Cold stress treatment enhances production of metabolites and biodiesel feedstock in Porphyridium cruentum via adjustment of cell membrane fluidity

Porphyridium cruentum, a cell-wall-free marine Rhodophyta microalga was cultured under a 5-day cold stress at 0 degrees C and 15 degrees C, after reaching the late logarithmic growth phase. Compared with the control at 25 degrees C, the cold stress treatment significantly (p < 0.05) increased the microalgal biomass (1.21-fold); the amounts of total polyunsaturated fatty acids (1.22-fold); individual fatty acids including linoleic acid (1.50-fold) and eicosatrienoic acid (1.85-fold), and a major carotenoid zeaxanthin (1.53-fold). Furthermore, production of biodiesel feedstock including total C16 + C18 fatty acids was significantly enhanced (p < 0.05) by 1.18-fold after the cold stress treatment. Principal component analysis further indicated that the biosynthetic pathways of fatty acids and carotenoids in this microalga were correlated with the cold stress treatment. These results suggested that P. cruentum had adjusted its cellular membrane fluidity via an 'arm-raising and screw-bolt fastening' mechanism mediated by the synergistic roles of cis-unsaturated fatty acids and carotenoids. The insight obtained from the responses to cold stress in P. cruentum could be a novel technological approach to enhance the production of microalgal metabolites and biodiesel feedstock. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study showed that Porphyridium cruentum exhibited increased production of fatty acids and carotenoids under cold stress, leading to enhanced production of biodiesel feedstock. Principal component analysis indicated that the biosynthetic pathways of fatty acids and carotenoids in this microalga were influenced by cold stress.