Effect of pH on growth and lipid accumulation kinetics of the microalga Chlorella vulgaris grown heterotrophically under sulfur limitation

Sakarika, Myrsini; Kornaros, Michael

doi:10.1016/j.biortech.2016.08.033

Cited by 100 publications

(26 citation statements)

References 28 publications

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“…It has been previously reported that the pH of the culture medium can significantly affect the growth of some microalgae. For example in Chlorella vulgaris , the stationary phase was reached by the 10th day of cultivation in a pH range from 5.0 to 7.0, while for pH 7.5 and 8.0 the growth stopped by the 8th day . Using Nannochloropsis salina , the maximum cell growth was observed at pH 8.0 (95.6 × 10 6 cells mL −1 ) and 9.0 (92.8 × 10 6 cells mL −1 ) at around 21 days .…”

Section: Resultsmentioning

confidence: 98%

“…However, at pH 8.5 a slower growth was observed in the culture resulting in a 93% reduction when compared with the control experiment (Figure ). Sakarika and Kornaros reported that under acidic conditions (pH 3.0–5.0) and alkaline conditions (pH 8.3–9.0) the growth of C. vulgaris was reduced 27.3–55.2% and 46.1–34.2%, respectively, when compared with the control experiment where the pH was set to 6.9; at pH values of 7.5 and 8.0 the growth exceeded the control values by 20–25%. Our results might suggest that at pH above 7.8 there is an inadequate electron transport, or H + gradient, to establish the function of the complex ATP synthase for ATP formation that is used for cellular growth .…”

Section: Discussionmentioning

confidence: 97%

“…Bartley et al showed that Nannochloropsis salina reached 24.75% of lipid accumulation at pH 8 while the un‐buffered control reached 21.8%. Sakarika and Kornaros reported the growth of Chlorella vulgaris in a culture under sulfur limitation at pH 7.5 and 8.0 for 16 days, the culture at pH 7.5 reached the highest lipid accumulation (53.43% dcw); while in the culture at pH 8.0 the lipid content was reduced to 34.78% dcw. In the same way, the microalga Scenedesmus abundans showed higher lipid content (26.20 ± 0.4% dcw) at pH 6, while at pH 5 it was reduced to17.30 ± 0.2% dcw …”

Section: Discussionmentioning

confidence: 99%

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pH effects on the lipid and fatty acids accumulation in Chlamydomonas reinhardtii

Ochoa-Alfaro

Gaytán-Luna

González‐Ortega

et al. 2019

Biotechnology Progress

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pH variations influence the delivery of essential nutrients and CO2 solubility, which impact algae metabolism. In this study the microalgal growth and chlorophyll, lipid, and fatty acids content; along with the expression of some genes implicated in the biosynthesis of lipids were examined in Chlamydomonas reinhardtii subjected to pH values of 7.0, 7.8, and 8.5. At pH 7.8 an increase in cell growth was observed with a significant accumulation of chlorophyll (1.75‐fold) when compared with growth at pH 7, while at pH 8.5 a sharp decrease in both parameters was observed when compared with the other pH values tested. Lipid content increased 3.0 (14.81% of dry cell weight, dcw) and 2.3 times (11.43% dcw) at pH 7.8 and 8.5, respectively, when compared with the experiment at pH 7 (4.97% dcw). The compositions of major fatty acids in the strains growing at pH 7.0, 7.8, or 8.5 were 25.7, 28.0, and 32.1% for palmitic acid; 17.3, 14.7, and 25.7% for oleic acid; and 9.8, 12.1, and 4.6% for linoleic acid; respectively. qRT‐PCR analysis showed that the transcripts of ß‐carboxyltransferase, Acyl carrier protein 1, acyl‐ACP thiolase 1, acyl‐sn‐glycerol‐3‐phosphate acyltransferase, and diacylglycerol acyl transferase isoform 3 were significantly induced at pH 7.8 when compared with the other two pH conditions. These results indicate that the induction of genes implicated in the early and final steps of lipid biosynthesis contributes to their accumulation in the stationary phase. Our research suggests that a pH of 7.8 might be ideal to maximize growth and lipid accumulation.

