Hu Jiajun, Wang Lei, Zhang Shiping, Le Yiquan, Fu Xiaohua
School of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai, 200092, China.
Appl Biochem Biotechnol. 2014 Aug;173(8):2307-20. doi: 10.1007/s12010-014-1036-6. Epub 2014 Jul 1.
When compared with H2, mixed electron donors (MED), comprising S(2-), S2O3 (2-), and NO2 (-), could generally improve the CO2-fixing efficiency of nonphotosynthetic microbial communities (NPMCs). However, a large amount of abiotic precipitates combined with bacteria produced during culture may be unfavorable for the recycling and reuse of bacteria. The main component of the abiotic precipitates is S(0), which influences the enrichment and reuse of bacteria but is not conducive for CO2 fixation in the subsequent step. In this study, a two-step culture method (TSCM), employing H2 and MED, respectively, was verified to be feasible for improving the CO2-fixing efficiency of NPMCs in the second step. In the TSCM, the net-fixed CO2 increased to 854 mg/L and abiotic precipitates were not produced in the medium. Sequence analysis of 16 s rDNA from NPMC indicated the presence of microbial symbioses in the NPMC, supporting the possible applications of TSCM.
与氢气（H₂）相比，由硫离子（S²⁻）、硫代硫酸根离子（S₂O₃²⁻）和亚硝酸根离子（NO₂⁻）组成的混合电子供体（MED）通常可以提高非光合微生物群落（NPMC）的二氧化碳固定效率。然而，培养过程中产生的大量非生物沉淀物与细菌结合，可能不利于细菌的循环利用。非生物沉淀物的主要成分是单质硫（S⁰），它会影响细菌的富集和再利用，但不利于后续步骤中的二氧化碳固定。在本研究中，分别采用氢气和混合电子供体的两步培养法（TSCM）被证实可在第二步提高非光合微生物群落的二氧化碳固定效率。在两步培养法中，净固定二氧化碳增加到854毫克/升，且培养基中未产生非生物沉淀物。对非光合微生物群落16 s rDNA的序列分析表明该群落中存在微生物共生关系，这支持了两步培养法的潜在应用。
