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Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology
BACKGROUND: Three steps are very important in order to produce microalgal lipids: (1) controlling microalgae cultivation via experimental and modeling investigations, (2) optimizing culture conditions to maximize lipids production and to determine the fatty acid profile the most appropriate for biod...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5904985/ https://www.ncbi.nlm.nih.gov/pubmed/29665818 http://dx.doi.org/10.1186/s12944-018-0702-z |
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author | Hadrich, Bilel Akremi, Ismahen Dammak, Mouna Barkallah, Mohamed Fendri, Imen Abdelkafi, Slim |
author_facet | Hadrich, Bilel Akremi, Ismahen Dammak, Mouna Barkallah, Mohamed Fendri, Imen Abdelkafi, Slim |
author_sort | Hadrich, Bilel |
collection | PubMed |
description | BACKGROUND: Three steps are very important in order to produce microalgal lipids: (1) controlling microalgae cultivation via experimental and modeling investigations, (2) optimizing culture conditions to maximize lipids production and to determine the fatty acid profile the most appropriate for biodiesel synthesis, and (3) optimizing the extraction of the lipids accumulated in the microalgal cells. METHODS: Firstly, three kinetics models, namely logistic, logistic-with-lag and modified Gompertz, were tested to fit the experimental kinetics of the Chlorella sp. microalga culture established on standard conditions. Secondly, the response-surface methodology was used for two optimizations in this study. The first optimization was established for lipids production from Chlorella sp. culture under different culture conditions. In fact, different levels of nitrate concentrations, salinities and light intensities were applied to the culture medium in order to study their influences on lipids production and determine their fatty acid profile. The second optimization was concerned with the lipids extraction factors: ultrasonic’s time and temperature, and chloroform-methanol solvent ratio. RESULTS: All models (logistic, logistic-with-lag and modified Gompertz) applied for the experimental kinetics of Chlorella sp. show a very interesting fitting quality. The logistic model was chosen to describe the Chlorella sp. kinetics, since it yielded the most important statistical criteria: coefficient of determination of the order of 94.36%; adjusted coefficient of determination equal to 93.79% and root mean square error reaching 3.685 cells · ml(− 1). Nitrate concentration and the two interactions involving the light intensity (Nitrate concentration × light intensity, and salinities × light intensity) showed a very significant influence on lipids production in the first optimization (p < 0.05). Yet, only the quadratic term of chloroform-methanol solvent ratio showed a significant influence on lipids extraction relative to the second step of optimization (p < 0.05). The two most abundant fatty acid methyl esters (≈72%) derived from the Chlorella sp. microalga cultured in the determined optimal conditions are: palmitic acid (C16:0) and oleic acid (C18:1) with the corresponding yields of 51.69% and 20.55% of total fatty acids, respectively. CONCLUSIONS: Only the nitrate deficiency and the high intensity of light can influence the microalgal lipids production. The corresponding fatty acid methyl esters composition is very suitable for biodiesel production. Lipids extraction is efficient only over long periods of time when using a solvent with a 2/1 chloroform/methanol ratio. |
format | Online Article Text |
id | pubmed-5904985 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-59049852018-04-24 Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology Hadrich, Bilel Akremi, Ismahen Dammak, Mouna Barkallah, Mohamed Fendri, Imen Abdelkafi, Slim Lipids Health Dis Research BACKGROUND: Three steps are very important in order to produce microalgal lipids: (1) controlling microalgae cultivation via experimental and modeling investigations, (2) optimizing culture conditions to maximize lipids production and to determine the fatty acid profile the most appropriate for biodiesel synthesis, and (3) optimizing the extraction of the lipids accumulated in the microalgal cells. METHODS: Firstly, three kinetics models, namely logistic, logistic-with-lag and modified Gompertz, were tested to fit the experimental kinetics of the Chlorella sp. microalga culture established on standard conditions. Secondly, the response-surface methodology was used for two optimizations in this study. The first optimization was established for lipids production from Chlorella sp. culture under different culture conditions. In fact, different levels of nitrate concentrations, salinities and light intensities were applied to the culture medium in order to study their influences on lipids production and determine their fatty acid profile. The second optimization was concerned with the lipids extraction factors: ultrasonic’s time and temperature, and chloroform-methanol solvent ratio. RESULTS: All models (logistic, logistic-with-lag and modified Gompertz) applied for the experimental kinetics of Chlorella sp. show a very interesting fitting quality. The logistic model was chosen to describe the Chlorella sp. kinetics, since it yielded the most important statistical criteria: coefficient of determination of the order of 94.36%; adjusted coefficient of determination equal to 93.79% and root mean square error reaching 3.685 cells · ml(− 1). Nitrate concentration and the two interactions involving the light intensity (Nitrate concentration × light intensity, and salinities × light intensity) showed a very significant influence on lipids production in the first optimization (p < 0.05). Yet, only the quadratic term of chloroform-methanol solvent ratio showed a significant influence on lipids extraction relative to the second step of optimization (p < 0.05). The two most abundant fatty acid methyl esters (≈72%) derived from the Chlorella sp. microalga cultured in the determined optimal conditions are: palmitic acid (C16:0) and oleic acid (C18:1) with the corresponding yields of 51.69% and 20.55% of total fatty acids, respectively. CONCLUSIONS: Only the nitrate deficiency and the high intensity of light can influence the microalgal lipids production. The corresponding fatty acid methyl esters composition is very suitable for biodiesel production. Lipids extraction is efficient only over long periods of time when using a solvent with a 2/1 chloroform/methanol ratio. BioMed Central 2018-04-17 /pmc/articles/PMC5904985/ /pubmed/29665818 http://dx.doi.org/10.1186/s12944-018-0702-z Text en © The Author(s). 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Hadrich, Bilel Akremi, Ismahen Dammak, Mouna Barkallah, Mohamed Fendri, Imen Abdelkafi, Slim Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology |
title | Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology |
title_full | Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology |
title_fullStr | Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology |
title_full_unstemmed | Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology |
title_short | Optimization of lipids’ ultrasonic extraction and production from Chlorella sp. using response-surface methodology |
title_sort | optimization of lipids’ ultrasonic extraction and production from chlorella sp. using response-surface methodology |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5904985/ https://www.ncbi.nlm.nih.gov/pubmed/29665818 http://dx.doi.org/10.1186/s12944-018-0702-z |
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