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Article

Optimization of Industrial-Scale Cultivation Conditions to Enhance the Nutritional Composition of Nontoxic Cyanobacterium Leptolyngbya sp. KIOST-1

by
Won-Kyu Lee
1,2,
Yong-Kyun Ryu
1,2,
Taeho Kim
1,
Areumi Park
1,
Yeon-Ji Lee
1,
Youngdeuk Lee
1,
Ji Hyung Kim
3,
Chulhong Oh
1,2,
Do-Hyung Kang
4,*,† and
Woon-Yong Choi
1,*,†
1
Jeju Bio Research Center, Korea Institute of Ocean Science and Technology (KIOST), 2670, Iljudong-ro, Gujwa-eup, Jeju-si 63349, Republic of Korea
2
Department of Marine Biotechnology, KIOST School, University of Science and Technology (UST), 217, Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea
3
Department of Food Science and Biotechnology, College of Bio-Nano Technology, Gachon University, 1342, Seongnam-daero, Sujeong-gu, Seongnam-si 13120, Republic of Korea
4
Korea Institute of Ocean Science and Technology (KIOST), 385, Haeyang-ro, Yeongdo-gu, Busan 49111, Republic of Korea
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Appl. Sci. 2024, 14(1), 282; https://doi.org/10.3390/app14010282
Submission received: 8 September 2023 / Revised: 8 December 2023 / Accepted: 26 December 2023 / Published: 28 December 2023
(This article belongs to the Special Issue Microalgae: Physiology, Biotechnology, and Industrial Applications)
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Abstract

:
Leptolyngbya sp. KIOST-1 has been proposed as a candidate species for use as a protein supplement due to its high protein content and absence of cytotoxicity. The species has also garnered attention due to the photosynthetic pigments it possesses. However, limited information is available on its cultivation. Therefore, this study was conducted to identify the optimal culture medium and fundamental physiological properties of Leptolyngbya sp. KIOST-1 under various culture conditions. In this study, SOT (Society of Toxicology) medium was confirmed as the optimal culture medium for Leptolyngbya sp. KIOST-1 growth. The biomass production, protein content, and photosynthetic pigment content of Leptolyngbya sp. KIOST-1 were significantly higher in SOT medium. The use of this medium allowed for scaling up from laboratory (10 mL) to pilot (200 L) conditions and industrial-scale outdoor conditions (10,000 L), with the biomass containing over 66% protein. The phytochemical composition of Leptolyngbya sp. KIOST-1 cultured at laboratory and industrial-scales was discovered in this study. Furthermore, we observed that reducing the carbon and nitrogen sources to 1/5 of those supplied by the optimal medium did not significantly affect biomass production, and Leptolyngbya sp. KIOST-1 demonstrated favorable growth capabilities in a salinity range of 10–50 psu and at pH levels of 8.3 to 10.3. The results of this study demonstrate the suitability of Leptolyngbya sp. KIOST-1 for various industrial applications and its adaptability to large-scale cultivation.

1. Introduction

According to a recent United Nations (UN) report, the global population is expected to increase from 7.7 billion to 9.7 billion by 2030, requiring a 60% increase in food production [1]. Proteins are an essential part of human nutrition and are expected to increase in demand as the global population grows. However, the present protein resources may not be sufficient to accommodate future consumption levels, and approximately 1 billion people already experience insufficient dietary protein intake [2]. Although animal-based proteins are considered a high-quality source of essential amino acids, concerns over the inefficiency of livestock processes, ethical issues, and environmental impacts make them unsustainable sources [2,3]. These constraints have prompted the exploration of sustainable and eco-friendly alternatives, particularly protein-rich food sources [4,5].
Recently, microalgae have emerged as sustainable non-animal foods as well as protein supplements [6]. They not only play a role in mitigating global warming by acting as natural carbon sinks, but also have the potential to reduce pressure on arable land and freshwater resources required for terrestrial food production [7,8]. Arthrospira, a representative cyanobacterium also known as Spirulina, is widely consumed as a food supplement and boasts a high protein content, has well-balanced essential amino acids, is low in fat, and possesses essential fatty acids, a high vitamin content, chlorophyll, and phycobiliproteins [9,10,11]. In addition to Arthrospira, numerous species of microalgae and cyanobacteria have been evaluated as food supplements [10].
In 2015, an unknown filamentous cyanobacterium was discovered in Arthrospira ponds and was subsequently named Leptolyngbya sp. KIOST-1 [12]. This strain demonstrated biomass productivity, a high protein content, and an amino acid composition comparable to A. maxima, with no observed cytotoxicity [12]. Moreover, subsequent research identified no putative cyanotoxin genes, and the dried biomass did not exhibit acute toxicity in experimental animals [13,14]. These results suggest that Leptolyngbya sp. KIOST-1 may have potential as a food supplement. Previous studies have confirmed the optimal cultivation temperature (30 °C) for this strain and conducted a growth comparison between Leptolyngbya sp. KIOST-1 and A. maxima cultured in Society of Toxicology (SOT) medium on a laboratory scale [12]. However, this research is insufficient to assess the viability of this strain for industrial production. In the industrial cultivation of microalgae, the key lies in identifying and controlling the cultivation environment to promote the efficient growth of the target species [15]. Furthermore, despite being a cyanobacterium, no analysis of the active photosynthetic pigments (chlorophyll and phycobiliproteins) has been performed. Therefore, this study aimed to identify an optimal culture medium for scaling up cultivation to an industrial scale and analyze its proximate and phytochemical compositions. Additionally, we sought to elucidate growth characteristics in response to variations in carbon, nitrogen, salinity, and pH in the optimal culture medium. The findings of this study contribute to the evaluation of the industrial production potential of Leptolyngbya sp. KIOST-1 and provide fundamental and advantageous information for the industrial-scale cultivation thereof.

