Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jan 28:12:614612.
doi: 10.3389/fmicb.2021.614612. eCollection 2021.

Volatile Fatty Acids (VFAs) Generated by Anaerobic Digestion Serve as Feedstock for Freshwater and Marine Oleaginous Microorganisms to Produce Biodiesel and Added-Value Compounds

Alok Patel  1 , Amir Mahboubi  2 , Ilona Sárvári Horváth  2 , Mohammad J Taherzadeh  2 , Ulrika Rova  1 , Paul Christakopoulos  1 , Leonidas Matsakas  1
Affiliations

Volatile Fatty Acids (VFAs) Generated by Anaerobic Digestion Serve as Feedstock for Freshwater and Marine Oleaginous Microorganisms to Produce Biodiesel and Added-Value Compounds

Alok Patel et al. Front Microbiol. .

Abstract

Given an increasing focus on environmental sustainability, microbial oils have been suggested as an alternative to petroleum-based products. However, microbial oil production relies on the use of costly sugar-based feedstocks. Substrate limitation, elevated costs, and risk of contamination have sparked the search for alternatives to sugar-based platforms. Volatile fatty acids are generated during anaerobic digestion of organic waste and are considered a promising substrate for microbial oil production. In the present study, two freshwater and one marine microalga along with two thraustochytrids were evaluated for their potential to produce lipids when cultivated on volatile fatty acids generated from food waste via anaerobic digestion using a membrane bioreactor. Freshwater microalgae Auxenochlorella protothecoides and Chlorella sorokiniana synthesized lipids rich in palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), and linoleic acid (C18:2). This composition corresponds to that of soybean and jatropha oils, which are used as biodiesel feedstock. Production of added-value polyunsaturated fatty acids (PUFA) mainly omega-3 fatty acids was examined in three different marine strains: Aurantiochytrium sp. T66, Schizochytrium limacinum SR21, and Crypthecodinium cohnii. Only Aurantiochytrium sp. T66 seemed promising, generating 43.19% docosahexaenoic acid (DHA) and 13.56% docosapentaenoic acid (DPA) in total lipids. In summary, we show that A. protothecoides, C. sorokiniana, and Aurantiochytrium sp. T66 can be used for microbial oil production from food waste material.

