Carotenoid production from nondetoxified xylose mother liquid or corncob hydrolysate with engineered Kluyveromyces marxianus

Carotenoids are widely utilized in the food, pharmaceutical and nutraceutical industries. Here, Kluyveromyces marxianus was engineered to overproduce carotenoids from corncob hydrolysate or xylose mother liquid (XML, a byproduct of commercial xylose purification). First, the toxicity of fat-soluble carotenoids to cells was reduced by employing xylose inducible promoters using with a two-temperature strategy to separate cell growth and product accumulation. Then, through further engineering and optimization of the carotenoid biosynthesis pathway, 1506.7 mg/L lycopene, 988.5 mg/L 8-carotene or 142.9 mg/L astaxanthin were produced with glucose and xylose by K. marxianus. Finally, 397.7 mg/L and 279.7 mg/L lycopene, 297.3 mg/L and 108.8 mg/L 8-carotene, and 86.4 mg/L and 56.8 mg/L astaxanthin were produced with nonsterilized and nondetoxified XML or corncob hydrolysate after nitrogen source optimization. To our knowledge, the produced amounts of lycopene, 8-carotene and astaxanthin from lignocellulose biomass by yeast in this study were higher than those in previous reports.

Automated summary

The study engineered K. marxianus to efficiently produce carotenoids from xylose and glucose. By employing a two-temperature strategy and optimizing the carotenoid biosynthesis pathway, the researchers achieved higher yields of carotenoids compared to previous studies.