2. Materials and Methods

2.1. Strain and Culture Conditions

Leptolyngbya sp. KIOST-1 cells (KCTC 12347BP) were obtained from the Korean Collection for Type Cultures (KCTC) in the Korea Research Institute of Bioscience and Biotechnology (Jeonbuk, Republic of Korea). Cells in the exponential growth phase, which is characterized by rapid and balanced cell division, were used as inoculum seeds for the experiments. All experiments were conducted in a microalgal culture facility with controlled environmental conditions (room temperature, 30 ± 0.5 °C; luminous intensity, 100 ± 0.5 µmol photons m−2 s−1; 12 h light:12 h dark cycle).

2.2. Growth Measurement and Microscopic Observation

The growth of the strain was determined with the biomass concentration (g L−1, dry weight) and a regression curve with optical density (OD) using an ultraviolet-visible spectrophotometer (Optizen POP Bio, Mecasy Co. Ltd., Daejeon, Republic of Korea) at a wavelength of 647 nm. Contamination with other plankton and the morphological features of Leptolyngbya sp. KIOST-1 cells were observed under a light microscope (Eclipse 80i; Nikon Co., Tokyo, Japan). A 10 mL sample was collected and mixed gently, and 2–3 drops were covered with a coverslip on a glass slide. Cells were observed at 200× magnification.

2.3. Cell Harvesting and Bio- and Phytochemical Analysis

Culture samples were harvested by centrifugation at 12,000× g for 30 min at 4 °C. The harvested biomass was frozen and stored at −50 °C for 24 h. The frozen biomass was freeze-dried for 72 h, and the powders were subjected to chemical analyses. The proportions of major components (proteins, carbohydrates, lipids, moisture, and ash) in Leptolyngbya sp. KIOST-1 were quantified following the official method of the Association of Official Analytical Chemists [16]. Specifically, the crude protein and lipid contents were determined through the Kjeldahl assay [17] and Soxhlet method [18], respectively. The moisture content was calculated as the weight difference after drying at 105 °C, and the ash content was determined by weighing the samples before and after a 24 h exposure to 600 °C in a furnace.
Chlorophyll-a and C-phycocyanin were measured using organic solvent (90% acetone) extraction [19] and sodium phosphate buffer methods [20], respectively. Carbohydrate content was determined by calculating the weight difference after accounting for the protein, lipid, moisture, and ash content [21].

2.4. Screening of Culture Medium

Leptolyngbya sp. KIOST-1 cells were cultivated in 10 mL 6-well plates in 11 different types of media (Table 1) for 10 days, and the OD 647 was measured every 2 days. These media are widely used for the growth of cyanobacteria and green microalgae [22,23,24,25,26,27,28,29,30]. The protein, carbohydrate, lipid, moisture, ash, chlorophyll-a, and C-phycocyanin contents of the cells grown in well-grown media were extracted from the dried cells. After growth and biochemical analyses, three media exhibiting high protein and photosynthetic pigment contents and growth performance were selected.

2.5. Scale-Up Cultivations

The selected culture media were prepared for large-scale cultures in 200 L transparent circular cylinders. Industrial scale cultivations were conducted in a 10,000 L open raceway pond (ORP) for two trials (in August and September), and the optimal medium selected through a 200 L culture was used. Subsequently, a 10% seed (based on the total volume) was introduced into the cylinders with an inoculation biomass of 0.2–0.3 g L−1 dry cell weight (Figure 1).
The cultivation facility is located within KIOST (Ansan, Republic of Korea). To prevent the sedimentation of cells, the culture medium was circulated at a speed of 15 rpm using a paddle-wheel. During the cultivation period, we conducted daily measurements of water quality using a YSI meter (MPS556, YSI Incorporated, Chicago, IL, USA). Luminous intensity was measured 0.2 m above the pond surface using a Li-250A digital photometer. On the final day of cultivation, biomass of Leptolyngbya sp. KIOST-1 was harvested using a large-scale tubular centrifuge and stored at −70 °C. Freeze-drying was employed to obtain biomass powder, which was used for further compositional analysis.

2.6. Optimal Culture Medium with Different Experimental Conditions

After identifying the optimal culture medium through screening experiments, nutritional restriction factors, such as carbon and nitrogen sources, and environmental restriction factors, such as salinity and pH, were assessed. The cells were cultivated in 250 mL tissue culture flasks, and the OD 647 was measured every 2 days. This experiment was performed to determine the characteristics of the cyanobacterium, which grows under conditions that likely reflect environmental challenges.
Different carbon and nitrogen sources were designed to provide 10 different concentrations of carbon and nitrogen over the ranges of 0–42 g L−1 and 0–6.25 g L−1, respectively. The control concentrations were 16.8 g L−1 sodium bicarbonate (carbon source) and 2.5 g L−1 sodium nitrate (nitrogen source); these were similar to the optimal culture medium (SOT medium). The experiment was conducted at various salinities and pH values ranging from 10 to 80 psu and pH 8.3–10.3, respectively. The salinity was adjusted using sodium chloride, and the pH was adjusted by adding hydrochloric acid or sodium hydroxide. The salinity and pH values of the control were 15 psu and pH 9.3, respectively, which were similar to those of the SOT medium.

2.7. Statistical Analysis

The data analysis was conducted using the GraphPad Prism 8.4.2 software (GraphPad, San Diego, CA, USA). The mean values ± standard error for each treatment were subjected to statistical analysis, which included the Student’s two-tailed t-test for unpaired data and one-way ANOVA, followed by Tukey’s post hoc test. A significance level of p < 0.05 was applied.

3. Results

3.1. Growth of Leptolyngbya sp. KIOST-1 in Different Media

The biomass concentrations for the plate-scale cultures (10 mL scale) are shown in Figure 2. In the well-grown group, media #1, #5, #6, and #11 provided different nutrients for the growth of Leptolyngbya sp. KIOST-1 (p < 0.05). The highest growth was recorded in medium #11, with a biomass concentration of 2.51 ± 0.02 g L−1. It was followed by media #5, #6, and #1, whose biomass concentrations were 2.11 ± 0.30, 1.94 ± 0.26, and 1.76 ± 0.25 g L−1, respectively, on day 10. Although media #3, #4, and #8 allowed the growth of Leptolyngbya sp. KIOST-1 until day 4, there was no increase in exponential growth thereafter.
Figure 3a shows that cells cultured in four different types of media contained a protein content of over 67%, with the exception of medium #1. Cells cultured in medium #1 had significantly less protein and a higher ash content compared to the other three media. In lipid and carbohydrate contents among all four media, there were no significant differences. As shown in Figure 3b, the levels of C-phycocyanin, a representative cyanobacteria pigment, in the cells cultured in media #11, #5, #1, and #6 were 25.85 ± 0.19, 20.61 ± 0.03, 20.23 ± 0.63, and 18.47 ± 0.10 mg g−1, respectively. The chlorophyll-a levels in the cells cultured in media #11, #6, #1, and #5, were 9.57 ± 0.16, 8.99 ± 0.81, 8.36 ± 0.05, and 7.73 ± 0.01 mg g−1, respectively.