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Section: Resultsmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

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pH effects on the lipid and fatty acids accumulation in Chlamydomonas reinhardtii

Ochoa-Alfaro

Gaytán-Luna

González‐Ortega

et al. 2019

Biotechnology Progress

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“…The buffer system is necessary for sustaining the required pH, particularly at neutral or mildly alkaline pH (7.5-8.0), in the microalgal culture medium because high or low pH is detrimental for the vegetative growth as well as the production of value-added products by microalgae [38,39]. In general, Tris and HEPES have been widely used as a buffer for microalgae cultivation [12,29], which are very costly.…”

Section: Discussionmentioning

confidence: 99%

Microalgal-Based Carbon Sequestration by Converting LNG-Fired Waste CO2 into Red Gold Astaxanthin: The Potential Applicability

et al. 2019

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The combinatorial approach of anthropogenic activities and CO2 sequestration is becoming a global research trend to alleviate the average global temperature. Although microalgae have been widely used to capture CO2 from industrial flue gas, the application of bioproducts was limited to bioenergy due to the controversy over the quality and safety of the products in the food and feed industry. Herein, the waste CO2 emitted from large point sources was directly captured using astaxanthin-hyperproducing microalgae Haematococcus pluvialis. Astaxanthin production was successfully carried out using the hypochlorous acid water-based axenic culture process under highly contamination-prone outdoor conditions. Consequently, after 36 days of autotrophic induction, the productivity of biomass and astaxanthin of H. pluvialis (the mutant) reached 0.127 g L−1 day−1 and 5.47 mg L−1 day−1 under high summer temperatures, respectively, which was 38% and 48% higher than that of wild type cell. After grinding the wet astaxanthin-enriched biomass, the extract was successfully approved by compliance validation testing from Korea Food and Drug Administration. The assorted feed improved an immune system of the poultry without causing any side effects. The flue gas-based bioproducts could certainly be used for health functional food for animals in the future.

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“…The energy consumption of the automatic pH controller contributed to the additional energy consumption of PBR1. The pH of PBR1 was always kept constant at 7.5; however, the pH of PBR3 was maintained manually from 7.0 to 8.0 because some studies reported that for C. vulgaris showed satisfactory results in this range [22,23]. Air pumps, the only energy-consuming equipment of outdoor PBRs, were accounted for less than 0.5% of the total energy in both PBR1 and PBR2.…”

Section: Energy Consumptionmentioning

confidence: 99%

Indoor and outdoor cultivation of Chlorella vulgaris and its application in wastewater treatment in a tropical city—Bangkok, Thailand

Sarker

Salam

2019

SN Appl. Sci.

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This study was carried out to assess the effectiveness of algal growth cultivated in photobioreactors (PBRs) in different conditions in a tropical environment, i.e., indoor and outdoor conditions with wastewater in Bangkok. The PBRs were inoculated with pure Chlorella vulgaris, and the cultivation was conducted in housing state wastewater. The productivity of C. vulgaris was found to be 0.0960 g/l/d in a pH-controlled outdoor PBR with pH in between 7.0 and 8.0, 0.0618 g/l/d in outdoor PBR with no control, and 0.0131 g/l/d in indoor pH-controlled PBR (with a fixed pH of 7.5). Chlorella vulgaris did not show growth in indoor PBR with no pH control. Indoor PBRs consumed 232 to 270 times more energy and needed 25 to 57 times more capital cost, and 3.8 to 16.8 times more operating cost than that of outdoor PBRs. Outdoor PBRs showed better nutrient removal efficiency of housing state wastewater than that of the wastewater treatment plant, i.e., 100% removal of biological oxygen demand, chemical oxygen demand, total phosphorus and more than 96% removal of total nitrogen; However, required time and energy consumption were more in outdoor PBRs. The possibility of improving the process performance by controlling pH, by supplying CO 2 from additional source, and by supplying continuous aeration appears as an attractive option. Although precautions should be taken for CO 2 supply, high concentration CO 2 caused a significant drop in pH and an increase of total dissolved solids. Light transmission efficiency of PBR material polyethylene terephthalate material was 85.45% to 92.08%, and efficiency decreased with the increase in light intensity.

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Effect of pH on growth and lipid accumulation kinetics of the microalga Chlorella vulgaris grown heterotrophically under sulfur limitation

Cited by 100 publications

References 28 publications

pH effects on the lipid and fatty acids accumulation in Chlamydomonas reinhardtii

pH effects on the lipid and fatty acids accumulation in Chlamydomonas reinhardtii

Microalgal-Based Carbon Sequestration by Converting LNG-Fired Waste CO2 into Red Gold Astaxanthin: The Potential Applicability

Indoor and outdoor cultivation of Chlorella vulgaris and its application in wastewater treatment in a tropical city—Bangkok, Thailand

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