College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 210009, People's Republic of China.
College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 210009, People's Republic of China.
Sci Rep. 2017 Aug 11;7(1):7940. doi: 10.1038/s41598-017-07207-7.
Clostridium tyrobutyricum ATCC25755 has been reported as being able to produce significant quantities of hydrogen. In this study, the exo-inulinase encoding gene cloned from Paenibacillus polymyxa SC-2 was into the expression plasmid pSY6 and expressed in the cells of C. tyrobutyricum. The engineered C. tyrobutyricum strain efficiently fermented the inulin-type carbohydrates from Jerusalem artichoke, without any pretreatment being necessary for the production of hydrogen. A comparatively high hydrogen yield (3.7 mol/mol inulin-type sugar) was achieved after 96 h in a batch process with simultaneous saccharification and fermentation (SSF), with an overall volumetric productivity rate of 620 ± 60 mL/h/L when the initial total sugar concentration of the inulin extract was increased to 100 g/L. Synthesis of inulinase in the batch SSF culture was closely associated with strain growth until the end of the exponential phase, reaching a maximum activity of 28.4 ± 0.26 U/mL. The overall results show that the highly productive and abundant biomass crop Jerusalem artichoke can be a good substrate for hydrogen production, and that the application of batch SSF for its conversion has the potential to become a cost-effective process in the near future.
凝结芽孢杆菌 ATCC25755 已被报道能够大量产生氢气。在这项研究中，从多粘类芽孢杆菌 SC-2 克隆的外切菊粉酶编码基因被插入表达质粒 pSY6 并在凝结芽孢杆菌细胞中表达。经过工程改造的凝结芽孢杆菌菌株能够有效地发酵菊苣型碳水化合物，而无需对生产氢气进行任何预处理。在分批同步糖化发酵（SSF）中，经过 96 小时后，在初始菊粉提取物总糖浓度增加到 100g/L 的情况下，实现了较高的氢气产率（3.7mol/mol 菊苣型糖），总体容积生产率为 620±60mL/h/L。在分批 SSF 培养物中，菊粉酶的合成与菌株生长密切相关，直到指数期结束，达到最大活性 28.4±0.26U/mL。总体结果表明，高产且丰富的生物质作物菊苣可以作为生产氢气的良好底物，而采用分批 SSF 对其转化具有在不久的将来成为一种具有成本效益的工艺的潜力。
