Rapidly Improving High Light and High Temperature Tolerances of Cyanobacterial Cell Factories Through the Convenient Introduction of an AtpA-C252F Mutation.

Shanshan Zhang,Xuexia Zeng,Yangkai Duan,Guodong Luan,Xuefeng Lu,Jiahui Sun,Sini Zheng

doi:10.3389/fmicb.2021.647164

Abstract

Photosynthetic biomanufacturing is a promising route for green production of biofuels and biochemicals utilizing carbon dioxide and solar energy. Cyanobacteria are important microbial platforms for constructing photosynthetic cell factories. Toward scaled outdoor cultivations in the future, high light and high temperature tolerances of cyanobacterial chassis strains and cell factories would be determinant properties to be optimized. We proposed a convenient strategy for rapidly improving high light and high temperature tolerances of an important cyanobacterial chassis Synechococcus elongatus PCC 7942 and the derived cell factories. Through introduction and isolation of an AtpA-C252F mutation, PCC 7942 mutants with improved high light and high temperature tolerances could be obtained in only 4 days with an antibiotics-free mode. Adopting this strategy, cellular robustness and sucrose synthesizing capacities of a PCC 7942 cell factory were successfully improved.

Highlights

With resource shortages and environmental pollution issues becoming increasingly prominent, photosynthetic biomanufacturing provides important options for the green and sustainable production of biofuels and biochemicals (Melis, 2009; Lu, 2010)
We proposed a convenient strategy for rapidly improving high light and high temperature tolerances of PCC 7942 derived cell factories by targeted mutagenesis of AtpA-C252
We have introduced an Escherichia coli sourced sucrose permease CscB into PCC 7942 to facilitate the secretory production of sucrose under salts stress and overexpressed the native sucrose-phosphate synthase Sps to enhance sucrose synthesis (Duan et al, 2016; Qiao et al, 2018)

Summary

INTRODUCTION

With resource shortages and environmental pollution issues becoming increasingly prominent, photosynthetic biomanufacturing provides important options for the green and sustainable production of biofuels and biochemicals (Melis, 2009; Lu, 2010). Overexpression of specific heat shock proteins improved high temperature tolerance of cyanobacterial cells (Chaurasia and Apte, 2009; Su et al, 2017), and reduction of light harvesting antenna led to improved tolerances to high light stress (Kirst et al, 2014). Implementations of these strategies rely on antibiotic resistance selection based on genetic manipulations and require long-term cultivations and passages for isolation of the homozygous mutant, and the entire cycle would usually take several weeks. Cellular robustness and sucrose synthesizing capacities of a previously constructed PCC 7942 cell factory were significantly optimized, increasing the sucrose productivities by nearly onefold

RESULTS AND DISCUSSION

MATERIALS AND METHODS

CONCLUSION

DATA AVAILABILITY STATEMENT