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

Title: Low-phosphate-selected Auxenochlorella protothecoides redirects phosphate to essential pathways while producing more biomass

Abstract

Despite the capacity to accumulate ~70% w/w of lipids, commercially produced unicellular green alga A. protothecoides may become compromised due to the high cost of phosphate fertilizers. To address this limitation A. protothecoides was selected for adaptation to conditions of 100× and 5× lower phosphate and peptone, respectively, compared to ‘wild-type media’. The A. protothecoides showed initial signs of adaptation by 45–50 days, and steady state growth at ~100 days. The low phosphate (P)-adapted strain produced up to ~30% greater biomass, while total lipids (~10% w/w) remained about the same, compared to the wild-type strain. Metabolomic analyses indicated that the low P-adapted produced 3.3-fold more saturated palmitic acid (16:0) and 2.2-fold less linolenic acid (18:3), compared to the wild-type strain, resulting in an ~11% increase in caloric value, from 19.5kJ/g for the wild- type strain to 21.6kJ/g for the low P-adapted strain, due to the amounts and composition of certain saturated fatty acids, compared to the wild type strain. Biochemical changes in A. protothecoides adapted to lower phosphate conditions were assessed by comparative RNA-Seq analysis, which yielded 27,279 transcripts. Among them, 2,667 and 15 genes were significantly down- and up-regulated, at >999-fold and >3-fold (adjusted p-value <0.1),respectively. The expression ofmore » genes encoding proteins involved in cellular processes such as division, growth, and membrane biosynthesis, showed a trend toward down-regulation. At the genomic level, synonymous SNPs and Indels were observed primarily in coding regions, with the 40S ribosomal subunit gene harboring substantial SNPs. Overall, the adapted strain out-performed the wild-type strain by prioritizing the use of its limited phosphate supply for essential biological processes. The low P-adapted A. protothecoides is expected to be more economical to grow over the wild-type strain, based on overall greater productivity and caloric content, while importantly, also requiring 100-fold less phosphate.« less

Authors:
 [1];  [2];  [3];  [4]; ORCiD logo [3]
  1. Colorado State Univ., Fort Collins, CO (United States)
  2. Bellevue Univ., NE (United States)
  3. Univ. of Arizona, Tucson, AZ (United States)
  4. Univ. of Virginia, Charlottesville, VA (United States)
Publication Date:
Research Org.:
Univ. of Arizona, Tucson, AZ (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B)
OSTI Identifier:
1592767
Grant/Contract Number:  
ee0006269
Resource Type:
Accepted Manuscript
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 13; Journal Issue: 6; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES

Citation Formats

Park, Sang-Hyuck, Kyndt, John, Chougule, Kapeel, Park, Jeong-Jin, and Brown, Judith K. Low-phosphate-selected Auxenochlorella protothecoides redirects phosphate to essential pathways while producing more biomass. United States: N. p., 2018. Web. doi:10.1371/journal.pone.0198953.
Park, Sang-Hyuck, Kyndt, John, Chougule, Kapeel, Park, Jeong-Jin, & Brown, Judith K. Low-phosphate-selected Auxenochlorella protothecoides redirects phosphate to essential pathways while producing more biomass. United States. doi:10.1371/journal.pone.0198953.
Park, Sang-Hyuck, Kyndt, John, Chougule, Kapeel, Park, Jeong-Jin, and Brown, Judith K. Tue . "Low-phosphate-selected Auxenochlorella protothecoides redirects phosphate to essential pathways while producing more biomass". United States. doi:10.1371/journal.pone.0198953. https://www.osti.gov/servlets/purl/1592767.
@article{osti_1592767,
title = {Low-phosphate-selected Auxenochlorella protothecoides redirects phosphate to essential pathways while producing more biomass},
author = {Park, Sang-Hyuck and Kyndt, John and Chougule, Kapeel and Park, Jeong-Jin and Brown, Judith K.},
abstractNote = {Despite the capacity to accumulate ~70% w/w of lipids, commercially produced unicellular green alga A. protothecoides may become compromised due to the high cost of phosphate fertilizers. To address this limitation A. protothecoides was selected for adaptation to conditions of 100× and 5× lower phosphate and peptone, respectively, compared to ‘wild-type media’. The A. protothecoides showed initial signs of adaptation by 45–50 days, and steady state growth at ~100 days. The low phosphate (P)-adapted strain produced up to ~30% greater biomass, while total lipids (~10% w/w) remained about the same, compared to the wild-type strain. Metabolomic analyses indicated that the low P-adapted produced 3.3-fold more saturated palmitic acid (16:0) and 2.2-fold less linolenic acid (18:3), compared to the wild-type strain, resulting in an ~11% increase in caloric value, from 19.5kJ/g for the wild- type strain to 21.6kJ/g for the low P-adapted strain, due to the amounts and composition of certain saturated fatty acids, compared to the wild type strain. Biochemical changes in A. protothecoides adapted to lower phosphate conditions were assessed by comparative RNA-Seq analysis, which yielded 27,279 transcripts. Among them, 2,667 and 15 genes were significantly down- and up-regulated, at >999-fold and >3-fold (adjusted p-value <0.1),respectively. The expression of genes encoding proteins involved in cellular processes such as division, growth, and membrane biosynthesis, showed a trend toward down-regulation. At the genomic level, synonymous SNPs and Indels were observed primarily in coding regions, with the 40S ribosomal subunit gene harboring substantial SNPs. Overall, the adapted strain out-performed the wild-type strain by prioritizing the use of its limited phosphate supply for essential biological processes. The low P-adapted A. protothecoides is expected to be more economical to grow over the wild-type strain, based on overall greater productivity and caloric content, while importantly, also requiring 100-fold less phosphate.},
doi = {10.1371/journal.pone.0198953},
journal = {PLoS ONE},
number = 6,
volume = 13,
place = {United States},
year = {2018},
month = {6}
}

