skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Enhancing oil production and harvest by combining the marine alga Nannochloropsis oceanica and the oleaginous fungus Mortierella elongata

Abstract

Background: Although microalgal biofuels have potential advantages over conventional fossil fuels, high production costs limit their application in the market. We developed bio-flocculation and incubation methods for the marine alga, Nannochloropsis oceanica CCMP1779, and the oleaginous fungus, Mortierella elongata AG77, resulting in increased oil productivity. Results: By growing separately and then combining the cells, the M. elongata mycelium could efficiently capture N. oceanica due to an intricate cellular interaction between the two species leading to bio-flocculation. Use of a high-salt culture medium induced accumulation of triacylglycerol (TAG) and enhanced the contents of polyunsaturated fatty acids (PUFAs) including arachidonic acid and docosahexaenoic acid in M. elongata. To increase TAG productivity in the alga, we developed an effective, reduced nitrogen-supply regime based on ammonium in environmental photobioreactors. Under optimized conditions, N. oceanica produced high levels of TAG that could be indirectly monitored by following chlorophyll content. Combining N. oceanica and M. elongata to initiate bio-flocculation yielded high levels of TAG and total fatty acids, with ~ 15 and 22% of total dry weight (DW), respectively, as well as high levels of PUFAs. Genetic engineering of N. oceanica for higher TAG content in nutrient-replete medium was accomplished by overexpressing DGTT5, a gene encodingmore » the type II acyl-CoA:diacylglycerol acyltransferase 5. Combined with bio-flocculation, this approach led to increased production of TAG under nutrient-replete conditions (~ 10% of DW) compared to the wild type (~ 6% of DW). In conclusion, the combined use of M. elongata and N. oceanica with available genomes and genetic engineering tools for both species opens up new avenues to improve biofuel productivity and allows for the engineering of polyunsaturated fatty acids.« less

Authors:
 [1];  [2];  [3];  [4];  [2];  [5];  [6]; ORCiD logo [7]
  1. Michigan State Univ., East Lansing, MI (United States). Dept. of Energy-Plant Research Lab.; Michigan State Univ., East Lansing, MI (United States). Dept. of Biochemistry and Molecular Biology
  2. Michigan State Univ., East Lansing, MI (United States). Dept. of Biochemistry and Molecular Biology
  3. Michigan State Univ., East Lansing, MI (United States). Dept. of Energy-Plant Research Lab.
  4. Michigan State Univ., East Lansing, MI (United States). Dept. of Biochemistry and Molecular Biology; Georg-August-Univ., Goettingen (Germany). Albrecht-von-Haller-Inst. for Plant Sciences, Dept. of Plant Biochemistry
  5. Michigan State Univ., East Lansing, MI (United States). Dept. of Biochemistry and Molecular Biology; Michigan State Univ., East Lansing, MI (United States). Great Lakes Bioenergy Research Center
  6. Michigan State Univ., East Lansing, MI (United States). Dept. of Plant, Soil and Microbial Sciences; Michigan State Univ., East Lansing, MI (United States). Great Lakes Bioenergy Research Center
  7. Michigan State Univ., East Lansing, MI (United States). Dept. of Energy-Plant Research Lab.; Michigan State Univ., East Lansing, MI (United States). Dept. of Biochemistry and Molecular Biology; Michigan State Univ., East Lansing, MI (United States). Great Lakes Bioenergy Research Center; Michigan State Univ., East Lansing, MI (United States). Dept. of Plant Biology
Publication Date:
Research Org.:
Michigan State Univ., East Lansing, MI (United States). Great Lakes Bioenergy Research Center
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division; National Science Foundation (NSF)
OSTI Identifier:
1459413
Grant/Contract Number:  
SC0018409; FC02-07ER64494; FG02-91ER20021; 627266
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Biotechnology for Biofuels
Additional Journal Information:
Journal Volume: 11; Journal Issue: 1; Journal ID: ISSN 1754-6834
Publisher:
BioMed Central
Country of Publication:
United States
Language:
English
Subject:
09 BIOMASS FUELS; Nannochloropsis; Mortierella; Bio‑flocculation; Polyunsaturated fatty acid; Triacylglycerol; Photobioreactor; Microalgae; Filamentous fungi; Cell–wall interaction; Biofuel; Nitrogen starvation

