Nutritional optimization of Arthrospira platensis for starch and Total carbohydrates production

Abstract

Present study aims to optimize the production of starch and total carbohydrates from Arthrospira platensis. Growing concerns toward unprecedented environmental issues associated with plastic pollution has created a tremendous impetus to develop new biomaterials for the production of bioplastic. Starch-based biopolymers from algae serve as sustainable feedstock for thermoplastic starch production due to their abundant availability and low cost. A. platensis was cultivated in Zarrouk's medium at 32 ± 1 C and exposed to red light with a photoperiod of 12:12 hr light/dark. Growth kinetics studies showed that the maximum specific growth rate (μ max ) obtained was 0.059 day −1 with the doubling time (t d ) of 11.748 days. Subsequently, Zarrouk's medium with different concentrations of sulfur, phosphorus and nitrogen was prepared to establish the nutrient-limiting conditions to enhance the accumulation of starch and total carbohydrates. In this study, the highest starch accumulated was 6.406 ± 0.622 mg L −1 under optimized phosphorus limitation (0.025 g L −1 ) conditions. Nitrogen limitation (0.250 g L −1 ) results demonstrated significant influenced (p < 0.05) on total carbohydrates (67.573 ± 2.893 mg L −1 ) accumulation in A. platensis. The starch accumulation in A. platensis was significantly affected (p < 0.05) by phosphorus limitation (0.0025 g L −1 ). Subsequently, the optimized phosphorus concentration was coupled with mixotrophic cultivation to further enhance the starch accumulation. The results obtained indicated that, the starch (11.426 ± 0.314 mg L −1 ) and carbohydrates (43.053 ± 2.986 mg L −1 ) concentration obtained was significantly high (p < 0.05) under mixotrophic cultivation. Therefore, it shown that nutrient limitation and mixotrophic cultivation are viable strategies to enhance the accumulation of starch and total carbohydrates in A. platensis. K E Y W O R D SArthrospira platensis, mixotrophic, nutrient limitation, starch and carbohydrates

Application of an in situ CO2–bicarbonate system under nitrogen depletion to improve photosynthetic biomass and starch production and regulate amylose accumulation in a marine green microalga Tetraselmis subcordiformis

“…Considerable microalgal starch accumulation with usually more than 50%DW stored intracellularly occurs under stressful conditions such as nutrient deprivation and high irradiance, with nitrogen depletion (−N) or nitrogen limitation (±N) being the most widely studied strategies for the improvement of starch production [2, 4–7]. In general, the −N cultivation, which in essential applies a low cell density and short cultivation time without extra or with very small amounts of nitrogen supply, can enable a relatively high light availability for an individual microalga that tends to facilitate the rapid starch accumulation with high starch productivity and content; in contrast, ±N cultivation employs a limited nitrogen supply for cell growth, which needs longer cultivation time and can get more biomass and improve starch concentration [5].…”

The Hypoxia-Associated Localization of Chemotaxis Protein CheZ in Azorhizorbium caulinodans

“…Compared to the group with nitrogen source (L3+C+N), the nitrogen limitation (L3+C-N) decreased the ratio of CheZ polar localization from 10 to 5% of cells showed ( Figures 7A , B ). For some bacteria, under nitrogen limiting conditions and excessive carbon source, they could accumulate glycogen, polyhydroxyalkanoates, or other substances to response to harsh environments ( Blaby et al, 2013 ; Mozejko-Ciesielska et al, 2018 ; Lai et al, 2019 ). Interestingly, under nitrogen limitation, CheZ-GFP proteins in many cells are squeezed from both ends and converge in the middle of cells ( Figure 7A ), which is different from common diffuse localization pattern, suggesting A. caulinodans may also produce glycogen-like molecules affecting the distribution of CheZ-GFP.…”

“…No matter under carbon or nitrogen limiting conditions, A. caulinodans ORS571 cells cannot grow ( Liu et al, 2019 ), but showed opposite localization patterns of CheZ (polar or diffuse). Under nitrogen limitation and excess carbon source conditions, cells can form glycogen, polyhydroxyalkanoates, or other substances to response to harsh environments ( Blaby et al, 2013 ; Mozejko-Ciesielska et al, 2018 ; Lai et al, 2019 ). Under the condition with carbon source and without a nitrogen source, the glycogen-like substances formed by A. caulinodans ORS571 cells may squeeze the GFP-fused protein aside.…”

Sustaining a Mars Colony through Integration of Single-Cell Oil in Biological Life Support Systems

“…In another study, Arthrospira platensis showed a 2.8-fold increase in carbohydrate accumulation under nitrogen limitation compared to the control sample, while phosphorus limitation in the medium led to a 1.6-fold increase in starch accumulation. [105]. Also, it has been reported that Arthrospira cylindrica grown at low pressure and high CO2 concentrations showed increased carbohydrate content, approaching the protein-tocarbohydrate ratio required by humans [72].…”