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

Save / Share:

Works referenced in this record:

Fitness effects of new mutations in Chlamydomonas reinhardtii across two stress gradients
journal, January 2016

  • Kraemer, S. A.; Morgan, A. D.; Ness, R. W.
  • Journal of Evolutionary Biology, Vol. 29, Issue 3
  • DOI: 10.1111/jeb.12807

Short-term algal toxicity test based on phosphate uptake
journal, April 2004


Dynamics of phosphate limited algal growth: Simulation of phosphate shocks
journal, February 1978


Review of the algal biology program within the National Alliance for Advanced Biofuels and Bioproducts
journal, March 2017


MAKER-P: A Tool Kit for the Rapid Creation, Management, and Quality Control of Plant Genome Annotations
journal, December 2013

  • Campbell, Michael S.; Law, MeiYee; Holt, Carson
  • Plant Physiology, Vol. 164, Issue 2
  • DOI: 10.1104/pp.113.230144

Placing microalgae on the biofuels priority list: a review of the technological challenges
journal, November 2009

  • Greenwell, H. C.; Laurens, L. M. L.; Shields, R. J.
  • Journal of The Royal Society Interface, Vol. 7, Issue 46
  • DOI: 10.1098/rsif.2009.0322

Best practices in heterotrophic high-cell-density microalgal processes: achievements, potential and possible limitations
journal, May 2011

  • Bumbak, Fabian; Cook, Stella; Zachleder, Vilém
  • Applied Microbiology and Biotechnology, Vol. 91, Issue 1
  • DOI: 10.1007/s00253-011-3311-6

Kinetics of phosphate limited algal growth
journal, April 1977


Microalgal triacylglycerols as feedstocks for biofuel production: perspectives and advances
journal, May 2008


Selection and adaptation of microalgae to growth in 100% unfiltered coal-fired flue gas
journal, June 2017


Large-scale biodiesel production from microalgaChlorella protothecoides through heterotrophic cultivation in bioreactors
journal, January 2007

  • Li, Xiufeng; Xu, Han; Wu, Qingyu
  • Biotechnology and Bioengineering, Vol. 98, Issue 4
  • DOI: 10.1002/bit.21489

Genetic Approach for the Fast Discovery of Phenazine Producing Bacteria
journal, May 2011

  • Schneemann, Imke; Wiese, Jutta; Kunz, Anna Lena
  • Marine Drugs, Vol. 9, Issue 5
  • DOI: 10.3390/md9050772

RNA-Seq: a revolutionary tool for transcriptomics
journal, January 2009

  • Wang, Zhong; Gerstein, Mark; Snyder, Michael
  • Nature Reviews Genetics, Vol. 10, Issue 1
  • DOI: 10.1038/nrg2484

Chromosome-level genome assembly and transcriptome of the green alga Chromochloris zofingiensis illuminates astaxanthin production
journal, May 2017

  • Roth, Melissa S.; Cokus, Shawn J.; Gallaher, Sean D.
  • Proceedings of the National Academy of Sciences, Vol. 114, Issue 21
  • DOI: 10.1073/pnas.1619928114

Applications of next-generation sequencing technologies in functional genomics
journal, November 2008


SNP Markers and Their Impact on Plant Breeding
journal, January 2012

  • Mammadov, Jafar; Aggarwal, Rajat; Buyyarapu, Ramesh
  • International Journal of Plant Genomics, Vol. 2012
  • DOI: 10.1155/2012/728398

Lipid accumulation from pinewood pyrolysates by Rhodosporidium diobovatum and Chlorella vulgaris for biodiesel production
journal, August 2016


A chemostat culture as a tool for the improvement of a recombinant E. coli strain over-producing penicillin G acylase : Improvement of a Recombinant
journal, August 2001

  • Marešová, H.; Štěpánek, V.; Kyslík, P.
  • Biotechnology and Bioengineering, Vol. 75, Issue 1
  • DOI: 10.1002/bit.1163

An Outlook on Microalgal Biofuels
journal, August 2010


Algal biomass as a global source of transport fuels: Overview and development perspectives
journal, August 2014

  • Ullah, Kifayat; Ahmad, Mushtaq
  • Progress in Natural Science: Materials International, Vol. 24, Issue 4
  • DOI: 10.1016/j.pnsc.2014.06.008

Continuous cultivation of microorganisms: A review
journal, November 1966