Production of the Marine Carotenoid Astaxanthin by Metabolically Engineered Corynebacterium glutamicum

Abstract

Astaxanthin, a red C40 carotenoid, is one of the most abundant marine carotenoids. It is currently used as a food and feed additive in a hundred-ton scale and is furthermore an attractive component for pharmaceutical and cosmetic applications with antioxidant activities. Corynebacterium glutamicum, which naturally synthesizes the yellow C50 carotenoid decaprenoxanthin, is an industrially relevant microorganism used in the million-ton amino acid production. In this work, engineering of a genome-reduced C. glutamicum with optimized precursor supply for astaxanthin production is described. This involved expression of heterologous genes encoding for lycopene cyclase CrtY, β-carotene ketolase CrtW, and hydroxylase CrtZ. For balanced expression of crtW and crtZ their translation initiation rates were varied in a systematic approach using different ribosome binding sites, spacing, and translational start codons. Furthermore, β-carotene ketolases and hydroxylases from different marine bacteria were tested with regard to efficient astaxanthin production in C. glutamicum. In shaking flasks, the C. glutamicum strains developed here overproduced astaxanthin with volumetric productivities up to 0.4 mg·L−1·h−1 which are competitive with current algae-based production. Since C. glutamicum can grow to high cell densities of up to 100 g cell dry weight (CDW)·L−1, the recombinant strains developed here are a starting point for astaxanthin production by C. glutamicum.

Turning a green alga red: engineering astaxanthin biosynthesis by intragenic pseudogene revival in Chlamydomonas reinhardtii

“…Given these limitations, genetic engineering approaches have been undertaken to enable astaxanthin production in different biotechnological host organisms in order to generate suitable alternatives to traditional H. lacustris production processes. Astaxanthin synthesis has indeed been demonstrated in many different organisms such as fermentative bacteria (Henke et al, 2016;Park et al, 2018) as well as photosynthetic cyanobacteria (Harker and Hirschberg, 1997), and eukaryotic hosts including yeasts (Kildegaard et al, 2017;Miura et al, 1998) and higher plants (Harada et al, 2014;Hasunuma et al, 2008;Huang et al, 2013;Jayaraj et al, 2008;Mann et al, 2000;Nogueira et al, 2017;Stalberg et al, 2003;Zhong et al, 2011) by the transgenic expression of keto-and hydroxylases. The results obtained were promising but with limited, industrial relevance due to the high costs of cultivation of these organisms and/or low productivity.…”

Turning a green alga red: engineering astaxanthin biosynthesis by intragenic pseudogene revival in Chlamydomonas reinhardtii

“…Given these limitations, genetic engineering approaches have been undertaken to enable astaxanthin production in different biotechnological host organisms in order to generate suitable alternatives to traditional H. lacustris production processes. Astaxanthin synthesis has indeed been demonstrated in many different organisms such as fermentative bacteria (Henke et al, 2016;Park et al, 2018) as well as photosynthetic cyanobacteria (Harker and Hirschberg, 1997), and eukaryotic hosts including yeasts (Kildegaard et al, 2017) , (Miura et al, 1998) and higher plants (Mann et al, 2000), (Stalberg et al, 2003) (Jayaraj et al, 2008). (Hasunuma et al, 2008), (Zhong et al, 2011) (Huang et al, 2013 (Harada et al, 2014) by the transgenic expression of keto-and hydroxylases.…”

Biosynthesis of Carotenoids and Apocarotenoids by Microorganisms and Their Industrial Potential

“…As summarized in Table 2, the engineered S. cerevisiae [69], Y. lipolytica [66], Kluyveromyces marxianus [70] and E. coli [71] have produced promisingly high titers and yields of astaxanthin. The recently achieved titers and yields [66,70,71] are from 10-fold to 100-fold higher than those previously reported in S. cerevisiae [72,73], E. coli [74,75], Corynebacterium glutamicum [76] and Xanthophyllomyces dendrorhous, previously as Phaffia rhodozyma [77][78][79].…”