Co-production of high density biomass and high-value compounds via two-stage cultivation of Chlorella vulgaris using light intensity and a combination of salt stressors
<p dir="ltr">In this study, the effects of combined stress factors involving light intensity and salinity (NaCl, MgCl<sub>2</sub>, CaCl<sub>2</sub>, and their combinations) on the two-stage cultivation of Chlorella vulgaris for simultaneous production of bioma...
محفوظ في:
| المؤلف الرئيسي: | |
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| مؤلفون آخرون: | , , , , , |
| منشور في: |
2023
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| الموضوعات: | |
| الوسوم: |
إضافة وسم
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| الملخص: | <p dir="ltr">In this study, the effects of combined stress factors involving light intensity and salinity (NaCl, MgCl<sub>2</sub>, CaCl<sub>2</sub>, and their combinations) on the two-stage cultivation of Chlorella vulgaris for simultaneous production of biomass and high-value products, were investigated. The two-stage strategies comprised a 25-day vegetative stage in BG11 medium, followed by a 15-day combined stress stage. During salt stress conditions, the addition of 15 g L<sup>−1</sup> CaCl<sub>2</sub> or 7.5 g L<sup>−1</sup> MgCl<sub>2</sub> / 7.5 g L<sup>−1</sup> CaCl<sub>2</sub> mixture with 140 µmol m<sup>−2</sup> s<sup>−1</sup> light intensity significantly promoted the growth of C. vulgaris achieving maximum biomass productivity of 50.50 ± 0.50 and 50.25 ± 3.25 mg L<sup>−1</sup> d<sup>−1</sup>, respectively. Cultivation of C. vulgaris in a medium containing 7.5 g L<sup>−1</sup> NaCl/ 7.5 g L<sup>−1</sup> CaCl<sub>2</sub> had remarkably increased the lipid content (31.15 ± 1.18%) and lipid productivity (14.55 ± 1.48 mg L<sup>−1</sup> d<sup>−1</sup>). The saturated fatty acids (SFAs) at 39.52–59.29%, monounsaturated fatty acids (MUFAs) at 27.16–35.47%, and polyunsaturated fatty acids (PUFAs) at 7.18–29.97%, were obtained with palmitic (C16:0), oleic (C18:1), stearic (C18:0), and linolenic (C18:3) acids as predominant fatty acids. Cultures supplemented with 5 g L<sup>−1</sup> NaCl / 5 g L<sup>−1</sup> MgCl<sub>2</sub> / 5 g L<sup>−1</sup> CaCl<sub>2</sub> and high light intensity exposure attained consistently high carbohydrate content (52.71 ± 2.50%). The combination of 7.5 g L<sup>−1 </sup>NaCl / 7.5 g L<sup>−1 </sup>MgCl<sub>2</sub> also resulted in a marked increase in the protein content (35.32 ± 2.20%) and total carotenoids (0.31 ± 0.03 μg mL<sup>−1</sup>) as compared to the Controls. The highest antioxidant activity (86.16%) was achieved with a 7.5 g L<sup>−1</sup> NaCl / 7.5 g L<sup>−1</sup> CaCl<sub>2</sub> combination in the growth stage. The antioxidant activities were attributed to the presence of phenolics, flavonoids, and tannins due to the stressed conditions. One of the key benefits of using a combined stress strategy in this study is that if one factor has a low impact on enhancing target metabolites, other factors can compensate.</p><h2>Other Information</h2><p dir="ltr">Published in: Biomass Conversion and Biorefinery<br>License: <a href="https://creativecommons.org/licenses/by/4.0" target="_blank">https://creativecommons.org/licenses/by/4.0</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1007/s13399-023-04442-z" target="_blank">https://dx.doi.org/10.1007/s13399-023-04442-z</a></p> |
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