Citation Formats

Du, Zhi-Yan, Alvaro, Jonathan, Hyden, Brennan, Zienkiewicz, Krzysztof, Benning, Nils, Zienkiewicz, Agnieszka, Bonito, Gregory, and Benning, Christoph. Enhancing oil production and harvest by combining the marine alga Nannochloropsis oceanica and the oleaginous fungus Mortierella elongata. United States: N. p., 2018. Web. doi:10.1186/s13068-018-1172-2.
Du, Zhi-Yan, Alvaro, Jonathan, Hyden, Brennan, Zienkiewicz, Krzysztof, Benning, Nils, Zienkiewicz, Agnieszka, Bonito, Gregory, & Benning, Christoph. Enhancing oil production and harvest by combining the marine alga Nannochloropsis oceanica and the oleaginous fungus Mortierella elongata. United States. doi:10.1186/s13068-018-1172-2.
Du, Zhi-Yan, Alvaro, Jonathan, Hyden, Brennan, Zienkiewicz, Krzysztof, Benning, Nils, Zienkiewicz, Agnieszka, Bonito, Gregory, and Benning, Christoph. Fri . "Enhancing oil production and harvest by combining the marine alga Nannochloropsis oceanica and the oleaginous fungus Mortierella elongata". United States. doi:10.1186/s13068-018-1172-2. https://www.osti.gov/servlets/purl/1459413.
@article{osti_1459413,
title = {Enhancing oil production and harvest by combining the marine alga Nannochloropsis oceanica and the oleaginous fungus Mortierella elongata},
author = {Du, Zhi-Yan and Alvaro, Jonathan and Hyden, Brennan and Zienkiewicz, Krzysztof and Benning, Nils and Zienkiewicz, Agnieszka and Bonito, Gregory and Benning, Christoph},
abstractNote = {Background: Although microalgal biofuels have potential advantages over conventional fossil fuels, high production costs limit their application in the market. We developed bio-flocculation and incubation methods for the marine alga, Nannochloropsis oceanica CCMP1779, and the oleaginous fungus, Mortierella elongata AG77, resulting in increased oil productivity. Results: By growing separately and then combining the cells, the M. elongata mycelium could efficiently capture N. oceanica due to an intricate cellular interaction between the two species leading to bio-flocculation. Use of a high-salt culture medium induced accumulation of triacylglycerol (TAG) and enhanced the contents of polyunsaturated fatty acids (PUFAs) including arachidonic acid and docosahexaenoic acid in M. elongata. To increase TAG productivity in the alga, we developed an effective, reduced nitrogen-supply regime based on ammonium in environmental photobioreactors. Under optimized conditions, N. oceanica produced high levels of TAG that could be indirectly monitored by following chlorophyll content. Combining N. oceanica and M. elongata to initiate bio-flocculation yielded high levels of TAG and total fatty acids, with ~ 15 and 22% of total dry weight (DW), respectively, as well as high levels of PUFAs. Genetic engineering of N. oceanica for higher TAG content in nutrient-replete medium was accomplished by overexpressing DGTT5, a gene encoding the type II acyl-CoA:diacylglycerol acyltransferase 5. Combined with bio-flocculation, this approach led to increased production of TAG under nutrient-replete conditions (~ 10% of DW) compared to the wild type (~ 6% of DW). In conclusion, the combined use of M. elongata and N. oceanica with available genomes and genetic engineering tools for both species opens up new avenues to improve biofuel productivity and allows for the engineering of polyunsaturated fatty acids.},
doi = {10.1186/s13068-018-1172-2},
journal = {Biotechnology for Biofuels},
number = 1,
volume = 11,
place = {United States},
year = {Fri Jun 22 00:00:00 EDT 2018},
month = {Fri Jun 22 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share:

Works referenced in this record:

Plant triacylglycerols as feedstocks for the production of biofuels
journal, May 2008