Heterologous expression of
Di Li,Swati Yewalkar,Xiaotao Bi,Sheldon Duff,Dusko Posarac,Heli Wang,Layne A. Woodfin,Jan-Hendrik Hehemann,Sheila C. Potter,Francis E. Nano
《环境科学与工程前沿（英文）》
2017年
第11卷
第2期
doi:
10.1007/s11783-017-0910-1
摘要：
Maximum growth rate of mutant was 0.083 h with 5% CO . Maximum biomass concentration of mutant was 3.697 g·L . mutant can tolerate gas aeration with 15% CO . Maximum specific activity of laminarinase was 4.325 U·mg 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 h , a biomass productivity of 0.42 g·L ·d , a biomass concentration of 3.697 g·L , and a specific enzyme activity of the mutant strain of 4.325 U·mg 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·L ·d ), biomass concentration (2.416 g·L ), and specific enzyme activity (3.247 U·mg dry mass).
关键词：
Synechococcus sp. PCC 7002
Thermotoga maritima
LamA gene
Endo-β-1
3-glucanase
CO2 fixation
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