Chlorophyll deficient algal cell with improved growth and production

Abstract

Chlorophyll deficient algal strains, methods of making chlorophyll deficient algal strains, and methods of their use are provided.

1 . An isolated algal cell of the genus  Nannochloropsis , the algal cell having less chlorophyll content than a wild-type cell,
 wherein the algal cell comprises at least one polymorphism in comparison to a wild-type cell, and   wherein the at least one polymorphism is selected from the group consisting of the polymorphisms encoded by: SEQ ID NOS:1-51.   
     
     
         2 . The isolated algal cell of  claim 1 , wherein the at least one polymorphism is selected from the group consisting of SEQ ID NOS:1-11. 
     
     
         3 . The isolated algal cell of  claim 1 , wherein the algal cell has less than about 50% of the chlorophyll content of a wild-type cell. 
     
     
         4 . The isolated algal cell of  claim 1 , wherein the mRNA expression of 1, 2, 3, 4 or more mRNAs selected from the group consisting of mRNAs at least partially encoded by SEQ ID NOS:52-68 is less than about ½, 1/10 th , 1/50 th , 1/100 th , or 1/1000 th  of the expression of the mRNA in a wild-type cell. 
     
     
         5 . The isolated algal cell of  claim 4 , wherein the mRNA expression compared to a wild-type algal cell is mRNA expression of log-phase cultures in F2N2 media. 
     
     
         6 . The isolated algal cell of  claim 1 , wherein the algal cell exhibits a higher growth productivity as measured by grams of dry weight algal cells per square meter per day when grown in outdoor cultivation ponds as compared to a wild-type cell. 
     
     
         7 . The isolated algal cell of  claim 6 , wherein the algal cell exhibits at least a 10% higher growth productivity as measured by grams of dry weight algal cells per square meter per day when grown in outdoor cultivation ponds as compared to a wild-type cell. 
     
     
         8 . The isolated algal cell of  claim 1 , wherein the algal cell contains at least about 3.9-5% EPA per gram dry weight. 
     
     
         9 . The isolated algal cell of  claim 1 , wherein the concentration of EPA as a proportion of total fatty acids is at least 5-15%, or 15-30%, higher than the wild-type cell. 
     
     
         10 . The isolated algal cell of  claim 9 , wherein the concentration of EPA as a proportion of total fatty acids is at least about 30%. 
     
     
         11 . The isolated algal cell of  claim 1 , wherein the algal cell contains no, or substantially no, or less than about 0.5% Docosahexaenoic acid (DHA) per gram dry weight. 
     
     
         12 . The isolated algal cell of  claim 1 , wherein the algal cell contains less than about 0.61% ARA per gram dry weight. 
     
     
         13 . The isolated algal cell of  claim 1 , wherein the algal cell has an EPA/ARA mass ratio of greater than about 5:1. 
     
     
         14 . A composition comprising dry whole  Nannochloropsis  biomass, wherein the biomass comprises an algal cell of  claim 1 . 
     
     
         15 . A process for obtaining a total algal oil rich in EPA, the process comprising:
 cultivating any one of the algal cells of  claim 1 ; and   isolating the oil.   
     
     
         16 . A method of making any one of the algal cells of  claim 1 , the method comprising:
 modifying the genome of an algal cell from a parent algal cell line to introduce a polymorphism selected from the group consisting of the polymorphisms encoded by SEQ ID NOS:1-51; or   reducing the expression of an mRNA transcript in an algal cell, wherein the mRNA transcript is selected from the group consisting of the transcripts encoded by, or partially encoded by, SEQ ID NOS:52-68.