3.2. Scale-Up Cultivation Using Selected Culture Media

The biomass concentrations for the pilot-scale cultures (200 L scale) are shown in Figure 4. The highest growth was recorded in medium #11, with a biomass concentration of 1.16 ± 0.03 g L−1. Although media #5 and #6 exhibited growth similar to that of medium #11 until day 4, there were significant decreases in biomass concentrations from days 6 and 10, respectively (p < 0.05).
Industrial-scale cultivation of Leptolyngbya sp. KIOST-1 was successfully conducted in August and September using medium #11 (SOT medium) within a 10,000 L-scale ORP (Figure 1). In both trials, biomass concentrations exceeding 1.01 gL−1 were achieved. The medium temperature ranged from 30.1 to 33.6 °C and from 27.03 to 31.85 °C, respectively. The luminous intensity varied from 218.50 ± 173.88 µmol photons m−2 s−1 to 166.26 ± 91.37 µmol photons m−2 s−1 (Figure 5a). Salinity was maintained at 13 psu through water replenishment to compensate for daily evaporation. The pH levels increased during cultivation, ranging from 9.31 to 9.85, and from 9.36 to 9.85 (Figure 5b).
As shown in Table 2, the main component, protein, constituted over 66% of the total composition in both cultivation trials, with no significant differences in the proximate composition. Significant differences were observed only in C-phycocyanin and phycoerythrin (p < 0.05).

3.3. Growth of Leptolyngbya sp. KIOST-1 under Different Environmental Regimes

Based on the high protein content and the C-phycocyanin, chlorophyll-a, and biomass concentration in culture medium #11, the SOT medium of Leptolyngbya sp. KIOST-1, we examined the effects of different carbon and nitrogen concentrations on the culture environment.
Figure 6a shows the effect of culturing in 10 different concentrations of sodium bicarbonate as the carbon source, ranging from 0 to 42 g L−1. The growth of Leptolyngbya sp. KIOST-1 cultured in the presence of the most commonly used bicarbonate concentration (that is, 16.8 g L−1 in the regular SOT medium) reached a biomass concentration of 1.96 ± 0.01 g L−1 on the final day of culture. Leptolyngbya sp. KIOST-1 cells cultured in media containing sodium bicarbonate at concentrations ranging from 10.08–42 g L−1 displayed no significant differences in growth between any of the conditions by the final day. Media with lower levels of carbon (that is, 3.36 and 6.72 g L−1 bicarbonate) led to cell death from days 8 and 12, respectively (p < 0.05). The complete limitation of sodium bicarbonate significantly inhibited the growth of Leptolyngbya sp. KIOST-1. Figure 6b shows the effect of culturing in 10 different concentrations of sodium nitrate, ranging from 0 to 6.25 g L−1. The concentration of sodium nitrate in the regular SOT medium was 2.5 g L−1. The lowest biomass concentration was 0.96 ± 0.01 g L−1 under nitrogen-limited conditions on the final day, which was significantly different from that observed on day 4. Microscopic observations revealed fewer filamentous hormogonia and fewer cells under nitrogen-limited conditions than in regular SOT medium (Figure 6b). Except under nitrogen-limited conditions, there were no significant differences in growth.
The SOT medium had a salinity level of 12.0 ± 0.2 psu. Figure 7a shows the effects of different degrees of salinity on growth. On the final day, there were no significant differences in the growth in other culture media at 50 psu. However, at 80 psu, Leptolyngbya sp. KIOST-1 cells did not display any signs of growth.
The effect of pH on Leptolyngbya sp. KIOST-1 cells is shown in Figure 7b. The pH of the SOT medium was 9.3 and was set as the median value for the experiment. There were no significant differences in the growth of cells cultured at different pH values.

