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US-12618078-B2 - Chlorophyte algae having improved productivity

US12618078B2US 12618078 B2US12618078 B2US 12618078B2US-12618078-B2

Abstract

The invention involves mutant or recombinant Chlorophyte algal organisms that have a genetic modification in a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43). In one embodiment the Chlorophyte organisms are Trebouxiophyte algae that are diploid or polyploid for a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43). The mutant organisms can have a genetic modification in one allele of the gene but not in another allele of the gene. The mutant or algal organisms have higher biomass and lipid productivity. Additional mutant or algal organisms are disclosed that also have a genetic modification to one or more genes encoding a light harvesting chlorophyll a/b (binding) protein.

Inventors

  • Fedor Kuzminov
  • Mahva NAGHIPOR
  • Moena Aqui
  • Yingjun Wang
  • John H. Verruto

Assignees

  • PHYKION INC.

Dates

Publication Date
20260505
Application Date
20220422

Claims (20)

  1. 1 . A mutant Trebouxiophyte algal organism comprising: a disruption in a first allele of a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43) protein having at least 90% sequence identity to either SEQ ID NO: 2 or 4, and comprising a second, active allele of the gene encoding a chloroplastic signal recognition particle 43 (cpSRP43) protein having at least 90% sequence identity to the other of SEQ ID NO: 2 or 4, that does not comprise a disruption, and wherein the first allele and the second allele are not the same allele.
  2. 2 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has at least 5% greater biomass productivity than a corresponding control organism not having the disruption of the first allele of the gene encoding a chloroplastic SRP43 protein.
  3. 3 . The mutant Trebouxiophyte algal organism of claim 2 wherein the first allele of the gene encodes a cpSRP43 protein having at least 90% sequence identity to SEQ ID NO: 2 and the second allele encodes a cpSRP43 protein having at least 90% sequence identity to SEQ ID NO: 4.
  4. 4 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism is of the genus Picochlorum.
  5. 5 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a PSII σ450 value of less than 300 A 2 , and a PSII σ520 value of less than 100 A 2 .
  6. 6 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a PSI σ450 value of less than 500 A 2 , and a PSI σ520 value of less than 150 A 2 .
  7. 7 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a biomass productivity at least 7% higher than a corresponding control organism.
  8. 8 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a ratio of PSI/PSII antenna cross section of less than 1.5.
  9. 9 . The mutant Trebouxiophyte algal organism of claim 1 wherein the organism has a Chl a:b ratio of greater than 6.0.
  10. 10 . The mutant Trebouxiophyte algal organism of claim 2 wherein the organism has: a PSII σ450 value of less than 300 A 2 and a PSII σ520 value of less than 100 A 2 , or a PSI σ450 value of less than 500 A 2 , and a PSI σ520 value of less than 150 A 2 , or a PSI/PSII value of less than 0.65 and a Chl a:b ratio of greater than 6.0.
  11. 11 . The mutant Trebouxiophyte algal organism of claim 3 wherein the organism is diploid.
  12. 12 . The mutant Trebouxiophyte algal organism of claim 3 wherein the organism is polyploid.
  13. 13 . The mutant Trebouxiophyte algal organism of claim 2 further comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein of PSI comprising at least 90% sequence identity to any one of SEQ ID NOs: 7-12.
  14. 14 . The mutant Trebouxiophyte algal organism of claim 1 comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein LHCP-11 of PSI, and/or a gene encoding a light harvesting complex LHCP-21 of PSI.
  15. 15 . The mutant Trebouxiophyte algal organism of claim 1 comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein of PSI having a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 21, or a disruption of a gene encoding a light harvesting complex of PSI having a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 22.
  16. 16 . The mutant Trebouxiophyte algal organism of claim 2 comprising a disruption of a gene encoding a light harvesting chlorophyll a/b binding protein of PSI having a sequence with at least 90% sequence identity to SEQ ID NO: 7, and a disruption of a gene encoding a light harvesting complex of PSI having a sequence with at least 90% sequence identity to SEQ ID NO: 8.
  17. 17 . The mutant Trebouxiophyte algal organism of claim 16 having a lipid productivity at least 4% higher than a corresponding control algal organism.
  18. 18 . The mutant Trebouxiophyte algal organism of claim 16 wherein the mutant Trebouxiophyte algal organism is a member of the genus Pichochlorum.
  19. 19 . A biomass comprising the mutant Trebouxiophyte algal organism of claim 1 .
