Effects of phosphorous deficiency of a microalga Nannochloropsis oculata on its fatty acid profiles and intracellular structure and the effectiveness in rotifer nutrition

Matsui, Hideaki; Shiozaki, Kazuhiro; Okumura, Yutaka; Ishikawa, Manabu; Waqalevu, Viliame; Hayasaka, Oki; Honda, Akinobu; Kotani, Tomonari

doi:10.1016/j.algal.2020.101905

Cited by 18 publications

(9 citation statements)

References 75 publications

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“…(McCarthy et al 2022 ) and Adineta editae (Brown et al 2023 ). Additionally, low calcium has been found to be beneficial to the reproductive output of the monogonont rotifer Mytilina brevispina (Sincock 1976 ), and phosphorus deficiency in an algae food source was found to have no impact on population growth of the rotifer of Brachionus plicatilis (Matsui et al 2020 ). The concentration of dissolved ions (herein measured by electrical conductivity) between dilutions of elutriate was likewise unlikely to have substantially contributed to observed differences in population growth.…”

Section: Discussionmentioning

confidence: 99%

Population growth of two limno-terrestrial Antarctic microinvertebrates in different aqueous soil media

McCarthy,

Brown,

King

et al. 2024

Environ Sci Pollut Res

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Terrestrial microinvertebrates provide important carbon and nutrient cycling roles in soil environments, particularly in Antarctica where larger macroinvertebrates are absent. The environmental preferences and ecology of rotifers and tardigrades in terrestrial environments, including in Antarctica, are not as well understood as their temperate aquatic counterparts. Developing laboratory cultures is critical to provide adequate numbers of individuals for controlled laboratory experimentation. In this study, we explore aspects of optimising laboratory culturing for two terrestrially sourced Antarctic microinvertebrates, a rotifer (Habrotrocha sp.) and a tardigrade (Acutuncus antarcticus). We tested a soil elutriate and a balanced salt solution (BSS) to determine their suitability as culturing media. Substantial population growth of rotifers and tardigrades was observed in both media, with mean rotifer population size increasing from 5 to 448 ± 95 (soil elutriate) and 274 ± 78 (BSS) individuals over 60 days and mean tardigrade population size increasing from 5 to 187 ± 65 (soil elutriate) and 138 ± 37 (BSS) over 160 days. We also tested for optimal dilution of soil elutriate in rotifer cultures, with 20–80% dilutions producing the largest population growth with the least variation in the 40% dilution after 36 days. Culturing methods developed in this study are recommended for use with Antarctica microinvertebrates and may be suitable for similar limno-terrestrial microinvertebrates from other regions.

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Section: Discussionmentioning

confidence: 99%

Population growth of two limno-terrestrial Antarctic microinvertebrates in different aqueous soil media

McCarthy,

Brown,

King

et al. 2024

Environ Sci Pollut Res

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“…In Nannochloropsis C16:0, C16:1, and C18:1 are the main components of TAGs [ 49 , 50 ], where they accumulate under stress, especially under nitrogen starvation, via de novo synthesis through the acyl-CoA-dependent pathway, or via conversion of membranes [ 51 ]. On the other hand, C18:2 and C20:5, n-3 are mainly present in polar lipids [ 50 ], and they are accumulated under conditions requiring membrane plasticity, such as low temperatures, while they are negatively affected by nutrient limitation. However, PUFAs might also be synthesized de novo during nutrient starvation and transferred to TAGs [ 51 , 52 , 53 ].…”

Section: Discussionmentioning

confidence: 99%

“…The treatment of missing biomass concentration for the rest of the cases is explained in the Supplementary Materials (S4) [ 50 , 68 , 69 ].…”

Section: Methodsmentioning

confidence: 99%

“…Data on phosphate availability was more sparse, with less authors providing information on the temporal profile or the final values of phosphate concentration [ 1 , 2 , 45 , 50 , 65 ]. The lower limit for imputation was estimated assuming biomass phosphorus content 2.5% and using the upper biomass concentration limit, while the upper limit was estimated assuming 0.5% biomass phosphorus content and using the lower biomas concentration limit.…”

Section: Methodsmentioning

confidence: 99%

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LASSO Regression with Multiple Imputations for the Selection of Key Variables Affecting the Fatty Acid Profile of Nannochloropsis oculata