4. Discussion

Previous studies have reported that Leptolyngbya sp. KIOST-1 has a high protein content and no cytotoxicity, cyanotoxin-related genes, or acute toxicity, suggesting that it may be a potential protein source candidate [12,13,14]. In this study, we attempted to determine the fundamental physiological characteristics of this species necessary for its cultivation to produce biomass.
We experimentally confirmed the growth of Leptolyngbya sp. KIOST-1 in SOT medium and 3 other media (two media based on BG-11 medium and ATCC 1142 medium) among the 11 different culture media. Cells grown in three of the four media contained approximately 67% protein. This protein content was higher than that suggested in a previous study (51–58% dry matter) on candidate microalgae for protein production [10]. In the analysis of the photosynthetic pigments, we found that the chlorophyll-a content in Leptolyngbya sp. KIOST-1 is similar to that of Arthrospira biomass [31,32]. Although the content of C-phycocyanin was lower than that of Arthrospira [32], it had a phycocyanin content similar to that of another Leptolyngbya sp. which was cultured under field conditions in a previous study (20.2 ± 0.4 mg g−1) [33]. Over the past few years, Arthrospira has been cultivated on a large scale as a valuable source in various industries due to its high protein content and the presence of bioactive compounds, such as C-phycocyanin and chlorophyll-a [34]. Our results suggested that Leptolyngbya sp. KIOST-1 may serve as an alternative to Arthrospira.
One of the main challenges in microalgae biomass production using open raceway ponds (ORPs) is the emergence of other unintended microorganisms, known as contaminants [35]. Contamination by other microalgal species has been widely reported [36,37]. In practice, contamination by several microalgal species disturbs the growth of cells in Arthrospira culture ponds [38]. In previous studies, direct contact, nutrient competition, and allelopathy, which are considered the main biological contamination problems, have been reported in microalgae cultivation [39,40,41]. In more severe cases, contamination causes culture failure due to cross-effects. For Arthrospira consumers, contamination with cyanotoxins, such as microcystine produced by other microalga including Microcystis aeruginosa, is a potentially harmful risk [42,43]. There were no contaminations by other microalgal species or predators during the two industrial cultivation trials in the ORP (Figure 1). These results align with the analysis of the biomass cultured in the laboratory and outdoors, revealing insignificant differences. The reason that Leptolyngbya sp. KIOST-1 is beneficial for outdoor cultivation, similarly to Arthrospira, lies in its growth characteristics. Leptolyngbya sp. KIOST-1 was first isolated in nutrient-depleted SOT medium with a salinity and pH of 13.9 psu and pH 10.3, respectively [12]. As microalgae commonly found in soda lakes exhibit salt tolerance and alkalinity [44], we expected that Leptolyngbya sp. KIOST-1 would also exhibit these characteristics. As shown in Figure 7, this strain exhibits saline tolerance and alkaliphilic properties. Cyanobacteria grow better than other phytoplanktons under alkaline conditions. Although Leptolyngbya sp. KIOST-1 required time to adapt to the high-salinity conditions, similar to other cyanobacterium species [45], it was able to achieve a maximum biomass concentration at up to 50 psu salinity. Species with these characteristics are advantageous for biomass production. The artificial addition of salts and pH adjustment have also been suggested to restrict the growth of contaminants introduced during the culture process in large-scale cultivation [46,47].
We found that Leptolyngbya sp. KIOST-1 cells grew normally under a wide range of nutritional conditions (Figure 6). Carbon and nitrogen are considered major nutrients for cyanobacterial growth and biochemical composition because they are essential for the formation of proteins, chlorophyll, and nucleic acids in cells [48,49]. The main components of the SOT medium are also carbon and nitrogen, provided as sodium bicarbonate and sodium nitrate, respectively. Based on our results, Leptolyngbya sp. KIOST-1 reached the stationary phase without a significant difference in growth, even at 1/5 concentrations of sodium bicarbonate and sodium nitrate in the SOT medium (Figure 6). In our study, cell death in Leptolyngbya sp. KIOST-1 was observed in low-initial-sodium bicarbonate concentrations (Figure 6a) on days 8 and 12. Upon the initiation of cell death, the pH values of the media exhibited a sharp increase up to 11.0. Such cell death has also been observed in other Leptolyngbya sp. and Arthrospira cultures [50,51]. This sharp increase in pH was related to bicarbonate consumption. Although carbon dioxide (CO2) is considered a major carbon source for microalgal growth, most cyanobacteria actively take up bicarbonate (HCO3−) [52]. In general, HCO3− accumulates in the cytoplasm and is converted into CO2 shortly before photosynthesis [52]. In addition, it leads to an increase in the pH of the culture medium because hydroxide ions (OH−) are used from HCO3− as cells grow. In this situation, residual HCO3− in the culture medium reacts with OH− to form carbonate (CO32−) and acts as a pH buffer to slowly increase the pH [53]. At initial bicarbonate conditions below 6.72 g L−1, the pH buffer mechanism did not work properly. This interpretation can explain the sharp increase in pH as well as the cell death. Therefore, although Leptolyngbya sp. KIOST-1 is capable of sufficient growth at low carbon concentrations, caution should be exercised to prevent culture failure. While it has been confirmed that significant differences in biomass production can occur even with low concentrations of carbon and nitrogen sources, this study did not include a composition analysis in this regard. Therefore, it could be suggested to reduce nutrient concentrations for economical biomass production, but any resulting changes in composition should be investigated and confirmed.
Interestingly, our results demonstrated that the strain continued to grow until the final day under nitrogen-limited conditions (Figure 6b). Most cyanobacteria, including both heterocystous and non-heterocystous cyanobacteria, can fix biological nitrogen through a process in which atmospheric nitrogen (N2) is converted into a usable form [54]. Heterocystous cyanobacteria are capable of carrying out N2 fixation even in aerobic conditions. This process involves the differentiation of approximately 5–10% of their cells into specialized units known as heterocytes. These heterocytes create an environment conducive to the activity of nitrogenase, the enzyme responsible for N2 fixation [54]. Heterocytes have not been observed in Leptolyngbya sp. KIOST-1 [12], which is a non-heterocystous cyanobacterium, suggesting that it employs various N2 fixation mechanisms for growth [54]. We could not definitively confirm the mechanisms using only these results. Non-heterocystous Thermoleptolyngbya sp., which has 97.9% similarity with Leptolyngbya sp. KIOST-1 in terms of the dinitrogenase reductase gene (nifH), display light- and temperature-dependent N2 fixation [55]. However, Leptolyngbya sp. KIOST-1 exhibited abnormal growth characteristics, such as low biomass concentration and short hormogonia (Figure 6b), under nitrogen-limited conditions; a similar phenomenon has been observed in Oscillatoria willei, another non-heterocystous cyanobacterium species, which was reported in a previous study [56]. The cost of growth media is a significant factor in large-scale cultivation [15]. Therefore, strains that can grow under low-carbon and -nitrogen conditions, and even under nitrogen-limited conditions, have a competitive advantage.

5. Conclusions

In conclusion, the optimal culture medium for industrial scale cultivation of Leptolyngyba sp. KIOST-1 was SOT medium. As confirmed in this study, Leptolyngbya sp. KIOST-1 cells possess a protein content of 67% or more, and their photosynthetic pigment content is similar to that of Arthrospira cells. Moreover, Leptolyngbya sp. KIOST-1 was confirmed to have potential to be scaled up for commercial cultivation through successful 200 L- and 10,000 L-scale cultivations. The high protein content and presence of bioactive pigments in this strain make it a promising candidate for food supplements and functional food sources. Furthermore, this study reports on the growth of Leptolyngbya sp. KIOST-1 cells under various experimental culture conditions. We found that this species survives in a wide range of salinities, pH values, and nutritional conditions. Therefore, we propose that Leptolyngbya sp. KIOST-1 is a promising candidate for various industrial applications.

