CARBOHYDRATE RELEASE BY A SUBTROPICAL STRAIN OF <i>SPONDYLOSIUM PYGMAEUM</i> (ZYGNEMATOPHYCEAE): INFLUENCE OF NITRATE AVAILABILITY AND CULTURE AGING<sup>1</sup>

et al. 2020

Bioresour. Bioprocess.

Arthrospira platensis is a cyanobacterium that is of great biotechnological interest, particularly for the food industry, as it possesses a high content of proteins, pigments, lipids and carbohydrates. Cyanobacteria produce extracellular polymeric substances (EPS), which are co-products of secondary metabolism that present thickening or gelling properties. A 3-level factorial design was used to study the combined effect of different nitrate concentrations and photon flux density (PFD) values to evaluate the biomass and EPS production of A. platensis. The best result in terms of biomass production was obtained under condition 6 (2 g L −1 NaNO 3 and 600 μE m −2 s −1) yielding a concentration of 1.292 g L −1. However, condition 1 (0.25 g L −1 NaNO 3 and 200 μE m −2 s −1) produced the greatest EPS yield (111 mg g −1), followed by condition 9 (2 g L −1 NaNO 3 and 1000 μE m −2 s −1). FTIR analyses of EPS samples indicated the presence of carboxylate and sulfate functional groups, and rheological studies of the EPS at 5 and 10 g L −1 revealed a dilute solution behavior.

Section: Introductionmentioning

confidence: 99%

Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

et al. 2020

Bioresour. Bioprocess.

“…However, the intracellular events that lead to EPS production are still being deciphered. Some authors have proposed two events in diatoms: 1) the combined effect of PFD and nitrate starvation reduce cellular growth and cause an excess of assimilated carbon, which is released as carbohydrates; 2) the electrons accumulated in the photosynthetic electron transport chain induce the production of reactive oxygen species (ROS) that can cause cellular damage, thus EPS are produced to act as a protection barrier against these ROS (Miklestad 1995;Piedras et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

et al. 2020

Preprint

Arthrospira platensis is a cyanobacterium that is of great biotechnological interest, particularly for the food industry, as it possesses a high content of proteins, pigments, lipids and carbohydrates. Cyanobacteria produce extracellular polymeric substances (EPS), which are co-products of secondary metabolism that present thickening or gelling properties. A 3-level factorial design was used to study the combined effect of different nitrate concentrations and photon flux density (PFD) values to evaluate the biomass and EPS production of A. platensis. The best result in terms of biomass production was obtained under condition 6 (2 g.L-1 NaNO3 and 600 μE.m-2.s-1) yielding a concentration of 1.292 g.L-1. However, condition 1 (0.25 g.L-1 NaNO3 and 200 μE.m-2.s-1) produced the greatest EPS yield (111 mg.g-1), followed by condition 9 (2 g.L-1 NaNO3 and 1000 μE.m-2.s-1). FTIR analyses of EPS samples indicated the presence of carboxylate and sulfate functional groups, and rheological studies of the EPS at 5 and 10 g.L-1 revealed a dilute solution behavior.

“…However, the knowledge about the events that explain the process is still scarce. Some authors described two events in diatoms: the combined effect of PFD and nitrate starvation decreased the cellular growth and caused an excess of carbon assimilated, which is released as carbohydrates; the electrons accumulated at photosynthetic electron transport chain could induced the oxygen reactive species (ROS) and cause cellular damagethe EPS production acts as a protection barrier against this ROS (Miklestad 1995;Piedras et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

et al. 2020

Preprint

Arthrospira platensis is a cyanobacterium that exhibits a large biotechnological interest for the food industry because of its high protein content, pigments, lipids and carbohydrates. The extracellular polymeric substances (EPS) are co-products of secondary metabolism that may present thickening or gelling property. A 3-level factorial design was used to study the combined effect of different nitrate concentrations and photon flux density (PFD) to evaluate the biomass and EPS production by Arthrospira platensis. The best result for biomass production was obtained under condition 6 (2 g.L-1 NaNO3 and 600 µE.m-2s-1) leading a biomass concentration of 1.292 mg.L-1. Condition 1 (0.25 g.L-1NaNO3 and 200 µE.m-2s-1) produced the major EPS yield (111 mg.g-1) followed by condition 9 (2 g.L-1NaNO3 and 1000 µE.m-2s-1). The present of carboxylate and sulfate functional groups was identified in EPS samples. Rheological studies performed for some EPS products at 5 and 10 g.L-1 concentrations revealed a dilute solution behavior.