  20. 20 . A biomass comprising the mutant Trebouxiophyte algal organism of claim 11 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims benefit of priority under 35 U.S.C. § 119(e) of U.S. Ser. No. 63/179,044, filed Apr. 23, 2021, the entire contents of which is incorporated herein by reference in its entirety. INCORPORATION OF SEQUENCE LISTING The material in the accompanying sequence listing is hereby incorporated by reference into this application. The accompanying sequence listing text file name, SGI2300-1_SL.txt, was created May 3, 2022, and is 41.9 kb. The file can be accessed using Microsoft Word on a computer that uses Windows OS. FIELD OF THE INVENTION The invention concerns Chlorophyte algae having a genetic modification to a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43), and optionally a genetic modification to a gene encoding a light harvesting chlorophyll a/b (binding) protein (LHCP) and having higher biomass and/or lipid productivity. BACKGROUND OF THE INVENTION Algae represent a potentially enormous resource for producing an inexpensive source of energy while limiting CO2 emissions. Green algae utilize photosynthesis to harvest light energy from the sun and convert it into biomass derived from carbon dioxide and water. One limitation that limits biomass production in algae is the thermodynamic efficiency of photosynthesis in full sunlight. It is reported that up to 75% of the energy captured from the sun is wasted as heat or fluorescence. Various methods have been applied to increase metabolic or thermodynamic efficiency and therefore increase the biomass production of algae, namely by applying methods of light dilution, rapid mixing, or improvement in the design of photobioreactors. Other methods have involved genetic approaches to increasing efficiency by engineering algal strains with reduced chlorophyll or with a reduced cross-section of the light harvesting antenna complex. When genetic approaches are taken the use of polyploid organisms presents special challenges because such organisms can have multiple copies of relevant genes, and examples of polyploidy can be found in most major groups of algae. Therefore, the scope of algae of interest can be expanded with better genetic approaches for working with these organisms. There is therefore a continuing need for increases in photosynthetic efficiency in useful algae, including polyploid algae, in order to achieve more economically viable uses of algal products. SUMMARY OF THE INVENTION The invention involves mutant photosynthetic algal cells or organisms that have a genetic modification in a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43). In one embodiment the organisms are Chlorophyte algae that are diploid or polyploid for a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43). The mutant organisms can have a genetic modification in one allele of the gene but not in another allele of the gene. The result is a photosynthetic algal organism with higher biomass and lipid productivity. The mutant algal organisms also optionally contain a genetic modification to one or more genes encoding a light harvesting chlorophyll a/b (binding) protein (LHCP). In a first aspect the invention provides a mutant or recombinant Chlorophyte algal organism having a deletion, disruption, or inactivation in a first allele of a gene encoding a chloroplastic signal recognition particle 43 (cpSRP43) protein, and further having a second, active allele of the gene encoding a chloroplastic signal recognition particle 43 (cpSRP43) protein that does not comprise a deletion, disruption, or inactivation. The mutant algal organism can have at least 5% greater biomass productivity than a corresponding control organism not having the deletion, disruption, or inactivation of the first allele of the gene encoding a chloroplastic SRP43 protein. The mutant algal organism of the invention can be diploid or polyploid. In various embodiments the mutant or recombinant Chlorophyte organism is a Trebouxiophyte algal organism, which can be of the genus Picochlorum. In some embodiments the mutant algal organism can have a PSII σ450 value of less than 300 A2, and a PSII σ520 value of less than 100 A2. In some embodiments the mutant algal organism can have a PSI σ450 value of less than 500 A2, and a PSI σ520 value of less than 150 A2. In various embodiments the mutant algal organism can have a biomass productivity at least 7% higher than a corresponding control organism. The mutant algal organism can have a ratio of PSI/PSII antenna cross section of less than 1.5. The mutant algal organism can have a Chl a:b ratio of greater than 6.0. In one embodiment the mutant algal organism has 1) a PSII σ450 value of less than 300 A2, and a PSII σ520 value of less than 100 A2; 2) a PSI σ450 value of less than 500 A2, and a PSI σ520 value of less than 150 A2; 3) a PSI/PSII value of less than 0.65; and 4) a Chl a:b ratio of greater than 6.0. The mutant algal organism can have a first allele having a sequen