Author Contributions

Conceptualization, W.-K.L. and D.-H.K.; methodology, W.-K.L., Y.-K.R. and W.-Y.C.; software, W.-K.L.; validation, A.P. and Y.-J.L.; formal analysis, Y.L. and C.O.; investigation, D.-H.K.; resources, C.O.; data curation, W.-K.L. and T.K.; writing—original draft preparation, W.-K.L.; writing—review and editing, W.-K.L., J.H.K., C.O., D.-H.K. and W.-Y.C.; visualization, W.-K.L. and Y.-K.R. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by Korea Institute of Marine Science & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (20220380). This research was funded by the Korea Institute of Ocean Science and Technology Project (PEA0125).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Department of Economic and Social Affairs, U.N. World Population Prospects 2019: Highlights. Available online: https://population.un.org/wpp/Publications/Files/WPP2019_Highlights.pdf (accessed on 8 April 2020).
  2. Wu, G.; Fanzo, J.; Miller, D.D.; Pingali, P.; Post, M.; Steiner, J.L.; Thalacker-Mercer, A.E. Production and supply of high-quality food protein for human consumption: Sustainability, challenges, and innovations. Ann. N.Y. Acad. Sci. 2014, 1321, 1–19. [Google Scholar] [CrossRef] [PubMed]
  3. Miller, B.D.D.; Welch, R.M. Food system strategies for preventing micronutrient malnutrition. Food Policy 2013, 42, 115–128. [Google Scholar] [CrossRef]
  4. Roohinejad, S.; Koubaa, M.; Barba, F.J.; Saljoughian, S.; Amid, M.; Greiner, R. Application of seaweeds to develop new food products with enhanced shelf-life, quality and health-related beneficial properties. Food Res. Int. 2017, 99, 1066–1083. [Google Scholar] [CrossRef] [PubMed]
  5. Hosseinkhani, N.; McCauley, J.I.; Ralph, P.J. Key challenges for the commercial expansion of ingredients from algae into human food products. Algal Res. 2022, 64, 102696. [Google Scholar] [CrossRef]
  6. Geada, P.; Moreira, C.; Silva, M.; Nunes, R.; Madureira, L.; Rocha, C.M.R.; Pereira, R.N.; Vicente, A.A.; Teixeira, J.A. Algal proteins: Production strategies and nutritional and functional properties. Bioresour. Technol. 2021, 332, 125125. [Google Scholar] [CrossRef] [PubMed]
  7. Kusmayadi, A.; Leong, Y.K.; Yen, H.W.; Huang, C.Y.; Chang, J.S. Microalgae as sustainable food and feed sources for animals and humans—Biotechnological and environmental aspects. Chemosphere 2021, 271, 129800. [Google Scholar] [CrossRef] [PubMed]
  8. Milledge, J.J. Commercial application of microalgae other than as biofuels: A brief review. Rev. Environ. Sci. Biotechnol. 2011, 10, 31–41. [Google Scholar] [CrossRef]
  9. Vonshak, A.; Richmond, A. Mass production of the blue-green alga Spirulina: An overview. Biomass 1988, 15, 233–247. [Google Scholar] [CrossRef]
  10. Becker, E.W. Micro-algae as a source of protein. Biotechnol. Adv. 2007, 25, 207–210. [Google Scholar] [CrossRef]
  11. Caporgno, M.P.; Mathys, A. Trends in microalgae incorporation into innovative food products with potential health benefits. Front. Nutr. 2018, 5, 58. [Google Scholar] [CrossRef]
  12. Kim, J.H.; Choi, W.; Jeon, S.M.; Kim, T.; Park, A.; Kim, J.; Heo, S.J.; Oh, C.; Shim, W.B.; Kang, D.H. Isolation and characterization of Leptolyngbya sp. KIOST-1, a basophilic and euryhaline filamentous cyanobacterium from an open paddle-wheel raceway Arthrospira culture pond in Korea. J. Appl. Microbiol. 2015, 119, 1597–1612. [Google Scholar] [CrossRef] [PubMed]
  13. Kim, J.H.; Kang, D.H. Draft genome sequence of Leptolyngbya sp. KIOST-1, a filamentous cyanobacterium with biotechnological potential for alimentary purposes. Genome Announc. 2016, 4, 10–1128. [Google Scholar] [CrossRef] [PubMed]
  14. Lee, Y.; Kim, T.; Lee, W.K.; Ryu, Y.K.; Kim, J.H.; Jeong, Y.; Park, A.; Lee, Y.J.; Oh, C.; Kang, D.H. The first report to evaluate safety of cyanobacterium Leptolyngbya sp. KIOST-1 for use as a food ingredient: Oral acute toxicity and genotoxicity study. J. Microbiol. Biotechnol. 2021, 31, 290–297. [Google Scholar] [CrossRef] [PubMed]
  15. Borowitzka, M.A.; Vonshak, A. Scaling up microalgal cultures to commercial scale. Eur. J. Phycol. 2017, 52, 407–418. [Google Scholar] [CrossRef]
  16. AOAC. Official Methods of Analysis of the Association of Analytical Chemists, 19th ed.; Association of Official Analytical Chemists: Washington, DC, USA, 2005. [Google Scholar]
  17. Bradstreet, R.B. Kjeldahl method for organic nitrogen. Anal. Chem. 1954, 26, 185–187. [Google Scholar] [CrossRef]
  18. Li, Y.; Ghasemi Naghdi, F.; Garg, S.; Adarme-Vega, T.C.; Thurecht, K.J.; Ghafor, W.A.; Tannock, S.; Schenk, P.M. A comparative study: The impact of different lipid extraction methods on current microalgal lipid research. Microb. Cell Fact. 2014, 13, 14. [Google Scholar] [CrossRef] [PubMed]
  19. Ritchie, R.J. Consistent sets of spectrophotometric chlorophyll equations for acetone, methanol and ethanol solvents. Photosynth. Res. 2006, 89, 27–41. [Google Scholar] [CrossRef]
  20. Bennett, A.; Bogorad, L. Complementary chromatic adaptation in a filamentous blue-green alga. J. Cell Biol. 1973, 58, 419–435. [Google Scholar] [CrossRef]
