A novel thermophilic β-carotene 15,15′-monooxygenase with broad substrate specificity from the marine bacterium Candidatus Pelagibacter sp. HTCC7211

Abstract

To characterize a novel thermophilic bcarotene 15,15 0 -monooxygenase BCMO 7211 isolated from the marine bacterium Candidatus Pelagibacter sp. HTCC7211. BCMO 7211 was functionally overexpressed in Escherichia coli and purified to homogeneity by Ni-NTA affinity chromatography and Superdex-200 gel filtration chromatography. Labeling experiments with H 2 18 O demonstrated that the oxygen atom in the terminal aldehyde group of the produced retinal molecules was provided from both molecular oxygen and water, indicating that BCMO 7211 is the first characterized bacterial b-carotene 15,15 0monooxygenase. BCMO 7211 exhibited broad carotenoid substrate specificity toward a-carotene, b-cryptoxanthin, b-carotene, zeaxanthin, and lutein. The optimum temperature, pH, and concentrations of the substrate and enzyme for retinal production were 60 °C, 9.0, 500 mg b-carotene/L, and 2.5 U/ml, respectively. Under optimum conditions, 888.3 mg/L retinal was produced in 60 min with a conversion rate of 89.0% (w/w). BCMO 7211 is a potential candidate for the enzymatic synthesis of retinal in biotechnological applications.

An extensive review of marine pigments: sources, biotechnological applications, and sustainability

“…HTCC7211 (Long et al. 2021 ). To reduce the interference of other compounds and the cost, adsorbents (zeolite, molecular sieve, ammonium Y zeolite, silver-exchanged zeolite, mesoporous carbon) and nanoparticles (zinc oxide, graphene oxide, gold, and silver) were proposed to purify R-phycoerythrin from marine macroalga Gelidium pusillum .…”

“…Ni-NTA affinity chromatography and Superdex-200 gel filtration chromatography have been used to purify the thermophilic β-carotene 15,15′-monooxygenase BCMO 7211 isolated from the marine bacterium Candidatus Pelagibacter sp. HTCC7211 (Long et al 2021). To reduce the interference of other compounds and the cost, adsorbents (zeolite, molecular sieve, ammonium Y zeolite, silver-exchanged zeolite, mesoporous carbon) and nanoparticles (zinc oxide, graphene oxide, gold, and silver) were proposed to purify R-phycoerythrin from marine macroalga Gelidium pusillum.…”