Keywords: biofuels; microalgae; oleaginous microorganisms; omega-3 fatty acids; volatile fatty acids.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Batch cultivation of A. protothecoides SAG 211-13 (AP) and C. sorokiniana SAG 211-8k (CS) on a VFAs mixture at (A,B) C/N 20 and (C,D) C/N 60. (A,C) Estimation of cell dry weight (g/L), total lipid concentration (g/L), and lipid content (%, w/w). (B,D) Estimation of residual carbon source in the medium (g/L). Values represent the average ± standard deviation.
FIGURE 2
FIGURE 2
Time course experiment for cell dry weight, lipid concentration, lipid content and residual VFAs when A. protothecoides SAG 211-13 (AP) cultivated on VFAs at C/N 20 (A) and C/N 60 (B) and C. sorokiniana SAG 211-8k (CS) cultivated on VFAS at C/N 20 (C) and C/N 60 (D).
FIGURE 3
FIGURE 3
Biomass and lipid yield of A. protothecoides SAG 211-13 (AP) and C.sorokiniana SAG 211-8k (CS) cultivated on VFAs at C/N 20 (A) and C/N 60 (B).
FIGURE 4
FIGURE 4
Morphologic analysis of cells and lipid droplets of A. protothecoides SAG 211-13 (AP) and C. sorokiniana SAG 211-8k (CS) cultivated on VFAs at C/N 20 and C/N 60. The cells were stained with 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY493/503) and observed by live fluorescence microscopy. Scale bars corresponds to 50 μm.
FIGURE 5
FIGURE 5
Fatty acid profile of A. protothecoides SAG 211-13 (AP) and C. sorokiniana SAG 211-8k (CS) cultivated on a VFAs mixture at (A) C/N 20 and (B) C/N 60. Analysis was carried out by GC-MS. The fatty acids presented as mean value of three independent experiments.
FIGURE 6
FIGURE 6
Batch cultivation of the marine thraustochytrids Aurantiochytrium sp. T66 ATCC-PRA-276 (PRA) and S. limacinum SR21 ATCC-MYA-1381 (SR21), as well as the marine microalga C. cohnii PGM-1 ATCC-30772 (Cohnii) on a VFAs solution at (A,B) C/N 10 and (C,D) C/N 20. (A,C) Estimation of cell dry weight (g/L), total lipid concentration (g/L), and lipid content (%, w/w). (B,D) Estimation of carbon source utilization. Values represent the average ± standard deviation.
FIGURE 7
FIGURE 7
Time course experiment for cell dry weight, lipid concentration, lipid content and residual VFAs when Aurantiochytrium sp. T66 ATCC-PRA-276 (PRA) cultivated on VFAs at C/N 10 (A) and C/N 20 (B); S. limacinum SR21 ATCC-MYA-1381 (SR21), cultivated on VFAS at C/N 10 (C) and C/N 20 (D); and C. cohnii PGM-1 ATCC-30772 (Cohnii) on a VFAs solution at C/N 10 (E) and C/N 20 (F).
FIGURE 8
FIGURE 8
Biomass and lipid yield of Aurantiochytrium sp. T66 ATCC-PRA-276 (PRA) and S. limacinum SR21 ATCC-MYA-1381 and C. cohnii PGM-1 ATCC-30772 (Cohnii) cultivated on VFAs at C/N 10 (A) and C/N 20 (B).
FIGURE 9
FIGURE 9
Morphologic analysis of cells and lipid droplets of Aurantiochytrium sp. T66 ATCC-PRA-276 (PRA), S. limacinum SR21 ATCC-MYA-1381 and C. cohnii PGM-1 ATCC-30772 (Cohnii) cultivated on VFAs at C/N 10 and C/N 20. The cells were stained with 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (BODIPY493/503) and observed by live fluorescence microscopy. Scale bars corresponds to 50 μm.
FIGURE 10
FIGURE 10
Fatty acid profile of the marine thraustochytrids Aurantiochytrium sp. T66 ATCC-PRA-276 (PRA) and S. limacinum SR21 ATCC-MYA-1381 (SR21), as well as the marine microalga C. cohnii PGM-1 ATCC-30772 (Cohnii) cultivated on a VFAs mixture at (A) C/N 10 and (B) C/N 20. Analysis was carried out by GC-MS. The fatty acids presented as mean value of three independent experiments.
See this image and copyright information in PMC

References

    1. Akaraonye E., Keshavarz T., Roy I. (2010). Production of polyhydroxyalkanoates: the future green materials of choice. J. Chem. Technol. Biotechnol. 85 732–743. 10.1002/jctb.2392 - DOI
    1. Anukam A., Mohammadi A., Naqvi M., Granström K. (2019). A review of the chemistry of anaerobic digestion: methods of accelerating and optimizing process efficiency. Processes 7:504 10.3390/pr7080504 - DOI
    1. Ariunbaatar J., Esposito G., Yeh D. H., Lens P. N. L. (2016). Enhanced anaerobic digestion of food waste by supplementing trace elements: role of selenium (vi) and iron (ii). Front. Environ. Sci. 4:8 10.3389/fenvs.2016.00008 - DOI
    1. Awasthi S. K., Sarsaiya S., Awasthi M. K., Liu T., Zhao J., Kumar S., et al. (2020). Changes in global trends in food waste composting: research challenges and opportunities. Bioresour. Technol. 299:122555. 10.1016/j.biortech.2019.122555 - DOI - PubMed
    1. Bannenberg G., Mallon C., Edwards H., Yeadon D., Yan K., Johnson H., et al. (2017). Omega-3 long-chain polyunsaturated fatty acid content and oxidation state of fish oil supplements in New Zealand. Sci. Rep. 7 1–13. 10.1038/s41598-017-01470-4 - DOI - PMC - PubMed

LinkOut - more resources