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Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells

BACKGROUND: Current approaches for quantification of major energy-storage forms in microalgae, including starch, protein and lipids, generally require cell cultivation to collect biomass followed by tedious and time-consuming analytical procedures. Thus, label-free, non-destructive and simultaneous...

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Autores principales: He, Yuehui, Zhang, Peng, Huang, Shi, Wang, Tingting, Ji, Yuetong, Xu, Jian
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5693592/
https://www.ncbi.nlm.nih.gov/pubmed/29177009
http://dx.doi.org/10.1186/s13068-017-0967-x
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author He, Yuehui
Zhang, Peng
Huang, Shi
Wang, Tingting
Ji, Yuetong
Xu, Jian
author_facet He, Yuehui
Zhang, Peng
Huang, Shi
Wang, Tingting
Ji, Yuetong
Xu, Jian
author_sort He, Yuehui
collection PubMed
description BACKGROUND: Current approaches for quantification of major energy-storage forms in microalgae, including starch, protein and lipids, generally require cell cultivation to collect biomass followed by tedious and time-consuming analytical procedures. Thus, label-free, non-destructive and simultaneous quantification of such macromolecules at single-cell resolution is highly desirable in microalgal feedstock development and bioprocess control. RESULTS: Here, we established a method based on single-cell Raman spectra (SCRS) that simultaneously quantifies the contents of starch, protein, triacylglycerol (TAG) and lipid unsaturation degree in individual Chlamydomonas reinhardtii cells. Measurement accuracy for the contents based on full SCRS spectrum each reached 96.86–99.24%, all significantly higher than single peak-based models. However, accuracy and reliability of measurement are dependent on the number of cells sampled, thus a formal mathematical framework was proposed and validated to rationally define “minimal sampling depth” for a given state of cellular population. Furthermore, a barcode consisting of 13 marker Raman peaks was proposed to characterize the temporal dynamics of these energy-storage products, which revealed that the average contents of starch and TAG increased, while their heterogeneity indices decreased, with those of protein being exactly the opposite. Finally, our method is widely applicable, as measurements among cells from liquid suspension culture, wet paste and frozen dried powder all exhibited excellent consistency. CONCLUSIONS: When sampled at proper depth, SCRS can serve as a quantitative and generally applicable tool for characterization and screening of strains and bioprocesses based on the profile of energy-storage macromolecules and their among-cell heterogeneity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-017-0967-x) contains supplementary material, which is available to authorized users.
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spelling pubmed-56935922017-11-24 Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells He, Yuehui Zhang, Peng Huang, Shi Wang, Tingting Ji, Yuetong Xu, Jian Biotechnol Biofuels Methodology BACKGROUND: Current approaches for quantification of major energy-storage forms in microalgae, including starch, protein and lipids, generally require cell cultivation to collect biomass followed by tedious and time-consuming analytical procedures. Thus, label-free, non-destructive and simultaneous quantification of such macromolecules at single-cell resolution is highly desirable in microalgal feedstock development and bioprocess control. RESULTS: Here, we established a method based on single-cell Raman spectra (SCRS) that simultaneously quantifies the contents of starch, protein, triacylglycerol (TAG) and lipid unsaturation degree in individual Chlamydomonas reinhardtii cells. Measurement accuracy for the contents based on full SCRS spectrum each reached 96.86–99.24%, all significantly higher than single peak-based models. However, accuracy and reliability of measurement are dependent on the number of cells sampled, thus a formal mathematical framework was proposed and validated to rationally define “minimal sampling depth” for a given state of cellular population. Furthermore, a barcode consisting of 13 marker Raman peaks was proposed to characterize the temporal dynamics of these energy-storage products, which revealed that the average contents of starch and TAG increased, while their heterogeneity indices decreased, with those of protein being exactly the opposite. Finally, our method is widely applicable, as measurements among cells from liquid suspension culture, wet paste and frozen dried powder all exhibited excellent consistency. CONCLUSIONS: When sampled at proper depth, SCRS can serve as a quantitative and generally applicable tool for characterization and screening of strains and bioprocesses based on the profile of energy-storage macromolecules and their among-cell heterogeneity. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13068-017-0967-x) contains supplementary material, which is available to authorized users. BioMed Central 2017-11-17 /pmc/articles/PMC5693592/ /pubmed/29177009 http://dx.doi.org/10.1186/s13068-017-0967-x Text en © The Author(s) 2017 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 Methodology
He, Yuehui
Zhang, Peng
Huang, Shi
Wang, Tingting
Ji, Yuetong
Xu, Jian
Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
title Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
title_full Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
title_fullStr Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
title_full_unstemmed Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
title_short Label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
title_sort label-free, simultaneous quantification of starch, protein and triacylglycerol in single microalgal cells
topic Methodology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5693592/
https://www.ncbi.nlm.nih.gov/pubmed/29177009
http://dx.doi.org/10.1186/s13068-017-0967-x
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