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Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells.

Miranda AF, Taha M, Wrede D, Morrison P, Ball AS, Stevenson T, Mouradov A - Biotechnol Biofuels (2015)

Bottom Line: For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures.The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus.Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

View Article: PubMed Central - PubMed

Affiliation: School of Applied Sciences, Royal Melbourne Institute of Technology University, Bundoora, VIC 3083 Australia.

ABSTRACT

Background: Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive.

Results: This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its genetically modified derivatives that have been altered to enable secretion of free fatty acids into growth media. Secreted free fatty acids are potentially used by fungal cells as a carbon source for growth and ex-novo production of lipids. For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures. The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus.

Conclusion: Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

No MeSH data available.


Microscopic analysis of A. fumigatus-Synechocystis associations. a, bA. fumigatus-SD100 pellets; c, dA. fumigatus-SD100 and A. fumigatus-SD216; e, f SD100 cells attached to A. fumigatus filaments; g, hA. fumigatus/GLU filaments stained with Nile red; iA. fumigatus/TWS filaments stained with Nile red; j FFA droplets secreted into growth media by SD277 growing in mono-culture; k–m FFA droplets attached to A. fumigatus filaments after mixing with SD232 (k) and SD277 (l, m) cultures at t = 0. Red colour is the autofluorescence of cyanobacterial phycobilisomes. Scalesa, b = 1 mm; c–m = 20 µm
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Fig3: Microscopic analysis of A. fumigatus-Synechocystis associations. a, bA. fumigatus-SD100 pellets; c, dA. fumigatus-SD100 and A. fumigatus-SD216; e, f SD100 cells attached to A. fumigatus filaments; g, hA. fumigatus/GLU filaments stained with Nile red; iA. fumigatus/TWS filaments stained with Nile red; j FFA droplets secreted into growth media by SD277 growing in mono-culture; k–m FFA droplets attached to A. fumigatus filaments after mixing with SD232 (k) and SD277 (l, m) cultures at t = 0. Red colour is the autofluorescence of cyanobacterial phycobilisomes. Scalesa, b = 1 mm; c–m = 20 µm

Mentions: Detailed light and environmental scanning electron microscopy of the A. fumigatus-SD pellets showed that cyanobacterial cells not only trapped within fungal filaments but were clearly attached to them (Fig. 3; Additional file 7: Figure S6).Fig. 3


Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells.

Miranda AF, Taha M, Wrede D, Morrison P, Ball AS, Stevenson T, Mouradov A - Biotechnol Biofuels (2015)

Microscopic analysis of A. fumigatus-Synechocystis associations. a, bA. fumigatus-SD100 pellets; c, dA. fumigatus-SD100 and A. fumigatus-SD216; e, f SD100 cells attached to A. fumigatus filaments; g, hA. fumigatus/GLU filaments stained with Nile red; iA. fumigatus/TWS filaments stained with Nile red; j FFA droplets secreted into growth media by SD277 growing in mono-culture; k–m FFA droplets attached to A. fumigatus filaments after mixing with SD232 (k) and SD277 (l, m) cultures at t = 0. Red colour is the autofluorescence of cyanobacterial phycobilisomes. Scalesa, b = 1 mm; c–m = 20 µm
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4635583&req=5

Fig3: Microscopic analysis of A. fumigatus-Synechocystis associations. a, bA. fumigatus-SD100 pellets; c, dA. fumigatus-SD100 and A. fumigatus-SD216; e, f SD100 cells attached to A. fumigatus filaments; g, hA. fumigatus/GLU filaments stained with Nile red; iA. fumigatus/TWS filaments stained with Nile red; j FFA droplets secreted into growth media by SD277 growing in mono-culture; k–m FFA droplets attached to A. fumigatus filaments after mixing with SD232 (k) and SD277 (l, m) cultures at t = 0. Red colour is the autofluorescence of cyanobacterial phycobilisomes. Scalesa, b = 1 mm; c–m = 20 µm
Mentions: Detailed light and environmental scanning electron microscopy of the A. fumigatus-SD pellets showed that cyanobacterial cells not only trapped within fungal filaments but were clearly attached to them (Fig. 3; Additional file 7: Figure S6).Fig. 3

Bottom Line: For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures.The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus.Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

View Article: PubMed Central - PubMed

Affiliation: School of Applied Sciences, Royal Melbourne Institute of Technology University, Bundoora, VIC 3083 Australia.

ABSTRACT

Background: Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive.

Results: This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its genetically modified derivatives that have been altered to enable secretion of free fatty acids into growth media. Secreted free fatty acids are potentially used by fungal cells as a carbon source for growth and ex-novo production of lipids. For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures. The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus.

Conclusion: Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

No MeSH data available.