  21. James, C.S. Analytical Chemistry of Foods; Springer Science and Business Media: Berlin/Heidelberg, Germany, 1996. [Google Scholar]
  22. Allen, M.B.; Arnon, D.I. Studies on nitrogen-fixing blue-green algae. I. Growth and nitrogen fixation by Anabaena cylindrica Lemm. Plant Physiol. 1955, 30, 366–372. [Google Scholar] [CrossRef]
  23. Williams, S.K.; Kempton, J.; Wilde, S.B.; Lewitus, A. A novel epiphytic cyanobacterium associated with reservoirs affected by avian vacuolar myelinopathy. Harmful Algae 2007, 6, 343–353. [Google Scholar] [CrossRef]
  24. Atlas, R.M. Handbook of Microbiological Media; CRC Press: Boca Raton, FL, USA, 2004. [Google Scholar]
  25. Stanier, R.Y.; Deruelles, J.; Rippka, R.; Herdman, M.; Waterbury, J.B. Generic assignments, strain histories and properties of pure cultures of cyanobacteria. Microbiology 1979, 111, 1–61. [Google Scholar] [CrossRef]
  26. Castenholz, R.W. Culturing methods for cyanobacteria. In Methods in Enzymol; Academic Press: Cambridge, MA, USA, 1988; Volume 167, pp. 68–93. [Google Scholar]
  27. Chu, S.P. The influence of the mineral composition of the medium on the growth of planktonic algae: Part I. Methods and culture media. J. Ecol. 1942, 30, 284–325. [Google Scholar] [CrossRef]
  28. David, K.A.V.; Thomas, J. Extracellular polypeptides of Anabaena L-31: Evidence for their role in regulation of heterocyst formation. J. Biosci. 1979, 1, 447–455. [Google Scholar] [CrossRef]
  29. Corbett, L.L.; Parker, D.L. Viability of lyophilized cyanobacteria (blue-green algae). Appl. Environ. Microbiol. 1976, 32, 777–780. [Google Scholar] [CrossRef] [PubMed]
  30. Ogawa, T. Studies on the growth of Spirulina platensis (I). On the pure culture of Spirulina platensis. J. Ferment. Tecnol. 1970, 48, 361–367. [Google Scholar]
  31. Marzorati, S.; Schievano, A.; Idà, A.; Verotta, L. Carotenoids, Chlorophylls and Phycocyanin from Spirulina: Supercritical CO2 and Water Extraction Methods for Added Value Products Cascade. Green Chem. 2020, 22, 187–196. [Google Scholar] [CrossRef]
  32. Kim, T.; Choi, W.-S.; Ye, B.-R.; Heo, S.-J.; Oh, D.; Kim, S.; Choi, K.-S.; Kang, D.-H. Cultivating Spirulina maxima: Innovative Approaches. In Cyanobacteria; Intech: London, UK, 2018; Volume 61, pp. 61–83. [Google Scholar]
  33. Schipper, K.; Das, P.; Al Muraikhi, M.; AbdulQuadir, M.; Thaher, M.I.; Al Jabri, H.M.S.J.; Wijffels, R.H.; Barbosa, M.J. Outdoor scale-up of Leptolyngbya sp.: Effect of light intensity and inoculum volume on photoinhibition and -oxidation. Biotechnol. Bioeng. 2021, 118, 2368–2379. [Google Scholar] [CrossRef]
  34. Thevarajah, B.; Nishshanka, G.K.S.H.; Premaratne, M.; Nimarshana, P.H.V.; Nagarajan, D.; Chang, J.-S.; Ariyadasa, T.U. Large-scale production of Spirulina-based proteins and c-phycocyanin: A biorefinery approach. Biochem. Eng. J. 2022, 185, 108541. [Google Scholar] [CrossRef]
  35. Christenson, L.; Sims, R. Production and harvesting of microalgae for wastewater treatment, biofuels, and bioproducts. Biotechnol. Adv. 2011, 29, 686–702. [Google Scholar] [CrossRef]
  36. Mooij, P.R.; Stouten, G.R.; van Loosdrecht, M.C.M.; Kleerebezem, R. Ecology-Based Selective Environments as Solution to Contamination in Microalgal Cultivation. Curr. Opin. Biotechnol. 2015, 33, 46–51. [Google Scholar] [CrossRef]
  37. Piazzi, L.; Ceccherelli, G. Effects of competition between two introduced Caulerpa. Mar. Ecol. Prog. Ser. 2002, 225, 189–195. [Google Scholar] [CrossRef]
  38. Yuan, D.; Zhan, X.; Wang, M.; Wang, X.; Feng, W.; Gong, Y.; Hu, Q. Biodiversity and Distribution of Microzooplankton in Spirulina (Arthrospira) platensis Mass Cultures Throughout China. Algal Res. 2018, 30, 38–49. [Google Scholar] [CrossRef]
  39. Twiner, M.J.; Dixon, S.J.; Trick, C.G. Toxic effects of Heterosigma akashiwo do not appear to be mediated by hydrogen peroxide. Limnol. Oceanogr. 2001, 46, 1400–1405. [Google Scholar] [CrossRef]
  40. Twiner, M.J.; Chidiac, P.; Dixon, S.J.; Trick, C.G. Extracellular organic compounds from the ichthyotoxic red tide alga Heterosigma akashiwo elevate cytosolic calcium and induce apoptosis in Sf9 cells. Harmful Algae 2005, 4, 789–800. [Google Scholar] [CrossRef]
  41. Yamasaki, Y.; Nagasoe, S.; Matsubara, T.; Shikata, T.; Shimasaki, Y.; Oshima, Y.; Honjo, T. Growth inhibition and formation of morphologically abnormal cells of Akashiwo sanguinea (Hirasaka) G. Hansen et Moestrup by cell contact with Cochlodinium polykrikoides Margalef. Mar. Biol. 2007, 152, 157–163. [Google Scholar] [CrossRef]
  42. Gilroy, D.J.; Kauffman, K.W.; Hall, R.A.; Huang, X.; Chu, F.S. Assessing potential health risks from microcystin toxins in blue-green algae dietary supplements. Environ. Health Perspect. 2000, 108, 435–439. [Google Scholar] [CrossRef] [PubMed]
  43. Jiang, Y.; Xie, P.; Chen, J.; Liang, G. Detection of the hepatotoxic microcystins in 36 kinds of cyanobacteria Spirulina food products in China. Food Addit. Contam. 2008, 25, 885–894. [Google Scholar] [CrossRef]
  44. Richmond, A. Handbook of Microalgal Culture: Biotechnology and Applied Phycology; Wiley Online Library: Hoboken, NJ, USA, 2004; Volume 577. [Google Scholar]
