Abstract:[Objective] To breed new Spirulina strains with low-medium temperature adaptability for expanding the geographical scope and time, increasing the yield, and reducing the cost of Spirulina cultivation. [Methods] The single cells or spheroplasts of Spirulina platensis ZJU0116 in large-scale cultivation were prepared by tissue homogenization and centrifugation. They were treated with 0.6% ethyl methane sulfonate for 30 min and 2.4 kGy 60Co gamma ray, and then screened by low-temperature stress with 5 times of cold (12 ℃)/hot (38 ℃) abrupt alternation. The single filaments were cultured separately for the establishment of temperature adaptation surface, determination of protein content, and test of large-scale cultivation. [Results] We obtained a low-medium temperature adaptive mutant, which was named ZJU0116(LMTA), with the protein content equivalent to that of ZJU0116 and the temperature adaptation surface and average daily yield increased by 10.7% and 10.9%, respectively. ZJU0116(LMTA) had the helix number 54.4% lower, the filament length 42.1% lower, and the pitch 28.8% higher than its parent ZJU0116. Moreover, the randomly amplified polymorphic DNA (RAPD) analysis indicated that the amplification with the random primer S30 for ZJU0116(LMTA) produced an additional band at 470 bp, which revealed significant polymorphisms between ZJU0116(LMTA) and ZJU0116. [Conclusion] ZJU0116(LMTA) has good thermal adaptability and stable production, with a 10% increase in the dry algae powder output in large-scale cultivation. The new strain will promote the development of Spirulina industry towards a new stage of deep integration of the “dual carbon” goal and high-quality upgradation.
