ASTAXANTHIN PRODUCTION USING A RECOMBINANT MICROBIAL HOST CELL

摘要

A recombinant microbial host cell is provided capable of producing astaxanthin from β-carotene without a measurable concomitant accumulation of ketolated or hydroxylated intermediates such as adonixanthin, zeaxanthin, adonirubin, echinenone, 3-hydroxyechinenone, 3′-hydroxyechinenone, canthaxanthin, and β-cryptoxanthin. Specifically, a β-carotene producing microbial host cell was engineered to express two heterologous genes, a β-carotene ketolase from Chlamydomonas reinhardtii in combination with a carotenoid hydroxylase from Brevundimonas vesicularis or Arabidopsis thaliana.

主权项

1. A recombinant microbial host cell comprising:
a. a set of β-carotene biosynthesis pathway genes; b. at least one expressible genetic construct encoding the β-carotene ketolase from Chlamydomonas reinhardtii; and c. at least one expressible genetic construct encoding a carotenoid hydroxylase selected from Brevundimonas sp., Arabidopsis thaliana or a combination thereof;
wherein the recombinant microbial host cell produces astaxanthin from β-carotene and does not concomitantly accumulate a significant amount of any one of the following ketolated and/or hydroxylated carotenoid intermediates: adonixanthin, zeaxanthin, adonirubin, echinenone, 3-hydroxyechinenone, 3′-hydroxyechinenone, canthaxanthin or β-cryptoxanthin; wherein the ratio of astaxanthin to any one of the ketolasted and/or hydroxylated carotenoid intermediates as measured by dry cell weight is at least 75:1, preferably at least 100:1, more preferably at least 125:1, and most preferably at least 150:1.