Expanding the upper‐temperature boundary for the microalga Picochlorum sp. (BPE23) by adaptive laboratory evolution. Issue 5 (5th February 2022)

• Record Type: Journal Article
• Authors: Barten, Robin; Peeters, Teun; Navalho, Sofia; Fontowicz, Louis; Wijffels, Rene H.; Barbosa, Maria
• Is Part Of: Biotechnology journal. Volume 17:Issue 5(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-05
• Subjects: adaptive laboratory evolution -- diel temperature -- microalgae -- photobioreactor -- temperature; Biotechnology -- Periodicals; 660.605
• DOI: 10.1002/biot.202100659
• Languages: English
• ISSNs: 1860-6768

Abstract

Abstract: Closed photobioreactors reach temperatures that reduce microalgal production or even cause culture collapses. Cooling can maintain the temperature within tolerable boundaries, but cooling is energy‐intensive and expensive. Thermotolerant microalgal strains can reduce dependence on such cooling. In this study, adaptive laboratory evolution was performed for 390 days to further increase the maximal tolerable temperature for the already thermotolerant microalgae Picochlorum sp. (BPE23) . The parental wild‐type strain of Picochlorum sp. (BPE23) exhibited a maximum mid‐day growth temperature of 47.5°C, whereas the isolated clones grew up to 49°C. At a lower temperature of 40°C, the growth rate and absorption cross‐sectional area were similar for the wild‐type strain and the evolved clones. Interestingly, the clones showed a 46% increase in cell volume compared to the wild‐type strain. The evolved clones with an expanded upper‐temperature boundary can be applied for broader temperature control of 1.5°C, without trade‐off effects at lower temperatures. Graphical Abstract and Lay Summary: Photobioreactors are currently cooled to prevent productivity losses in microalgal cultivation. In this study, performed adaptive laboratory evolution on Picochlorum sp. (BPE23) to increase the tolerance to mid‐day peak temperatures. The evolved strains can be used to reduce cooling costs without a trade‐off on productivity.