Recombinant algae having high lipid productivity
The invention provides recombinant algal organisms that have a genetic modification to a gene or nucleic acid sequence encoding an RNA binding domain. In some embodiments the genetic modification can be a functional deletion or attenuation of the gene. The genetic modification results in a mutant organism with increased lipid productivity and/or higher biomass productivity. The lipid products of these mutants can be utilized as biofuels or to manufacture other specialty products. The recombinant mutants can also, optionally, have a genetic modification to a gene encoding an SGI1 polypeptide. Methods of making and using the recombinant algal mutants and methods of producing lipids are also disclosed.
1. A recombinant algal organism comprising a genetic modification in a gene encoding
a) an RNA binding domain and comprising a nucleotide sequence having at least 90% sequence identity to SEQ ID NO: 1 or SEQ ID NO: 2, or
b) an RNA binding domain comprising a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 3 or SEQ ID NO: 4, and
wherein the recombinant algal organism exhibits higher lipid productivity versus a corresponding control algal organism not having the genetic modification.
2. The recombinant algal organism of claim 1 , wherein the organism is a Chlorophyte alga.
3. The recombinant algal organism of claim 2 , wherein the organism is of the Class Trebouxiophyceae.
4. The recombinant algal of claim 1 , wherein the gene encodes an RNA binding domain comprising a sequence with at least 90% sequence identity to SEQ ID NO: 2, or the gene encodes an RNA binding domain having a polypeptide sequence with at least 90% sequence identity to SEQ ID NO: 3.
5. The recombinant algal organism of claim 3 , wherein the genetic modification is a disruption.
6. The recombinant algal organism of claim 3 , wherein the genetic modification results in an attenuation in expression of the encoded RNA binding domain.
7. The recombinant algal organism of claim 6 , wherein the genetic modification is to a regulatory sequence of the gene encoding the RNA binding domain.
8. The recombinant algal organism of claim 7 , wherein the regulatory sequence is a promoter.
9. The recombinant algal organism of claim 8 , wherein the genetic modification comprises a disruption of the promoter.
10. The recombinant algal organism of claim 3 , wherein the genetic modification results in the deletion of at least one amino acid in the encoded RNA binding domain sequence.
11. The recombinant alga of claim 3 , wherein the genetic modification of the nucleic acid sequence encoding the RNA binding domain comprises insertion of a stop codon in the nucleic acid sequence encoding the RNA binding domain.
12. The recombinant alga of claim 1 , wherein the genetic modification is a deletion, a disruption, or an inactivation in the nucleic acid sequence encoding the RNA binding domain.
13. The recombinant alga of claim 1 , wherein the recombinant alga has at least 30% higher lipid productivity versus a control algae.
14. The recombinant alga of claim 13 , wherein the recombinant alga has at least 50% higher lipid productivity versus a control algae.
15. The recombinant alga of claim 1 , wherein the recombinant alga exhibits at least 12 grams per square meter per day of lipid production.
16. The recombinant alga of claim 1 , wherein the recombinant alga further has higher biomass productivity per unit time versus the corresponding control algal cell or organism.
17. The recombinant alga of claim 16 , wherein the recombinant alga has higher biomass productivity under nitrogen deficient conditions.
18. The recombinant alga of claim 1 , wherein the recombinant alga has higher total organic carbon production under nitrogen deficient conditions.
19. The recombinant alga of claim 3 , wherein the recombinant alga is of a family selected from the group consisting of: Oocystaceae, Chlorellaceae, and Eustigmatophyceae.
20. The recombinant alga of claim 3 , wherein the recombinant alga is of a genus selected from the group consisting of: Chlorella, Parachlorella, Picochlorum, Tetraselmis , and Oocystis.
21. The recombinant algal organism of claim 3 , further comprising a genetic modification to a gene encoding an SGI1 polypeptide.
22. The recombinant algal organism of claim 21 , wherein the SGI1 polypeptide has at least 90% sequence identity to SEQ ID NO: 14.
23. The recombinant alga of claim 20 , wherein the recombinant alga is an alga of the genus Oocystis.
24. A biomass product comprising the recombinant alga of claim 1 .
25. A method of producing a composition containing lipids by cultivating the recombinant algal organism of claim 1 and thereby producing a composition containing lipids.