School of Life Sciences, School of Energy Research, Xiamen University, Xiamen 361005, PR China.
Bioresour Technol. 2010 Dec;101(24):9605-11. doi: 10.1016/j.biortech.2010.07.095. Epub 2010 Jul 29.
Sequential dark-photo fermentations (SDPF) was used for hydrogen production from bagasse, an acetaldehyde dehydrogenase (adhE) gene inactivated Klebsiella oxytoca HP1 (DeltaadhE HP1) mutant was used to reduce the alcohol content in dark fermentation (DF) broths and to further enhance the hydrogen yield during the photo fermentation (PF) stage. Compared with that of the wild strain, the ethanol concentration in DF broths of DeltaadhE HP1 decreased 69.4%, which resulted in a hydrogen yield in the PF stage and the total hydrogen yield over the two steps increased by 54.7% and 23.5%, respectively. The culture conditions for hydrogen production from acid pretreated bagasse by SDPF were optimized as culture temperature 37.5 degrees C, initial pH 7.0, and cellulase loading 20 FPA/g in the DF stage, with initial pH 6.5, temperature 30 degrees C and photo intensity 5,000 lux in the PF stage. Under optimum conditions, by using DeltaadhE HP1 and wild type strain, the H(2) yields were 107.8+/-5.3 mL H(2)/g-bagasse, 96.2+/-4.4 mL H(2)/g-bagasse in DF and 54.3+/-2.2 mL H(2)/g-bagasse, 35.1+/-2.0 mL H(2)/g-bagasse in PF, respectively. The special hydrogen production rate (SHPR) were 5.51+/-0.34 mL H(2)/g-bagasseh, 4.95+/-0.22 mL H(2)/g-bagasseh in DF and 0.93+/-0.12 mL H(2)/g-bagasseh, 0.59+/-0.07 mL H(2)/g-bagasseh in PF, respectively. The total hydrogen yield from bagasse over two steps was 162.1+/-7.5 mL H(2)/g-bagasse by using DeltaadhE HP1, which was 50.4% higher than that from dark fermentation only. These results indicate that reducing ethanol content during dark fermentation by using an adhE inactivated strain can significantly enhance hydrogen production from bagasse in the SDPF system. This work also proved that SDPF was an effective way to improve hydrogen production from bagasse.
序贯暗发酵-光发酵（SDPF）被用于从甘蔗渣中生产氢气，使用一种醛脱氢酶（adhE）基因失活的产酸克雷伯氏菌（Klebsiella oxytoca）HP1（DeltaadhE HP1）突变体来降低暗发酵（DF）发酵液中的酒精含量，并进一步提高光发酵（PF）阶段的氢气产量。与野生菌株相比，DeltaadhE HP1 的 DF 发酵液中的乙醇浓度降低了 69.4%，这使得 PF 阶段的氢气产量和两步法的总氢气产量分别提高了 54.7%和 23.5%。通过 SDPF 从酸预处理甘蔗渣中生产氢气的培养条件优化为 DF 阶段培养温度 37.5℃，初始 pH 值 7.0，纤维素酶用量 20FPA/g，PF 阶段初始 pH 值 6.5，温度 30℃，光强 5000lux。在最佳条件下，使用 DeltaadhE HP1 和野生型菌株，DF 和 PF 阶段的 H2 产率分别为 107.8+/-5.3 mL H2/g-甘蔗渣和 96.2+/-4.4 mL H2/g-甘蔗渣，54.3+/-2.2 mL H2/g-甘蔗渣和 35.1+/-2.0 mL H2/g-甘蔗渣。特殊氢气产率（SHPR）分别为 5.51+/-0.34 mL H2/g-甘蔗渣 h、4.95+/-0.22 mL H2/g-甘蔗渣 h 在 DF 阶段和 0.93+/-0.12 mL H2/g-甘蔗渣 h、0.59+/-0.07 mL H2/g-甘蔗渣 h 在 PF 阶段。使用 DeltaadhE HP1，两步法从甘蔗渣中获得的总氢气产量为 162.1+/-7.5 mL H2/g-甘蔗渣，比仅进行暗发酵提高了 50.4%。这些结果表明，在暗发酵过程中使用 adhE 失活菌株降低乙醇含量可以显著提高 SDPF 系统从甘蔗渣中生产氢气的能力。这项工作还证明了 SDPF 是提高甘蔗渣产氢的有效方法。
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