  45. Hotos, G.N.; Avramidou, D.; Samara, A. The effect of salinity and light intensity on the batch cultured cyanobacteria Anabaena sp. and Cyanothece sp. Hydrobiology 2022, 1, 278–287. [Google Scholar] [CrossRef]
  46. Vadlamani, A.; Viamajala, S.; Pendyala, B.; Varanasi, S. Cultivation of microalgae at extreme alkaline pH conditions: A novel approach for biofuel production. ACS Sustain. Chem. Eng. 2017, 5, 7284–7294. [Google Scholar] [CrossRef]
  47. Lee, W.K.; Ryu, Y.K.; Choi, W.Y.; Kim, T.; Park, A.; Lee, Y.J.; Jeong, Y.; Lee, C.G.; Kang, D.H. Year-round cultivation of Tetraselmis sp. for essential lipid production in a semi-open raceway system. Mar. Drugs 2021, 19, 314. [Google Scholar] [CrossRef]
  48. Yodsuwan, N.; Sawayama, S.; Sirisansaneeyakul, S. Effect of nitrogen concentration on growth, lipid production and fatty acid profiles of the marine diatom Phaeodactylum tricornutum. Agric. Nat. Resour. 2017, 51, 190–197. [Google Scholar] [CrossRef]
  49. Khazi, M.I.; Demirel, Z.; Dalay, M.C. Evaluation of growth and phycobiliprotein composition of cyanobacteria isolates cultivated in different nitrogen sources. J. Appl. Phycol. 2018, 30, 1513–1523. [Google Scholar] [CrossRef]
  50. Zhu, C.; Zhai, X.; Wang, J.; Han, D.; Li, Y.; Xi, Y.; Tang, Y.; Chi, Z. Large-scale cultivation of Spirulina in a floating horizontal photobioreactor without aeration or an agitation device. Appl. Microbiol. Biotechnol. 2018, 102, 8979–8987. [Google Scholar] [CrossRef] [PubMed]
  51. Zhu, C.; Che, J.; Zhai, X.; Wang, J.; Kong, F.; Chi, Z. Cost-effective and efficient production of carbohydrates from an alkalihalophilic Leptolyngbya sp. in a photobioreactor with periodical mixing. ACS Sustain. Chem. Eng. 2020, 8, 15310–15316. [Google Scholar] [CrossRef]
  52. Price, G.D.; Badger, M.R.; Woodger, F.J.; Long, B.M. Advances in understanding the cyanobacterial CO2-concentrating-mechanism (CCM): Functional components, Ci transporters, diversity, genetic regulation and prospects for engineering into plants. J. Exp. Bot. 2008, 59, 1441–1461. [Google Scholar] [CrossRef] [PubMed]
  53. Chi, Z.; Elloy, F.; Xie, Y.; Hu, Y.; Chen, S. Selection of microalgae and cyanobacteria strains for bicarbonate-based integrated carbon capture and algae production system. Appl. Biochem. Biotechnol. 2014, 172, 447–457. [Google Scholar] [CrossRef]
  54. Bergman, B.; Gallon, J.R.; Rai, A.N.; Stal, L.J. N2 fixation by non-heterocystous cyanobacteria. FEMS Microbiol. Rev. 1997, 19, 139–185. [Google Scholar] [CrossRef]
  55. Yoon, K.S.; Nguyen, N.T.; Tran, K.T.; Tsuji, K.; Ogo, S. Nitrogen fixation genes and nitrogenase activity of the non-heterocystous cyanobacterium Thermoleptolyngbya sp. O-77. Microbes Environ. 2017, 32, 324–329. [Google Scholar] [CrossRef]
  56. Kumar Saha, S.; Uma, L.; Subramanian, G. Nitrogen stress induced changes in the marine cyanobacterium Oscillatoria willei BDU 130511. FEMS Microbiol. Ecol. 2003, 45, 263–272. [Google Scholar] [CrossRef]
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Figure 1. Photographs of the 10,000 L-scale microalgae cultivation facility, tubular centrifuge, and harvested biomass.
Figure 1. Photographs of the 10,000 L-scale microalgae cultivation facility, tubular centrifuge, and harvested biomass.
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Figure 2. Growth of Leptolyngbya sp. KIOST-1 cultured in 11 different media for 10 days (mean ± standard error, n = 2). The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05. The black numbers on the image displaying the culturing plates indicate the media number.
Figure 2. Growth of Leptolyngbya sp. KIOST-1 cultured in 11 different media for 10 days (mean ± standard error, n = 2). The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05. The black numbers on the image displaying the culturing plates indicate the media number.
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Figure 3. (a) Proximate and (b) phytochemical pigment compositions of Leptolyngbya sp. KIOST-1 cells cultured in four different media (mean ± standard error, n = 3). Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05.
Figure 3. (a) Proximate and (b) phytochemical pigment compositions of Leptolyngbya sp. KIOST-1 cells cultured in four different media (mean ± standard error, n = 3). Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05.
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Figure 4. Growth of Leptolyngbya sp. KIOST-1 cultured in three different media on a 200 L scale (mean ± standard error, n = 2). The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05. The white and black numbers on the image displaying the culturing cylinders indicate days of culture and media number, respectively.
Figure 4. Growth of Leptolyngbya sp. KIOST-1 cultured in three different media on a 200 L scale (mean ± standard error, n = 2). The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05. The white and black numbers on the image displaying the culturing cylinders indicate days of culture and media number, respectively.
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Figure 5. (a) Water temperature (left y-axis) and luminous intensity (right y-axis) and (b) salinity (left y-axis) and pH level (right y-axis) in Leptolyngbya sp. KIOST-1 culture pond during two cultivation trials.