Andriopoulos,

Kornaros

2023

Marine Drugs

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The marine microalga Nannochloropsis oculata has garnered significant interest as a potential source of lipids, both for biofuel and nutrition, containing significant amounts of C16:0, C16:1, and C20:5, n-3 (EPA) fatty acids (FA). Growth parameters such as temperature, pH, light intensity, and nutrient availability play a crucial role in the fatty acid profile of microalgae, with N. oculata being no exception. This study aims to identify key variables for the FA profile of N. oculata grown autotrophically. To that end, the most relevant literature data were gathered and combined with our previous work as well as with novel experimental data, with 121 observations in total. The examined variables were the percentages of C14:0, C16:0, C16:1, C18:1, C18:2, and C20:5, n-3 in total FAs, their respective ratios to C16:0, and the respective content of biomass in those fatty acids in terms of ash free dry weight. Many potential predictor variables were collected, while dummy variables were introduced to account for bias in the measured variables originating from different authors as well as for other parameters. The method of multiple imputations was chosen to handle missing data, with limits based on the literature and model-based estimation, such as using the software PHREEQC and residual modelling for the estimation of pH. To eliminate unimportant predictor variables, LASSO (Least Absolute Shrinkage and Selection Operator) regression analysis with a novel definition of optimal lambda was employed. LASSO regression identified the most relevant predictors while minimizing the risk of overfitting the model. Subsequently, stepwise linear regression with interaction terms was used to further study the effects of the selected predictors. After two rounds of regression, sparse refined models were acquired, and their coefficients were evaluated based on significance. Our analysis confirms well-known effects, such as that of temperature, and it uncovers novel unreported effects of aeration, calcium, magnesium, and manganese. Of special interest is the negative effect of aeration on polyunsaturated fatty acids (PUFAs), which is possibly related to the enzymatic kinetics of fatty acid desaturation under increased oxygen concentration. These findings contribute to the optimization of the fatty acid profile of N. oculata for different purposes, such as production of, high in PUFAs, food or feed, or production of, high in saturated and monounsaturated FA methyl esters (FAME), biofuels.

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“…The freeze-dried cells (15 mg) were mixed with 500 µL of 0.1 M NaOH in a Sarstedt 2.0 mL screwcap tube and heated at 80 • C for 1 h to lyse microalgal cells and extract protein, according to the method developed by Matsui et al [29]. The resultant cell lysate was then centrifuged at 16,000× g for 20 min at 4 • C, and the supernatant was pooled into a 15 mL Maruemu glass vial.…”

Section: Protein and Amino Acids Analysismentioning

confidence: 99%

Biogas Upgrading by Wild Alkaliphilic Microalgae and the Application Potential of Their Biomass in the Carbon Capture and Utilization Technology

Kikuchi,

Kanai,

Sugiyama

et al. 2024

Fermentation

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Although biogas is a renewable energy source alternative to natural gas, it contains approximately 40 vol% CO2 and, hence, a low calorific value. The sequestration of CO2 from biogas is, therefore, essential before its widespread use. As CO2 can be easily solubilized as carbonate and bicarbonate in alkaline water, in this study, we isolated and characterized alkaliphilic wild microalgae that grow under high-level CO2 conditions and evaluated their application potential in CO2-removal from biogas. For this purpose, freshwater samples were enriched with 10 vol% CO2 and an alkaline culture medium (pH 9.0), wherein almost free CO2 was converted to carbonate and bicarbonate to yield alkaliphilic and high-level CO2-tolerant microalgae. Ten microalgal strains of Micractinium, Chlorella, Scenedesmus/Tetradesmus, or Desmodesmus spp. were isolated, some of which demonstrated good growth even under conditions of >pH 10 and >30 vol% CO2. All algal strains grew well through fixing biogas-derived CO2 in a vial-scale biogas upgrading experiment, which reduced the CO2 level in biogas to an undetectable level. These strains yielded antioxidant carotenoids, including lutein, astaxanthin, zeaxanthin, and β-carotene, particularly rich in lutein (up to 7.3 mg/g dry cells). In addition, these strains contained essential amino acids, accounting for 42.9 mol% of the total amino acids on average, and they were rich in unsaturated fatty acids (comprising 62.2 wt% of total fatty acids). The present study identified strains that can contribute to biogas upgrading technology, and the present findings suggest that their biomass can serve as useful raw material across the food, nutraceutical, and feed industries.

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Effects of phosphorous deficiency of a microalga Nannochloropsis oculata on its fatty acid profiles and intracellular structure and the effectiveness in rotifer nutrition

Cited by 18 publications

References 75 publications

Population growth of two limno-terrestrial Antarctic microinvertebrates in different aqueous soil media

Population growth of two limno-terrestrial Antarctic microinvertebrates in different aqueous soil media

LASSO Regression with Multiple Imputations for the Selection of Key Variables Affecting the Fatty Acid Profile of Nannochloropsis oculata

Biogas Upgrading by Wild Alkaliphilic Microalgae and the Application Potential of Their Biomass in the Carbon Capture and Utilization Technology

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