 84 …”

“…EPS extracted from filamentous species does not exhibit a condensed crisscross pattern which may be due to the fact that the test organism is single-celled compared to those extracted from filamentous species. 83 Indeed, the structure, composition and viscosity of EPS are influenced by a variety of factors, including the culture medium's composition, carbon and nitrogen sources, mineral salts and strain type. 84 The chemical composition of the EPS is determined by the environmental conditions as well as the microorganism under investigation.…”

Exploiting a perchlorate-tolerant desert cyanobacterium to support bacterial growth for in situ resource utilization on Mars

“…Indeed Anabaena sp. PCC 7120 was reported to grow in 1 mM CaCl 2 (Singh et al ., 2016). Here Chroococcidiopsis cells were grown in concentrations of 0.24 mM CaCl 2 and 0.30 mM MgSO 4 supplied by the BG-11 medium (Rippka et al ., 1979) while 0.5 mM Mg 2+ and 0.75 mM Ca 2+ were present in 2.4 mM perchlorate ions supplied as a 60 and 40% mixture of Mg- and Ca-perchlorate, respectively.…”