Figure 5. (a) Water temperature (left y-axis) and luminous intensity (right y-axis) and (b) salinity (left y-axis) and pH level (right y-axis) in Leptolyngbya sp. KIOST-1 culture pond during two cultivation trials.
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Figure 6. Growth of Leptolyngbya sp. KIOST-1 in modified SOT media containing 10 different concentrations of (a) sodium bicarbonate and (b) sodium nitrate as carbon and nitrogen sources, respectively (mean ± standard error, n = 3). The control concentrations were 16.8 g L−1 sodium bicarbonate and 2.5 g L−1 sodium nitrate, which are similar to those of SOT medium. The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05. The black letters on the microscopic images indicate sodium carbonate and sodium nitrate concentrations. Scale bar, 50 μm.
Figure 6. Growth of Leptolyngbya sp. KIOST-1 in modified SOT media containing 10 different concentrations of (a) sodium bicarbonate and (b) sodium nitrate as carbon and nitrogen sources, respectively (mean ± standard error, n = 3). The control concentrations were 16.8 g L−1 sodium bicarbonate and 2.5 g L−1 sodium nitrate, which are similar to those of SOT medium. The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05. The black letters on the microscopic images indicate sodium carbonate and sodium nitrate concentrations. Scale bar, 50 μm.
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Figure 7. Growth of Leptolyngbya sp. KIOST-1 cultured in (a) six different salinity conditions and (b) five different pH conditions (mean ± standard error, n = 3). The salinity and pH values of the control were 15 psu and pH 9.3, respectively, which are similar to those of the SOT medium. The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05.
Figure 7. Growth of Leptolyngbya sp. KIOST-1 cultured in (a) six different salinity conditions and (b) five different pH conditions (mean ± standard error, n = 3). The salinity and pH values of the control were 15 psu and pH 9.3, respectively, which are similar to those of the SOT medium. The y-axis shows the biomass concentration, and the x-axis shows the days of culture. Significant differences are represented using different lowercase letters. “ns” means “there is no significant difference” as determined by one-way analysis of variance (ANOVA) with post hoc Tukey’s test, where p < 0.05.
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Table 1. Eleven media for cultivation of Leptolyngbya sp. KIOST-1.
Table 1. Eleven media for cultivation of Leptolyngbya sp. KIOST-1.
NumberCulture MediaNoteReference
1ATCC 1142 [22]
2CRBIP 1538 -
3ATCC 819Blue-green nitrogen-fixing medium[23]
4ATCC 1077Nitrogen-fixing marine medium[24]
5ATCC 616BG-11[25]
6CRBIP 1547BG-11 + NaHCO3-
7Castenholtz D [26]
8ATCC 341Chu’s #10[27]
9Cyanophycean [28]
10Parker’s J (Jansen) [29]
11SOT [30]
Table 2. Proximate and phytochemical pigment compositions of Leptolyngbya sp. KIOST-1 cells cultured in open raceway pond (mean ± standard error, n = 3). Significant differences are represented using different lowercase letters as determined by two-tailed Student’s t-test, p < 0.05.
Table 2. Proximate and phytochemical pigment compositions of Leptolyngbya sp. KIOST-1 cells cultured in open raceway pond (mean ± standard error, n = 3). Significant differences are represented using different lowercase letters as determined by two-tailed Student’s t-test, p < 0.05.
1st Trial2nd Trial
Culture period (days)1313
Final biomass production (g L−1)1.21 ± 0.121.01 ± 0.08
 Proximate composition (%)
Protein66.15 ± 0.3067.38 ± 0.58
Lipid12.82 ± 0.1811.98 ± 0.32
Carbohydrate7.69 ± 1.219.19 ± 0.83
Moisture2.45 ± 0.482.12 ± 0.06
Ash10.89 ± 1.219.33 ± 0.12
 Photosynthetic pigments (mg g−1)
C-phycocyanin28.88 ± 0.69 a22.87 ± 0.02 b
Allo-phycocyanin17.59 ± 2.838.91 ± 3.28
Phycoerythrin8.07 ± 0.96 a3.03 ± 0.85 b
Chlorophyll-a6.85 ± 0.515.62 ± 0.31
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Lee, W.-K.; Ryu, Y.-K.; Kim, T.; Park, A.; Lee, Y.-J.; Lee, Y.; Kim, J.H.; Oh, C.; Kang, D.-H.; Choi, W.-Y. Optimization of Industrial-Scale Cultivation Conditions to Enhance the Nutritional Composition of Nontoxic Cyanobacterium Leptolyngbya sp. KIOST-1. Appl. Sci. 2024, 14, 282. https://doi.org/10.3390/app14010282

AMA Style

Lee W-K, Ryu Y-K, Kim T, Park A, Lee Y-J, Lee Y, Kim JH, Oh C, Kang D-H, Choi W-Y. Optimization of Industrial-Scale Cultivation Conditions to Enhance the Nutritional Composition of Nontoxic Cyanobacterium Leptolyngbya sp. KIOST-1. Applied Sciences. 2024; 14(1):282. https://doi.org/10.3390/app14010282

Chicago/Turabian Style

Lee, Won-Kyu, Yong-Kyun Ryu, Taeho Kim, Areumi Park, Yeon-Ji Lee, Youngdeuk Lee, Ji Hyung Kim, Chulhong Oh, Do-Hyung Kang, and Woon-Yong Choi. 2024. "Optimization of Industrial-Scale Cultivation Conditions to Enhance the Nutritional Composition of Nontoxic Cyanobacterium Leptolyngbya sp. KIOST-1" Applied Sciences 14, no. 1: 282. https://doi.org/10.3390/app14010282

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