%A Di Li,Swati Yewalkar,Xiaotao Bi,Sheldon Duff,Dusko Posarac,Heli Wang,Layne A. Woodfin,Jan-Hendrik Hehemann,Sheila C. Potter,Francis E. Nano %T Heterologous expression of LamA gene encoded endo-β-1,3-glucanase and CO2 fixation by bioengineered Synechococcus sp. PCC 7002 %0 Journal Article %D 2017 %J Front. Environ. Sci. Eng. %J Frontiers of Environmental Science & Engineering %@ 2095-2201 %R 10.1007/s11783-017-0910-1 %P 9- %V 11 %N 2 %U {https://journal.hep.com.cn/fese/EN/10.1007/s11783-017-0910-1 %8 2017-04-25 %X

Maximum growth rate of Synechococcus mutant was 0.083 h1 with 5% CO2.

Maximum biomass concentration of Synechococcus mutant was 3.697 g·L1.

Synechococcus mutant can tolerate gas aeration with 15% CO2.

Maximum specific activity of laminarinase was 4.325 U·mg1 dry mass.

Optimal pH and temperature of laminarinase activity were 8.0 and 70°C.

The gene for the catalytic domain of thermostable endo-β-1,3-glucanase (laminarinase) LamA was cloned from Thermotoga maritima MSB8 and heterologously expressed in a bioengineered Synechococcus sp. PCC 7002. The mutant strain was cultured in a photobioreactor to assess biomass yield, recombinant laminarinase activity, and CO2 uptake. The maximum enzyme activity was observed at a pH of 8.0 and a temperature of 70°C. At a CO2 concentration of 5%, we obtained a maximum specific growth rate of 0.083 h1, a biomass productivity of 0.42 g·L1·d1, a biomass concentration of 3.697 g·L1, and a specific enzyme activity of the mutant strain of 4.325 U·mg1 dry mass. All parameters decreased as CO2 concentration increased from 5% to 10% and further to 15% CO2, except enzyme activity, which increased from 5% to 10% CO2. However, the mutant culture still grew at 15% CO2 concentration, as reflected by the biomass productivity (0.26 g·L1·d1), biomass concentration (2.416 g·L1), and specific enzyme activity (3.247 U·mg1 dry mass).