Two-step process for ketocarotenoid production by a green alga, Chlorococcum sp. strain MA-1

Abstract

The production of ketocarotenoids (KCs) from Chlorococcum sp. strain MA-1 was investigated by a two-step process. In the first step, 18 g biomass l(-1) was achieved by feeding glucose to the heterotrophic cultures; in the second step, the high-density cultures were treated with light illumination or chemical stress in dark, respectively, to induce KC synthesis. Light-treated cultures could produce 103 mg total KCs l(-1) and 32 mg astaxanthin l(-1), three times higher than those from chemical-treated cultures, in the 10 days of induction. The percentages of individual KCs (hydroxyechinenone, canthaxanthin, adonirubin and astaxanthin) in the total KCs were not markedly influenced by the different stress conditions. The developed two-step process provides a feasible strategy for commercial production of ketocarotenoids by the green microalga, Chlorococcum sp. strain MA-1.

Genomic Foundation of Starch-to-Lipid Switch in Oleaginous Chlorella spp.

“…Such a controlled switch that exploits the advantages of both autotrophy and heterotrophy shows potential in largescale food and biofuel production. Similar switches have been found in many microalgae and have been exploited in cultivation (e.g., via high-light induction or change of nutritional mode) to improve the productivity of valuable cellular components such as astaxanthin, ketocarotenoid, and a-tocopherol (Ogbonna et al, 1999;Hata et al, 2001;Zhang and Lee, 2001). Nevertheless, the molecular mechanism underlying the switch remains unclear.…”

Optimized astaxanthin production in Chlorella zofingiensis under dark condition by response surface methodology

“…For all the cultures, cell growth rapidly increased during the first 6 d of cultivation but the cells in the fed-batch culture and the two-stage culture continued to grow rapidly until 14 d. It was demonstrated that the two-stage culture strategy was effective in improving astaxanthin production in Chlorococcum sp. and H. pluvialis (28,29). For astaxanthin production in H. pluvialis, the two-stage culture strategy was considered better than the one-stage system and suitable for mass production (30).…”

Enhancement of canthaxanthin production from Dietzia natronolimnaea HS-1 in a fed-batch process using trace elements and statistical methods

“…nov. (Duckworth et al, 1998), Brevibacterium KY-4313 (Nelis and De Leenheer, 1989), Bradyrhizobium strain ORS278 (Hannibal et al, 2000), and Gordonia jacobaea MV-1 (De Miguel et al, 2000); the halophilic archaeon Haloferax alexandrinus TM T (Asker and Ohta, 2002) and various green micro-algae, including Chlorella pyrenoidosa (Czygan, 1964), Chlorococcum sp. strain MA-1 (Zhang and Lee, 2001), and Chlorella zofingiensis (Li et al, 2006), there is clear potential for employing D. natronolimnaea HS-1 to synthesize canthaxanthin. Table 5 shows a comparative study between microbial sources of canthaxanthin.…”

“…A similar pattern has also been observed in some other carotenogenic strains such as Phaffia rhodozyma (Vazquez et al, 1997), Chlorococcum sp. (Zhang and Lee, 2001), Rhodotorula mucilaginosa (Aksu and Eren, 2005), Gordonia jacobaea (VeigaCrespo et al, 2005), and Sporobolomyces ruberrimus H110 .…”

“…KY-4313 (Nelis and De Leenheer, 1989)), green micro-algae (Chlorococcum sp. (Zhang and Lee, 2001), Chlorella zofingiensis (Li et al, 2006) and C. pyrenoidosa (Czygan, 1964)) and a halophilic archaeon Haloferax alexandrinus TM T (Asker and Ohta, 2002). Canthaxanthin pigment can be produced biotechnologically by different carotenogenic microbes, but they synthesize relatively low concentrations of canthaxanthin and so cannot compete economically with synthetic canthaxanthin (Nelis and De Leenheer, 1991).…”